Review Article Progress and Challenges toward the

Review ArticleProgress and Challenges toward the Development of Vaccinesagainst Avian Infectious Bronchitis

Faruku Bande12 Siti Suri Arshad1 Mohd Hair Bejo13

Hassan Moeini4 and Abdul Rahman Omar13

1Department of Veterinary Pathology and Microbiology Faculty of Veterinary Medicine Universiti Putra Malaysia (UPM)43400 Serdang Selangor Malaysia2Department of Veterinary Services Ministry of Animal Health and Fisheries Development PMB 2109 Usman Faruk SecretariatSokoto 840221 Sokoto State Nigeria3Laboratory of Vaccine and Immunotherapeutics Institute of Bioscience Universiti Putra Malaysia (UPM) 43400 SerdangSelangor Malaysia4Department of Virus-Associated Tumours (F100) German Cancer Research Centre Im Neuenheimer Feld 24269120 Heidelberg Germany

Correspondence should be addressed to Siti Suri Arshad suriupmedumy

Received 27 December 2014 Revised 20 March 2015 Accepted 23 March 2015

Academic Editor Peirong Jiao

Copyright copy 2015 Faruku Bande et al This is an open access article distributed under the Creative Commons Attribution Licensewhich permits unrestricted use distribution and reproduction in any medium provided the original work is properly cited

Avian infectious bronchitis (IB) is a widely distributed poultry disease that has huge economic impact on poultry industry Thecontinuous emergence of new IBV genotypes and lack of cross protection among different IBV genotypes have been an importantchallenge Although live attenuated IB vaccines remarkably induce potent immune response the potential risk of reversion tovirulence neutralization by thematernal antibodies and recombination andmutation events are important concern on their usageOn the other hand inactivated vaccines induce a weaker immune response and may require multiple dosing andor the use ofadjuvants that probably have potential safety risks and increased economic burdens Consequently alternative IB vaccines arewidely sought Recent advances in recombinant DNA technology have resulted in experimental IB vaccines that show promisein antibody and T-cells responses comparable to live attenuated vaccines Recombinant DNA vaccines have also been enhancedto target multiple serotypes and their efficacy has been improved using delivery vectors nanoadjuvants and in ovo vaccinationapproaches Although most recombinant IB DNA vaccines are yet to be licensed it is expected that these types of vaccines mayhold sway as future vaccines for inducing a cross protection against multiple IBV serotypes

1 Background

Avian infectious bronchitis (IB) is an economically importantpoultry disease affecting the respiratory renal and reproduc-tive systems of chickens Although IB was first identified inNorthDakotaUSA [1] epidemiological evidences confirmedthe circulation of several IBV serotypes in different parts ofthe world Currently both classic and variant IBV serotypeshave been identified in most countries thus making IBcontrol and prevention a global challenge [2 3] The diseaseis associated with huge economic losses resulting fromdecreased egg production poor carcass weight and highmorbidity Mortality rate could be high in young chickens

especially with other secondary complications such as viraland bacterial infections [4]

Vaccinationhas been considered to be themost cost effect-ive approach to controlling IBV infection [5] However thisapproach has been challenged by several factors including theemergence of new IBV serotypes (currently over 50 variants)that show little or no cross protection [6] Importantlysome IBV strains to which vaccines become available mightdisappear as new variants emerged and thus necessitate thedevelopment of new vaccines [5] Until recently most IBVvaccines are based on live attenuated or killed vaccinesderived from classical or variant serotypes These vaccinesare developed from strains originating from the USA such

Hindawi Publishing CorporationJournal of Immunology ResearchVolume 2015 Article ID 424860 12 pageshttpdxdoiorg1011552015424860

2 Journal of Immunology Research

(a) (b)

Figure 1 Predicted 3-dimensional structure of S1-glycoprotein (a) and nucleocapsid protein (b) determinants of Massachusetts strain of avianinfectious bronchitis virus Structures are drawn using SWISS homology modeller available online at httpswissmodelexpasyorg

as M41 Ma5 Ark and Conn and Netherlands for exampleH52 and H120 as well as European strains such as 793BCR88 and D274 However studies have shown that vaccinesagainst these strains often lead to poor immune responseespecially against local strains Live attenuated IB vaccineshave also been shown to contribute to the emergence of newpathogenic IBV variants [7 8] Notably changes in geograph-ical distribution and tissue tropism have been observed inQX-like strains that initially emerged in China and spreadto cause great economic loss to poultry farmers in Asia[9] Russia [10] and Europe [11ndash14] This review is aimedat describing progress and challenges associated with IBVvaccine development Some aspects of viral-induced immuneresponses are discussed

2 Review

21 Aetiology and Genome Characteristics Avian infectiousbronchitis virus (IBV) together with Turkey coronavirus andBeluga whale coronavirus belongs to a Gammacoronavirussubgroup familyCoronaviridae orderNidovirales Althoughantigenically different members of Coronaviridae familysuch as SARS and MERS coronavirus share common struc-tural protein organisation Coronaviruses genome ismade upof a single stranded enveloped RNA that measures from 27 to32 kbmaking them the largest of theRNAviruses [15] Partic-ularly IBVgenomehas an average diameter of 80ndash120 nmanda typically large club of 20 nm with heavily glycosylated spikeprojections Four different genes encoding for the structuralproteins are found in IBV genome These are designated asspike (S) envelope (E) matrix (M) and nucleocapsid (N)The structural protein genes are also interspaced by genescoding for nonstructural and accessory proteins arranged inthe order of 51015840 to 31015840 directions as UTR-1a1ab-S3a-3b-E-M5a-5b-N-31015840-UTR-poly(A) [16] Of the structural protein genesthe S1 and N proteins contain epitopes responsible for hostimmune response (Figure 1)

22 Spike Glycoprotein The S-protein is heavily glycosylatedtransmembrane protein that spanned from 1160 amino

acids giving rise to 150ndash200 kDa It possessed a cleavedsignal sequence one transmembrane domain and a shortC-terminal tail [17] IBV S-protein is made up of 3400nucleotides posttranslationally cleaved into S1 (520 AASresidue) at the amino terminal and S2 (625 AAS residue)at the carboxyl terminal The two glycosylated proteins(S1 and S2) are anchored in the hydrophobic region nearthe carboxylic part of the S2 and cleaved by furin or itsrelated enzymes in the Golgi complex [18 19] Typically S1-glycoprotein plays a role in receptor binding while the S2contributes aids in the fusion of the virus [20] Of the twoS-glycoprotein genes the S1-gene is the important immuno-genic component and contained epitopes responsible forneutralizing antibody [21 22] It also determines receptorbinding as well as membrane fusion via virus-to-cell and cell-to-cell interactions [20]

23 The Nonstructural Genesrsquo 3a 3b 5a and 5b Proteins TheIBV genome possesses two small nsp genes 3 and 5 thatexpress three (3a 3b and 3c [E]) and two (5a and 5b) geneproducts respectively The 3a 3b 5a and 5b proteins of IBVshow a unique sequence characteristic when compared tomembers of group I and II coronaviruses [23] Although thespecific function of small protein remains unknown thesegenes are thought to contribute to virus virulence [23 24]Studies on the function of 5a-ns segment using reversegenetics have identified a possible link between ns-proteinand virus virulence however their contribution to virusreplication may be less relevant [25]

24 Matrix Protein The coronavirus matrix protein (M-protein) slightly protrudes to the surface and is situatedbetween 220 and 262 aa which is glycosylated on the N-terminal domain [26] Although members of group 2 coro-navirus are O-glycosylated IBV and members of group 1coronaviruses are glycosylatedwithN-linked oligosaccharidemolecules [27] The role of glycosylation of M-protein isstill not clear however using the MHV model it wasfound that cell infectedwithMHVcontainingN-glycosylated

Journal of Immunology Research 3

M-protein induces a better interferon response compared tothose infected with O-glycosylated M-protein while nongly-cosylated M-protein MHV infection resulted in a very poorinterferon response [28 29]

25 Nucleocapsid Protein During viral replication directinteraction occurs between N- and M-proteins [30] andsimilarly between N and nsp3a [31] Similarly an indirectinteraction has been suggested between N and S as a resultof S-M-protein segments interaction [30] Nucleocapsid pro-tein functionally binds with the genomic gRNA to forma helical ribonucleoprotein complex (RNPC) thus aidingtranscription replication translation and packaging of theviral genomeduring the replication process [32] CoronavirusN-protein also plays role in the induction of cytotoxic T-lymphocytes response due to the presence of CTL-inducingepitopes located at its carboxylic terminus [33 34] In addi-tion novel linear B-cells epitope peptides have been mappedwithin the nucleocapsid N-terminal domain [35]

26 Small Envelope Protein The IBV small envelope ldquoErdquo pro-tein is a scant protein and contains highly hydrophobic trans-membraneN-terminal and cytoplasmic C-terminal domainsThis protein has been suggested to be associated with viralenvelope formation assembly budding ion channel activityand apoptosis [36 37]

27 Serotypes and Strain Variations Currently there are sev-eral classical and variant IBV strains that have spread in dif-ferent countries [38]These strainsmay be closely or distantlyrelated as represented in the phylogenetic tree (Figure 2)Variation may arise due to a small change as little as 5 inthe S1 amino acid composition and may lead to alterationin cross protection among closely related serotypes Thusthe nature of IBV-S1 sequences is taken into consideration indesigning novel control strategies [39 40] Despite being firstidentified in USA the classical M41 serotype and the DutchH120 serotype are the most widely used vaccine viruses [3]However the World Organization for Animal Health (OIE)recommended that the distribution of IBV serotypes shouldinfluence the choice of vaccine for use in each geographicregion For example M41 Arkansas and Connecticut arecommon in USA while 491 (793B CR88) and D274are predominately found in Europe [41 42] Recently theChinese QX variants have emerged to cause outbreaks inEurope Asia the Middle East and Africa demonstratinga shift in geographical distribution and importance of theQX-like genotype This variation in strain distribution isindeed a challenge to IBV control programmes It is expectedthat other serotypes will continue to emerge as a result ofRNAmutation and recombination that lead to viral selectionpressure [3 43] Other local variants are common withinspecific regions andor countries but their global distributionis yet to be ascertained [44]

28RNAMutation andRecombination Mutation and recom-bination are important phenomena that shaped coronavirus

100

100

100

100

100

589

90

516

712709

567

507549

715922

68

917612

100

88

9555

995

985100 Florida

Conn32062ConnCvial2

M41-1979EgyptF03

AIBV-H52AIBV-H120

BeaudetteIBV-EP3M41NVAIBV

IBV-NGADMV564206

THA001V904

MH536595TX94aTX94b|

FRL-1450T05FRL-1450L05NLL-1449T04ITA902542005

L-1148K127703K101903IBVLaSP1708IBV06256109RF082010LaSP11609UKAV215007

QXIBVAIBV-LX4LH2

SDLY0612THA80151

711

006

M41|GQ219712

HNSG|GQ154654

Figure 2Neighbour-joining phylogenetics showing relationship in S1-glycoprotein of classical (pink) and variant (blue) IBV strains Thetree reliability was assessed using 1000-bootstrap confidence andbranching pattern is supported by 917ndash100 bootstraps values andassociated taxa show 82 pairwise identity Phylogenetic analysiswas carried out using Geneious software version R8

viral genomes [45] As with most RNA viruses mutationand recombination are two important events that alteror shape coronavirus viral genome Consequently a viralsubpopulation may evolve as a result of these importantgenetic events [16 43 46] Although it is difficult to ascertainhow IBV genome evolved three major theories have beenhypothesised as follows (i) the lack of RNA polymeraseproofreading activity could lead to errors in RNA genomewhich in turn result inmutation especially in the S1 spike gene(nucleotide insertions deletions or pointmutations) (ii)Theuse of vaccines especially the live attenuated vaccines type orpresence of multiple infections with different IBV serotypescontributes to recombination process that favours the emer-gence of new IBV variants [47] Mixture between variousgenetic mutants of the same coronavirus strains has beenshown to generate quasispecies viruses [48 49]Mutations inthe hypervariable S1 domain may affect viral subpopulationand result in new viruses with different pathogenicity as wellas virulence [43 46] It was found that regions encoding forthe nonstructural proteins 2 3 and 16 as well as the spikeglycoprotein exhibited the highest degree of recombination[50] Likewise experimental passaging of IBV in the presenceof other immunosuppressive viruses such as Marekrsquos diseasevirus chicken anaemia virus and infectious bursal diseasehas been suggested to affect IBV evolutionary dynamics [51]


3 Host Immune Response againstInfectious Bronchitis Virus

31Passive Immunity Maternally derived antibodies (MDAs)are important components of early protection against infec-tious agents It was shown thatMDAs last from days to weeksdepending on the virus strain Approximately 97 of birdswith MDAs are likely to be protected against IBV infectionat day one of age However this protection may decline tolt30 by age of 7 days thus demonstrating a limited durationof protection [52] Adoptive transfer of antibody also has beenreported to induce 120572120573 associated CD8+ T-lymphocytes thatprotected chickens from infection with virulent IBV strainthus signifying the role of passive immunity in IBV infection[52]

32 Innate Immune Responses The innate immune responseis important as the bodyrsquos first line of defence This responserelies on pathogen-associated molecular patterns (PAMPs)through specific pattern-recognition receptors (PRRs) thatare displayed on immune cells such as dendritic cells macro-phages lymphocytes and several nonimmune cells such asendothelial cells mucosal cells and fibroblasts Importantlythe type I interferon response which is characterized by thesecretions of chicken interferon alpha and interferon betaprovides efficient and rapid response against viral replicationthrough the activation of macrophages and natural killercells which further lead to the induction of adaptive immuneresponse The type II interferon response which is char-acterized by interferon gamma secretion is predominantlyproduced by the activatedNK cells dendritic cells andCD4+CD8+ T-lymphocytes This will further enhance leukocytesadhesion cause NK cells activation and increase antigenpresentation on the surface of APCs (macrophages anddendritic cells) and subsequently causes the expression ofMHC-I molecules and the development of adaptive response[53]

Specifically the toll-like receptors (TLRs) such as theTLR4 TLR5 TLR15 and TLR16 are involved in the innatesensing during viral infections [54] As with SARS virusand mouse hepatitis virus (MHV) significant upregulationof TLR4 has been observed in IBV infection suggesting itsrole in coronavirus infection irrespective of the host speciesinvolved [55] In IBV infection innate immune response hasbeen associated with the secretion of type I interferon in thetrachea lungs and kidney shortly after contact with the virus[56]This response however depends on the virulence of IBVas well as the host adaptability of the viral strain [57] Chickentype I interferons play important roles in the inhibition ofviral replication probably through interaction with TLRsmolecules and pattern-recognition receptors (PPRs) that arecrucial in detecting viral entry into the cells and for bridginginnate and adaptive immune responses [58ndash60] This issupported by the alteration in TLRs expression especiallyTLR2 TLR3 and TLR7 observed in the trachea lungs andkidney following IBV infection [60 61]

Administration of synthetic oligodeoxynucleotides (CpGODNs) led to a significant increase in the expression of

interferon gamma (IFN-gamma) interleukin 1-beta IL-6IL-8 and oligoadenylate synthetase [62] Similarly tran-scriptional analysis and cytokine profiling revealed that IL-1120573 MIP-1120573 and IFN signalling pathways may serve as abridge between innate and adaptive immunities followingIBV vaccination [63] The mechanism through which IBVinduces antiviral responses is very complex However it wassuggested that involvement of the JAK-STAT pathway andupregulation of genes related to immune response such asSTAT1 MYD88 IRF1 and NFKB2 are crucial to the hostimmune response whereas upregulation of genes related toviral protein synthesis such as elF1 helps the virus to evadeimmune defences [60 64]

33 Humoral Response Humoral immune response is asso-ciated with the inhibition of viral replication and has beenshown to correlate with IBV-specific antibody titre Antibodyresponse following IBV vaccination has been demonstratedin serum tracheal swabs and lacrimal secretion [6] Studieshave shown that both systemic (IgM and IgG) and mucosal(IgA) antibodies are essential determinants for effectiveclearance of the circulating virus [65] In addition IgA beingthe major immunoglobulin molecule for mucosal responseplays a role in antibody homing at tracheal or other mucosalpoints of viral entry [66] Remarkably IgM appeared 5 daysafter infection (dpi) peaked at days 8ndash10 and disappearedaround 18 days after infection while local responses correlatewith increased IgG levels and subsequent clearance of thevirus [56]

34 Cell-Mediated Immune Response The N-gene specificprotein response is associatedwith the induction of CTLs thatare responsible for clearance of IBV-infected cells [34 67]The CTLs response peaked after 10 days correlating witha decrease in clinical signs and viral clearance from lungs[68] A significant increase in the CD4+ and CD8+ T-cellshas been reported following vaccination with S1-gene specificIBV vaccines thus S1-gene importantly plays role in cell-mediated immune response [69] Viral clearance may beassociated with an increase in the expression of granzymesA during primary IBV infection and subsequent activation ofNK cells that aid in direct or targeted killing of IBV-infectedcells [70]

35 Mucosal Immune Response Despite advances in theunderstanding of mucosal immunology much is yet to belearned about mucosal immune responses in birds IBVreplication at Harderian glands (HG) conjunctiva influencesthe development of the mucosal immune response whichis characterized by the secretionsproduction of the specificIgAThis response has been further linked with the lymphoidexpansion at the head associated lymphoid tissues (HALTs)and subsequent induction of CTL response [71] Ocular vac-cination of chickenswith a recombinant nucleocapsid protein(rN) and recombinant S1-protein- (rS-) based IBV vaccine(via eye drop) induced significant cell-mediated immuneresponses without booster vaccination or adjuvants Birdsvaccinated with such vaccines were shown to be protected


against infection with virulent virus strain though the levelof IgA in the mucosa was higher in positive control birdsreceiving only H120 live attenuated vaccine [72]

4 Vaccines against Infectious Bronchitis Virus

41 Live Attenuated Vaccines Live attenuated IB vaccines arethe first generation IBV vaccines used to control IBV infec-tion in the field These vaccines are commercially availablefor application via drinking water or by coarse spray at 1day or within the first week of age Since the duration ofimmunity following live attenuated vaccines is short boostervaccination is carried out with the same or combinations ofother strains 2-3 weeks after prime vaccination [73] Mostof the commercially available live attenuated vaccines arederived from virulent strains such as Massachusetts-basedM41 serotype and the Dutch H52 and H120 strains althoughsome strains with regional or local impact have been used indifferent parts of the world [74ndash76]

Live vaccines often are used in broilers and as boostersfor breeders However variation may exist among coun-tries on the type of IBV vaccine strain approved for useThis should be guided by epidemiological knowledge ofthe locally or regionally prevalent strains For example inUSA the M41 H120 Arkansas Delaware Florida and JMK-derived vaccines are used frequently In Australia the B andC strains are used in UKEurope vaccine strains includeM41 491 and CR88 In Netherlands vaccination usingD274 and D1466 is commonly practiced [74] For logisticsand economic reasons some commercially available liveattenuated IBV vaccines have been combined with othervirus vaccines such as those against Newcastle disease virusMarekrsquos disease virus and infectious bursal disease virus(IBDV) However it is not clear whether the combinationmay influence immune response to the combined antigen[77] Few examples of commercially available live attenuatedvaccines include Nobilis IB-Ma5 (MSD Animal Health UK)fromMass serotype AviPro IBH120 which is also consideredas Mass serotype based vaccine from Dutch H120 strain(Lohmann Animal Health Germany) Nobilis 4-91 (MSDAnimal Health UK) Gallivac CR88 (Merial USA) fromEuropean strains Live attenuated vaccine POULVAC IBQXhas also been produced against the recently endemic QX-likeIBV strains (Pfizer France)

Some of the limitations of live attenuated viral vaccinesinclude reversion to virulence tissue damage and interfer-ence by MDA Tissue damage due to live vaccines may leadto pathological disorders or secondary bacterial infectionsespecially in day-old chick [78] Evidence has shown thatdespite efforts to reduce viral virulence by using 52 or 120passages to produceH52 andH120 IBV vaccines respectivelythese vaccines potentially cause considerable pathology ofthe trachea and may lead to a severe outbreak in the field[79 80] Another limitation of live attenuated IBV vaccines ispotential recombination between vaccine strains and virulentfield strains leading to the emergence of new IBV serotypes[7 75 81] In one study vaccination with live attenuatedH120vaccines was shown to encourage viral spread among broiler

chickens thus potentially supporting virus transmission andpersistence [82] To reduce problems associated with vaccinereversion researchers explore the options of using reversegenetic technology to create vaccine virus that is potentiallyapathogenic in the host but capable of replication andinducing immune response This has been shown in the caseof Beaudette virus carrying the S1-gene of virulent M41 IBVstrains [83 84]

42 Inactivated or Killed Vaccines Inactivated or killed vac-cines have been used either alone or in combination withlive attenuated IBV vaccines [85] These vaccines usually areadministered by injection to layers and breeders at 13 to 18weeks of age Since inactivated vaccines do not replicate theyare unlikely to revert and cause pathological effects Howevercompared to live attenuated vaccines killed vaccines aloneinduce shorter immune response characterized by antibodyproduction but not T-cell-mediated responses [34 86]Therefore inactivated vaccines in most cases require primingwith live attenuated vaccines large doses of adjuvants andormultiple vaccinations This may increase the costs associatedwith vaccine development and marketing thus limiting theirapplications [5] Being injectable administration of killedvaccines is either difficult or impracticable in large poultrysetting Likewise issues of injection-site reactions may alsolead to carcass rejection or reduction in value [87]

43 Recombinant Vaccines

431 Viral Vector-Based Vaccines The use of viral vectorsto deliver gene(s) of interest has been studied extensivelyRemarkably the ability of adenovirus vector to persist incells without causing pathology as well as their tropismto various dividing and nondividing cells allows sustainedantigen release It is also possible to package and expressdifferent immunogenic protein subunits in vector-based vac-cines without the necessary use of a whole virulent organism[88] Experimental recombinant vector vaccines have beendeveloped against IBV These vaccines were shown to inducesignificant increase in the immune response and protectagainst IB disease [69]

Although advances in viral vector vaccines seem promis-ing in providing effective immune response and for reducingthe problems associated with RNA mutation as seen in liveattenuated IBV vaccines [89] this technology does havelimitations that include issue of preexisting immunity ormaternally derived immunity that interferes with the live vec-tor itself and reduces the uptake of the antigen by the antigenpresenting cells and consequently the transgene expression aswell as specific immune response [90] Lack of proper proteinfolding and glycosylation in the host system and posttransla-tional modifications may alter the conformation and epitopearrangement that affect the immunogenicity and efficacy ofthe vaccineThese factors are currently given special attentionin design and selection of recombinant IBV vaccines [91]Recent study using a recombinant adenovirus vaccine con-taining IBV-S1-glycoprotein reported a significant antibodyresponse that conferred 90ndash100 protection against tracheal


lesions following homologous and heterologous challengewith Vic S (serotype B) or N162- (serotype C-) IBV strains[69]

Different protein antigens have been coexpressed withgenes encoding for genetic adjuvants for an enhancedimmune response In this regard Shi et al [92] showthat a fowl pox virus vaccine expressing IBV-S1-gene andchicken interferon-120574 gene [rFPV-IFN120574S1] enhances humoraland cell-mediated immune responses that protect chickensagainst homologous and heterologous challenge with LX4LHLJ04XI and LHB IBV strains Expression of IBV-S1-genewith chicken IL-18 in a recombinant fowl pox virus vectorproduced a significant increase in antibody titre CD4+ andCD8+ responses Similarly expression of IL-18 with IBV-S1-gene using a fowl pox virus vector (rFPV-S1IL18) resultedin 100 (2020) protection compared with only 75 (1520)protection rates in chickens receiving a construct containingS1 alone [93]

Oral immunization of mice with adenovirus vector wasshown to circumvent neutralization of the vector by pre-existing or maternally derived antibody [94] Interestinglyadenovirus vector vaccines have been shown to be promisingfor use in poultry oral vaccines Oral immunization thereforehas several advantages in poultrymedicine such as the ease ofapplication and reduction in stress associated with injectionhandling Although vector-based oral vaccine may lead toan adequate transgene specific antibody response improve-ments are needed for optimal T-cell response Modificationsof vector-based vaccines such as dose escalation nanoparticlecoating use of dual vectors (eg combination of pox andadenovirus-based vectors) andor swapping of adenovirushexon gene have been attempted to circumvent the effect ofpreexisting immunity but with some degree of success andreported toxicity in other infection models [88]

Lentivirus vectors are finding ways into veterinary vac-cines although lentivirus-based IB vaccines are uncommon[95] Overall only simultaneous comparative studies willassist in understanding the advantages of one vector overothers

432 Subunit and Peptide-Based Vaccines This technologyrequires the use of a segment or parts of the viral proteinto induce specific immune response While subunit vaccinesare derived frompathogen protein or polysaccharide peptidevaccines are made from pathogen peptides or a portion ofthe genome coding for immunogenic epitope [95] Epitopewithin S1- and N-gene has been targeted for the induction ofneutralizing antibodies as well as CTL responses respectively[22] For example a study has demonstrated that syntheticepitope peptide corresponding to S20-S255 reacted wellwith polyclonal antibodies against various IBV strains thusdemonstrating its potential applications for broad-based IBvaccines [96] These broad vaccines have also been mappedbetween 19 and 69 as well as 250 AAS sequences within thereceptor binding domainwhoseN-terminal plays role in viralentry [97]

Although at experimental stages of development syn-thetic and peptide vaccines have been shown to be promising

in the control of IBV some researchers have focused ondevelopingmultiepitope peptide vaccines for use againstwiderange of IBV serotypes Recently Yang et al [98] have devel-oped an IBV vaccine based on the multiple epitopes fromS1- and N-protein genes Expression analyses and immu-nization study using the designed synthetic peptides yieldedsignificant humoral and cell-mediated immune responsesthat resulted in gt80 protection after challenge with virulentvirus In another development a Lactococcus lactis bacterialsystem was used to deliver peptide vaccines orally and thisapproach was also reported to induce mucosal immuneresponse [99 100]

433 Plasmid DNA Vaccines Unlike recombinant vector-based vaccines involving a live vector DNA vaccines use aplasmid containing the gene(s) that code for an immunogenicprotein(s) of interest [101] Until recently no licensed poultryDNA vaccine is commercially available however this tech-nology has gained considerable attention and several prod-ucts are at various developmental or experimental trial stages[102] A DNA vaccine designated pDKArkS1-DP has beendeveloped based on the S1-genes of Arkansas IBV serotypesVaccination via in ovo route followed by immunization witha live attenuated vaccine at 2-week intervals resulted in asignificant immune response and 100 protection againstclinical disease On the other hand birds receiving either inovo DNA vaccination alone or live attenuated vaccine alonehad le80 protection after challenge with a virulent IBVstrain [103]

Apart from in ovo DNA vaccinations other novelapproaches have been evaluated For example intramuscularinjection of a liposome-encapsulated multiepitope DNA vac-cine designed from S1 S2 andN regions resulted in increasednumbers of CD4+ CD3+ and CD8+ CD3+ cells and aprotective immune response in 80 of the immunized birdsSome of the advantages of epitope-based vaccines include theability to package several immunogens in a small deliverysystem for targeted antibody and CTL responses [104]

Enhancement of a vaccine-induced immune responsewas achieved by coadministration of aDNAvaccine encodingfor IBV nucleocapsid or S1-glycoprotein genes with IL-2[105] or chicken granulocyte-macrophage stimulating factors(GM-CSF) respectively [106] In both cases significantincrease in the humoral and cell-mediated immune responseshas been reported However S1-encoded DNA vaccinesresulted in a better immune response and accorded 95protection that was slightly higher compared to the N-gene-encoded plasmid In another study a multivalent IBV-DNA vaccine encoding for the S1- N- and M-proteins wasdeveloped [98 107] The efficacy and protective capacity ofeach gene specific IBV-DNA vaccine were shown to improvewhen a cationic liposome carrier was used A similar resultwas obtained through boosting with an inactivated vaccine[107]

DNA vaccines have some limitations including route ofadministration since most DNA vaccines are administeredby injection thus making their application difficult in largecommercial poultry [108] However challenges related to


IB vaccines

Killed

Poor immune response

antibody mediated)

Injection-sitereactions

chemical adjuvants

Required

frequent

vaccinations

Time-consuming

and costly tobe produced

Potential reversion to

virulence

Mutation and recombination

effectsmaternal antibodies

DNA

Required technological

advances

Some of these types of

require

for effective delivery

Post-translational modification

alter some protein

due tomultiple

booster

byvaccines

may(only

RecombinantLive attenuated

Neutralization

carrier

Figure 3 Summary of major IB vaccines and important limitations associated with the vaccine types

the route of DNA vaccines administration could be overcomeusing in ovo DNA vaccination at the hatchery [103] or bygiving vaccines in drinking water or as a spray vaccine Ananoparticle-mediated DNA delivery will assist in protectingthe vaccine against enzymatic degradation and enhancestheir availability at mucosal surfaces for mucosal response[71] Since DNA vaccines could be used in the presenceof maternal antibodies their usage in poultry could beused to overcome challenges associated with vaccination ofyoung chicks against IBV infection Other advantages ofDNA vaccines include the induction of both antibody andT-cells immune response safety ability to express multipleproteins thermostability and cost of productionThey couldbe produced within a short period thus enabling handlingof the emerging virus threat Moreover modifications withcytokines adjuvant favour their choice in the control ofinfectious diseases of poultry [109]

44 Reverse Genetic Vaccines A reverse genetic vaccineinvolved a new technology of manipulating one or more viralgenes Recently this technology has been employed tomodifyIBV vaccine candidates [24 110 111] For example a recom-binant BeauR-IBV vaccine has been constructed recently bysubstituting the antigenic S1-glycoprotein of an apathogenicBeau-IBV strain with another S1-gene from pathogenic M41and European 491 strains respectively [112 113] Thesechanges resulted in protective immune responses withoutmaking the new BeauR strain pathogenic [113 114] SimilarlyZhou et al [84] have constructed a modified H120 (R-H120)virus that was found to retain some of its biological activitieswhen rescued after 5 passages in embryonated chicken eggsInterestingly a vaccine using this strain has been reportedto elicit a high level of haemagglutination inhibition (HI)antibody titre and a comparable protection rate comparedwith an intact H120-vaccinated group The future of reversegenetic vaccines may be born out of their potentials toabrogate issues of reversion to virulence as reported withlive attenuated vaccines Development of reverse genetic IBVvaccines that may overcome neutralization in the presenceof preexisting immunity although very difficult will surely

revolutionise the use of reverse genetic-based live attenuatedIBV vaccines But whether these newer generation vaccineswill increase or reduce the chances of mutation and viralselection pressure requires further studies A summary ofimportant limitations associatedwith IB vaccines is presentedin Figure 3

5 Expression and Delivery Systems

51 Vaccine Expression System In recombinant or subunitvaccines consideration is given to the presence or absenceof posttranslational modification associated with the vaccineantigen However thorough knowledge of the chemistry andbiology of the immunodominant antigen is needed to guideselection of a suitable expression system since outcomesmay differ frombacteria yeast mammalian baculovirus andplant expression systems [91] Different expression systemshave been used to generate recombinant protein antigenAn attempt using a vaccinia virus-based IBV vaccine failedto produce antigen enough to induce significant antibodyresponses in mice [115] It was proposed that the use of vac-cinia virus-based vaccinesmay be hindered by issues of safetyregarding vaccinia virus itself as well as its poor replicationability in avian cells [116] In another study a baculovirus-based vector was used to express the S1-glycoprotein ofKorean nephropathogenic KM91 strain Immunization ofchickens with the KM91 vaccine resulted in 50 kidneyprotection following a homologous challenge [89] Similarlyan S1-glycoprotein of IBV has been expressed in a transgenicpotato under the control of a cauliflower mosaic virus (35S)promoter gene This success could be useful in designingfood-based oral IB vaccines for use in poultry [117]

An improved ldquoBacMamrdquo virus surface display technologya modified strategy from baculovirus vectoring was usedrecently to display the S1-glycoprotein of IBV-M41 serotypeSubsequent experimental trials with the vaccine resulted insignificant humoral and cell-mediated immune responsesAbout 83 of the challenged birds were shown to be pro-tected which is comparable to 89 protection obtained inbirds immunized with commercial inactivated vaccine [118]


52 Delivery System The route of administration and deliv-ery method used in vaccination may affect vaccine-inducedimmune responses antigen presentation and type of MHCmolecule involved in the resultant response Live attenuatedIB vaccines have gained wide application via injection orallyand through aeronasal spray Killed or inactivated DNAvaccines and peptide-based vaccines are commonly usedvia injection routes Some improved methods have beenused to deliver recombinant proteins plasmid DNA andpeptide vaccine For example an IBV-DNA vaccine carry-ing S1- andor N-protein of IBV has been delivered orallyusing attenuated Salmonella enterica serovar Typhimuriumstrain Interestingly both humoral and mucosal immuneresponses were shown to significantly increase following oraland intranasal immunization Vaccinated chickens were pro-tected against homologous challenge [119] Other approachesrecorded success using a Lactococcus lactis bacterial systemto deliver IBV vaccine and this approach led to an efficientmucosal immune response [99 100]

Virus-like particle (VLP) has been a new focus of inter-est in vaccine development This technology utilizes theimmunogenic properties of a live virus without potential toretain pathogenic effects [120] A VLP-based IBV vaccine hasbeen developed using the IBV-M- and IBV-S-genes Immu-nization of mice with the candidate vaccines demonstratedhigh levels of cell-mediated immunity comparable with theresults obtained using H120 live attenuated virus vaccineSimilarly a chimeric VLP vaccine has been synthesized usingM1 protein of avian influenza H5N1 virus and fusion proteinldquoNAS1rdquo derived from IBV-S1 protein and the cytoplasmicand transmembrane domains of H5N1 avian influenza NAprotein The chimeric vaccine induced significant S1-specificantibodies in mice and chickens neutralizing antibody inchickens and increased IL-4 secretion in immunized mice[121] Putting together these findings there is a huge potentialfor VLP-based vaccines as innovative candidate and their usemay provide a delivery system for the newer IBV vaccine[120]

6 Conclusion

Despite spending huge amounts of money to control IBoutbreaks involving classical and newly emerging virusserotypes are constantly reported The increasing emergenceof IBV genotypes and lack of cross protective immunityhave augmented the pace of interest in the development ofnovel IBV vaccines Though live attenuated vaccines are stillcommon in the field theirmodification for example throughreverse genetic technology will be useful for reducing theeffects of reversion to virulence Viral vector vaccines havethe potential to facilitate efficient protein antigen productionand evoke effective immune response However as with liveattenuated vaccines effects of neutralization by maternalantibodies are of major concern regarding the use of vector-based vaccines since vaccination of parent poultry breeders ispracticed routinely There is no doubt that newer generationvaccines such as the recombinant vector DNA vaccinesplasmid DNA vaccines andmultiepitope vaccines may stand

as future alternatives as these vaccines have potential todeliver numerous antigens thus producing broad-based anti-body and cell-mediated immune response against numerousserotypes Importantly use of plasmidDNAvaccines circum-vents the effect of neutralization by preexisting immunity andtheir mode of action could be enhanced by delivery throughdifferent routes such as the mucosal and in ovo routes as wellas the use of novel delivery methods such as nanoparticlesand VLPs In any case future IBV vaccines must inducebroad protection against different IBV serotypes overcomematernal immunity meet international safety regulationsand be easier to apply and cost effective for wider acceptanceby poultry industry

List of Abbreviations

CTL Cytotoxic T lymphocytesMIP-1120573 Macrophage inflammatory protein 1120573JAKSTAT Janus kinasesignal transducers and

activators of transcriptionMYD88 Myeloid differentiation primary response

gene 88IRF1 Interferon regulatory factor 1NF120581B2 Nuclear factor NF-kappa-B p100

Conflict of Interests

Mention of trade names or commercial products in this paperis solely for the purpose of providing specific information anddoes not imply recommendation or endorsement by authorsor their affiliated institute The authors have no conflict ofinterests

Acknowledgments

The authors would like to thank the Ministry of ScienceTechnology and Innovation (MOSTI) and Ministry of Edu-cation (MOE) Malaysia for funding supports They thankDennis Lawler for editing this paper

References

[1] A Schalk andMHawn ldquoAn apparently new respiratory diseaseof baby chicksrdquo Journal of the American Veterinary MedicalAssociation vol 78 no 413ndash422 p 19 1931

[2] D Cavanagh ldquoCoronavirus avian infectious bronchitis virusrdquoVeterinary Research vol 38 no 2 pp 281ndash297 2007

[3] J J S de Wit J K A Cook and H M J F van der HeijdenldquoInfectious bronchitis virus variants a review of the historycurrent situation and control measuresrdquo Avian Pathology vol40 no 3 pp 223ndash235 2011

[4] M G R Matthijs J H H Van Eck W J M Landman and J AStegeman ldquoAbility of Massachusetts-type infectious bronchitisvirus to increase colibacillosis susceptibility in commercialbroilers a comparison between vaccine and virulent field virusrdquoAvian Pathology vol 32 no 5 pp 473ndash481 2003

[5] E N T Meeusen J Walker A Peters P-P Pastoret andG Jungersen ldquoCurrent status of veterinary vaccinesrdquo ClinicalMicrobiology Reviews vol 20 no 3 pp 489ndash510 2007


[6] J J De Wit ldquoDetection of infectious bronchitis virusrdquo AvianPathology vol 29 no 2 pp 71ndash93 2000

[7] E T McKinley D A Hilt and M W Jackwood ldquoAvian coro-navirus infectious bronchitis attenuated live vaccines undergoselection of subpopulations and mutations following vaccina-tionrdquo Vaccine vol 26 no 10 pp 1274ndash1284 2008

[8] E T McKinley M W Jackwood D A Hilt et al ldquoAttenuatedlive vaccine usage affects accurate measures of virus diversityand mutation rates in avian coronavirus infectious bronchitisvirusrdquo Virus Research vol 158 no 1-2 pp 225ndash234 2011

[9] Z H Mahmood R R Sleman and A U Uthman ldquoIsolationand molecular characterization of Sul0109 avian infectiousbronchitis virus indicates the emergence of a new genotype inthe Middle Eastrdquo Veterinary Microbiology vol 150 no 1-2 pp21ndash27 2011

[10] Y A Bochkov G V Batchenko L O Shcherbakova A VBorisov and V V Drygin ldquoMolecular epizootiology of avianinfectious bronchitis in Russiardquo Avian Pathology vol 35 no 5pp 379ndash393 2006

[11] M S Beato C de Battisti C Terregino A Drago I Capuaand G Ortali ldquoEvidence of circulation of a Chinese strain ofinfectious bronchitis virus (QXIBV) in ItalyrdquoVeterinary Recordvol 156 no 22 p 720 2005

[12] K J Worthington R J W Currie and R C Jones ldquoA reversetranscriptase-polymerase chain reaction survey of infectiousbronchitis virus genotypes in Western Europe from 2002 to2006rdquo Avian Pathology vol 37 no 3 pp 247ndash257 2008

[13] R M Irvine W J Cox V Ceeraz et al ldquoPoultry healthdetection of IBV QX in commercial broiler flocks in the UKrdquoVeterinary Record vol 167 no 22 pp 877ndash879 2010

[14] B Sigrist K Tobler M Schybli et al ldquoDetection of Aviancoronavirus infectious bronchitis virus type QX infection inSwitzerlandrdquo Journal of Veterinary Diagnostic Investigation vol24 no 6 pp 1180ndash1183 2012

[15] M M Lai and D Cavanagh ldquoThe molecular biology ofcoronavirusesrdquo Advances in Virus Research vol 48 pp 1ndash1001997

[16] M W Jackwood D Hall and A Handel ldquoMolecular evolutionand emergence of avian gammacoronavirusesrdquo Infection Genet-ics and Evolution vol 12 no 6 pp 1305ndash1311 2012

[17] B Hogue and C Machamer ldquoCoronavirus structural proteinsand virus assemblyrdquo in Nidoviruses pp 179ndash200 2008

[18] C A M de Haan and P J M Rottier ldquoMolecular interactionsin the assembly of coronavirusesrdquo Advances in Virus Researchvol 64 pp 165ndash230 2005

[19] D Cavanagh ldquoCoronavirus IBV structural characterization ofthe spike proteinrdquo Journal of General Virology vol 64 no 12pp 2577ndash2583 1983

[20] S Belouzard J K Millet B N Licitra and G R WhittakerldquoMechanisms of coronavirus cell entry mediated by the viralspike proteinrdquo Viruses vol 4 no 6 pp 1011ndash1033 2012

[21] J Ignjatovic and P G McWaters ldquoMonoclonal antibodies tothree structural proteins of avian infectious bronchitis viruscharacterization of epitopes and antigenic differentiation ofAustralian strainsrdquo Journal of General Virology vol 72 no 12pp 2915ndash2922 1991

[22] J Ignjatovic and S Sapats ldquoIdentification of previouslyunknown antigenic epitopes on the S and N proteins of avianinfectious bronchitis virusrdquo Archives of Virology vol 150 no 9pp 1813ndash1831 2005

[23] S Shen Z L Wen and D X Liu ldquoEmergence of a coronavirusinfectious bronchitis virus mutant with a truncated 3b genefunctional characterization of the 3b protein in pathogenesisand replicationrdquo Virology vol 311 no 1 pp 16ndash27 2003

[24] R CasaisMDavies D Cavanagh and P Britton ldquoGene 5 of theavian coronavirus Infectious bronchitis virus is not essential forreplicationrdquo Journal of Virology vol 79 no 13 pp 8065ndash80782005

[25] S Youn E W Collisson and C E Machamer ldquoContributionof trafficking signals in the cytoplasmic tail of the infectiousbronchitis virus spike protein to virus infectionrdquo Journal ofVirology vol 79 no 21 pp 13209ndash13217 2005

[26] P J M Rottier and J K Rose ldquoCoronavirus E1 glycoproteinexpressed from cloned cDNA localizes in the Golgi regionrdquoJournal of Virology vol 61 no 6 pp 2042ndash2045 1987

[27] L Jacobs B AMVanDer Zeijst andMCHorzinek ldquoCharac-terization and translation of transmissible gastroenteritis virusmRNAsrdquo Journal of Virology vol 57 no 3 pp 1010ndash1015 1986

[28] J K Locker G Griffiths M C Horzinek and P J M RottierldquoO-glycosylation of the coronavirus M protein Differentiallocalization of sialyltransferases in N- and O-linked glycosyla-tionrdquo The Journal of Biological Chemistry vol 267 no 20 pp14094ndash14101 1992

[29] C A M de Haan M de Wit L Kuo et al ldquoThe glycosylationstatus of the murine hepatitis coronavirus M protein affects theinterferogenic capacity of the virus in vitro and its ability toreplicate in the liver but not the brainrdquo Virology vol 312 no2 pp 395ndash406 2003

[30] K Narayanan A Maeda J Maeda and S Makino ldquoChar-acterization of the coronavirus M protein and nucleocapsidinteraction in infected cellsrdquo Journal of Virology vol 74 no 17pp 8127ndash8134 2000

[31] K R Hurst R Ye S J Goebel P Jayaraman and P SMasters ldquoAn interaction between the nucleocapsid protein anda component of the replicase-transcriptase complex is crucialfor the infectivity of coronavirus genomic RNArdquo Journal ofVirology vol 84 no 19 pp 10276ndash10288 2010

[32] J Jayaram S Youn and E W Collisson ldquoThe virion N proteinof infectious bronchitis virus is more phosphorylated than theN protein from infected cell lysatesrdquoVirology vol 339 no 1 pp127ndash135 2005

[33] SH Seo LWang R Smith andEWCollisson ldquoThe carboxyl-terminal 120-residue polypeptide of infectious bronchitis virusnucleocapsid induces cytotoxic T lymphocytes and protectschickens from acute infectionrdquo Journal of Virology vol 71 no10 pp 7889ndash7894 1997

[34] E W Collisson J Pei J Dzielawa and S H Seo ldquoCytotoxic Tlymphocytes are critical in the control of infectious bronchitisvirus in poultryrdquo Developmental amp Comparative Immunologyvol 24 no 2-3 pp 187ndash200 2000

[35] D Yu Z Han J Xu et al ldquoA novel B-cell epitope of avianinfectious bronchitis virus N proteinrdquo Viral Immunology vol23 no 2 pp 189ndash199 2010

[36] E Corse and C E Machamer ldquoThe cytoplasmic tails ofinfectious bronchitis virus E and M proteins mediate theirinteractionrdquo Virology vol 312 no 1 pp 25ndash34 2003

[37] L Wilson P Gage and G Ewart ldquoHexamethylene amilorideblocks E protein ion channels and inhibits coronavirus replica-tionrdquo Virology vol 353 no 2 pp 294ndash306 2006

[38] C-W Lee D A Hilt and M W Jackwood ldquoTyping of fieldisolates of infectious bronchitis virus based on the sequence of


the hypervariable region in the S1 generdquo Journal of VeterinaryDiagnostic Investigation vol 15 no 4 pp 344ndash348 2003

[39] J Ignjatovic and L Galli ldquoThe S1 glycoprotein but not theN or M proteins of avian infectious bronchitis virus inducesprotection in vaccinated chickensrdquoArchives of Virology vol 138no 1-2 pp 117ndash134 1994

[40] J G Zhu H D Qian Y L Zhang X G Hua and Z L WuldquoAnalysis of similarity of the S1 gene in infectious bronchitisvirus (IBV) isolates in Shanghai Chinardquo Archivos de MedicinaVeterinaria vol 39 no 3 pp 223ndash228 2007

[41] I Capua Z Minta E Karpinska et al ldquoCo-circulation of fourtypes of infectious bronchitis virus (793B 624I B1648 andMassachusetts)rdquo Avian Pathology vol 28 no 6 pp 587ndash5921999

[42] D Cavanagh K Mawditt P Britton and C J Naylor ldquoLon-gitudinal field studies of infectious bronchitis virus and avianpneumovirus in broilers using type-specific polymerase chainreactionsrdquo Avian Pathology vol 28 no 6 pp 593ndash605 1999

[43] W Jia K Karaca C R Parrish and S A Naqi ldquoA novel variantof avian infectious bronchitis virus resulting from recombina-tion among three different strainsrdquoArchives of Virology vol 140no 2 pp 259ndash271 1995

[44] M F Ducatez A M Martin A A Owoade et al ldquoCharacteri-zation of a new genotype and serotype of infectious bronchitisvirus inWestern Africardquo Journal of General Virology vol 90 no11 pp 2679ndash2685 2009

[45] E Domingo and J J Holland ldquoRNA virus mutations and fitnessfor survivalrdquoAnnual Review ofMicrobiology vol 51 pp 151ndash1781997

[46] T-H LimH-J Lee D-H Lee et al ldquoAn emerging recombinantcluster of nephropathogenic strains of avian infectious bronchi-tis virus in Koreardquo Infection Genetics and Evolution vol 11 no3 pp 678ndash685 2011

[47] J G Kusters E J Jager H G M Niesters and B A Mvan der Zeijst ldquoSequence evidence for RNA recombination infield isolates of avian coronavirus infectious bronchitis virusrdquoVaccine vol 8 no 6 pp 605ndash608 1990

[48] C Rowe S Baker M Nathan J Sgro A Palmenberg and JFleming ldquoQuasispecies development by high frequency RNArecombination during MHV persistencerdquo in Coronaviruses andArteriviruses pp 759ndash765 Springer US 1998

[49] W A Nix D S Troeber B F Kingham C L Keeler Jr and JGelb Jr ldquoEmergence of subtype strains of theArkansas serotypeof infectious bronchitis virus in Delmarva broiler chickensrdquoAvian Diseases vol 44 no 3 pp 568ndash581 2000

[50] S W Thor D A Hilt J C Kissinger A H Paterson andMW Jackwood ldquoRecombination in avian gamma-coronavirusinfectious bronchitis virusrdquo Viruses vol 3 no 9 pp 1777ndash17992011

[51] R A Gallardo V L van Santen andH Toro ldquoEffects of chickenanaemia virus and infectious bursal disease virus-inducedimmunodeficiency on infectious bronchitis virus replicationand genotypic driftrdquoAvian Pathology vol 41 no 5 pp 451ndash4582012

[52] S P Mondal and S A Naqi ldquoMaternal antibody to infec-tious bronchitis virus its role in protection against infectionand development of active immunity to vaccinerdquo VeterinaryImmunology and Immunopathology vol 79 no 1-2 pp 31ndash402001

[53] L Vervelde M G R Matthijs D A van Haarlem J J deWit and C A Jansen ldquoRapid NK-cell activation in chicken

after infection with infectious bronchitis virus M41rdquo VeterinaryImmunology and Immunopathology vol 151 no 3-4 pp 337ndash341 2013

[54] O Takeuchi and S Akira ldquoInnate immunity to virus infectionrdquoImmunological Reviews vol 227 no 1 pp 75ndash86 2009

[55] T Okabayashi H Kariwa S-I Yokota et al ldquoCytokine reg-ulation in SARS coronavirus infection compared to otherrespiratory virus infectionsrdquo Journal ofMedical Virology vol 78no 4 pp 417ndash424 2006

[56] J PeiM J Sekellick P IMarcus I-S Choi and EWCollissonldquoChicken interferon type I inhibits infectious bronchitis virusreplication and associated respiratory illnessrdquo Journal of Inter-feron amp Cytokine Research vol 21 no 12 pp 1071ndash1077 2001

[57] K Otsuki Y Sakagami and M Tsubokura ldquoSerological rela-tionship among ten strains of avian infectious bronchitis virusrdquoActa Virologica vol 31 no 2 pp 138ndash145 1987

[58] S Akira K Takeda and T Kaisho ldquoToll-like receptors crit-ical proteins linking innate and acquired immunityrdquo NatureImmunology vol 2 no 8 pp 675ndash680 2001

[59] MMiettinen T Sareneva I Julkunen and SMatikainen ldquoIFNsactivate toll-like receptor gene expression in viral infectionsrdquoGenes amp Immunity vol 2 no 6 pp 349ndash355 2001

[60] A M Kameka S Haddadi D S Kim S C Cork andM F Abdul-Careem ldquoInduction of innate immune responsefollowing infectious bronchitis corona virus infection in therespiratory tract of chickensrdquoVirology vol 450-451 pp 114ndash1212014

[61] F Cong X Liu Z Han Y Shao X Kong and S LiuldquoTranscriptome analysis of chicken kidney tissues followingcoronavirus avian infectious bronchitis virus infectionrdquo BMCGenomics vol 14 no 1 article 743 2013

[62] A Dar A Potter S Tikoo et al ldquoCpG oligodeoxynucleotidesactivate innate immune response that suppresses infectiousbronchitis virus replication in chicken embryosrdquo Avian Dis-eases vol 53 no 2 pp 261ndash267 2009

[63] X Guo A J M Rosa D-G Chen and X Wang ldquoMolecularmechanisms of primary and secondary mucosal immunityusing avian infectious bronchitis virus as a model systemrdquoVeterinary Immunology and Immunopathology vol 121 no 3-4 pp 332ndash343 2008

[64] J Guo D J Hui W C Merrick and G C Sen ldquoA new pathwayof translational regulation mediated by eukaryotic initiationfactor 3rdquoTheEMBO Journal vol 19 no 24 pp 6891ndash6899 2000

[65] J H Darbyshire and R W Peters ldquoHumoral antibody responseand assessment of protection following primary vaccination ofchicks with maternally derived antibody against avian infec-tious bronchitis virusrdquo Research in Veterinary Science vol 38no 1 pp 14ndash21 1985

[66] L F Caron ldquoEtiology and immunology of infectious bronchitisvirusrdquo Revista Brasileira de Ciencia Avicola vol 12 no 2 pp115ndash119 2010

[67] S H Seo J Pei W E Briles J Dzielawa and E W CollissonldquoAdoptive transfer of infectious bronchitis virus primed 120572120573 Tcells bearing CD8 antigen protects chicks from acute infectionrdquoVirology vol 269 no 1 pp 183ndash189 2000

[68] L M Timms and C D Bracewell ldquoCell mediated and humoralimmune response of chickens to live infectious bronchitisvaccinesrdquo Research in Veterinary Science vol 31 no 2 pp 182ndash189 1981

[69] M A Johnson C Pooley J Ignjatovic and S G Tyack ldquoArecombinant fowl adenovirus expressing the S1 gene of infec-tious bronchitis virus protects against challenge with infectious


bronchitis virusrdquo Vaccine vol 21 no 21-22 pp 2730ndash27362003

[70] J Pardo A Bosque R Brehm et al ldquoApoptotic pathways areselectively activated by granzymeA andor granzyme B in CTL-mediated target cell lysisrdquo The Journal of Cell Biology vol 167no 3 pp 457ndash468 2004

[71] R S Gurjar S L Gulley and F W van Ginkel ldquoCell-mediatedimmune responses in the head-associated lymphoid tissuesinduced to a live attenuated avian coronavirus vaccinerdquo Devel-opmental and Comparative Immunology vol 41 no 4 pp 715ndash722 2013

[72] R Meir S Krispel L Simanov D Eliahu O Maharat and JPitcovski ldquoImmune responses to mucosal vaccination by therecombinant S1 and N proteins of infectious bronchitis virusrdquoViral Immunology vol 25 no 1 pp 55ndash62 2012

[73] D Cavanagh ldquoSevere acute respiratory syndrome vaccinedevelopment experiences of vaccination against avian infec-tious bronchitis coronavirusrdquoAvian Pathology vol 32 no 6 pp567ndash582 2003

[74] D King and D Cavanagh ldquoInfectious bronchitisrdquo Diseases ofPoultry vol 9 pp 471ndash484 1991

[75] H J Lee H N Youn J S Kwon et al ldquoCharacterizationof a novel live attenuated infectious bronchitis virus vaccinecandidate derived from a Korean nephropathogenic strainrdquoVaccine vol 28 no 16 pp 2887ndash2894 2010

[76] J Sasipreeyajan T Pohuang and N Sirikobkul ldquoEfficacy ofdifferent vaccination programs against thai QX-like infectiousbronchitis virusrdquo Thai Journal of Veterinary Medicine vol 42no 1 pp 73ndash79 2012

[77] A Vagnozzi M Garcıa S M Riblet and G Zavala ldquoProtectioninduced by infectious laryngotracheitis virus vaccines aloneand combined with Newcastle disease virus andor infectiousbronchitis virus vaccinesrdquo Avian Diseases vol 54 no 4 pp1210ndash1219 2010

[78] I Tarpey S J Orbell P Britton et al ldquoSafety and efficacyof an infectious bronchitis virus used for chicken embryovaccinationrdquo Vaccine vol 24 no 47-48 pp 6830ndash6838 2006

[79] G Bijlenga J K A Cook J Gelb Jr and J J De WitldquoDevelopment and use of the H strain of avian infectiousbronchitis virus from the Netherlands as a vaccine a reviewrdquoAvian Pathology vol 33 no 6 pp 550ndash557 2004

[80] Y Zhang H-N Wang T Wang et al ldquoComplete genomesequence and recombination analysis of infectious bronchitisvirus attenuated vaccine strain H120rdquo Virus Genes vol 41 no3 pp 377ndash388 2010

[81] S-W Lee P F Markham M J C Coppo et al ldquoAttenuatedvaccines can recombine to form virulent field virusesrdquo Sciencevol 337 no 6091 p 188 2012

[82] M G R Matthijs A Bouma F C Velkers J H H van Eckand J A Stegeman ldquoTransmissibility of infectious bronchitisvirus H120 vaccine strain among broilers under experimentalconditionsrdquo Avian Diseases vol 52 no 3 pp 461ndash466 2008

[83] P S Masters and P J M Rottier ldquoCoronavirus reverse geneticsby targeted RNA recombinationrdquo Current Topics in Microbiol-ogy and Immunology vol 287 pp 133ndash159 2005

[84] Y S Zhou Y Zhang H N Wang et al ldquoEstablishment ofreverse genetics system for infectious bronchitis virus attenu-ated vaccine strain H120rdquo Veterinary Microbiology vol 162 no1 pp 53ndash61 2013

[85] P Finney P Box and H Holmes ldquoStudies with a bivalentinfectious bronchitis killed virus vaccinerdquo Avian Pathology vol19 no 3 pp 435ndash450 1990

[86] B S Ladman C R Pope A F Ziegler et al ldquoProtection ofchickens after live and inactivated virus vaccination againstchallenge with nephropathogenic infectious bronchitis virusPAWolgemuth98rdquo Avian Diseases vol 46 no 4 pp 938ndash9442002

[87] J K A Cook M Jackwood and R C Jones ldquoThe long view 40years of infectious bronchitis researchrdquoAvian Pathology vol 41no 3 pp 239ndash250 2012

[88] N Tatsis and H C J Ertl ldquoAdenoviruses as vaccine vectorsrdquoMolecular Therapy vol 10 no 4 pp 616ndash629 2004

[89] C-S Song Y-J Lee C-W Lee et al ldquoInduction of protectiveimmunity in chickens vaccinated with infectious bronchitisvirus S1 glycoprotein expressed by a recombinant baculovirusrdquoJournal of General Virology vol 79 no 4 pp 719ndash723 1998

[90] O B Faulkner C Estevez Q Yu and D L Suarez ldquoPassiveantibody transfer in chickens to model maternal antibodyafter avian influenza vaccinationrdquo Veterinary Immunology andImmunopathology vol 152 no 3-4 pp 341ndash347 2013

[91] M T Dertzbaugh ldquoGenetically engineered vaccines anoverviewrdquo Plasmid vol 39 no 2 pp 100ndash113 1998

[92] X-M Shi Y Zhao H-B Gao et al ldquoEvaluation of recombinantfowlpox virus expressing infectious bronchitis virus S1 geneand chicken interferon-120574 gene for immune protection againstheterologous strainsrdquoVaccine vol 29 no 8 pp 1576ndash1582 2011

[93] H-Y Chen M-F Yang B-A Cui et al ldquoConstruction andimmunogenicity of a recombinant fowlpox vaccine coexpress-ing S1 glycoprotein of infectious bronchitis virus and chickenIL-18rdquo Vaccine vol 28 no 51 pp 8112ndash8119 2010

[94] Z Xiang G Gao A Reyes-Sandoval Y Li J Wilson andH Ertl ldquoOral vaccination of mice with adenoviral vectors isnot impaired by preexisting immunity to the vaccine carrierrdquoJournal of Virology vol 79 no 6 p 3888 2005

[95] M W Jackwood ldquoCurrent and future recombinant viral vac-cines for poultryrdquo Advances in Veterinary Medicine vol 41 pp517ndash522 1999

[96] L Wang R L Parr D J King and E W Collisson ldquoA highlyconserved epitope on the spike protein of infectious bronchitisvirusrdquo Archives of Virology vol 140 no 12 pp 2201ndash2213 1995

[97] N Promkuntod R E W van Eijndhoven G de VriezeA Grone and M H Verheije ldquoMapping of the receptor-binding domain and amino acids critical for attachment in thespike protein of avian coronavirus infectious bronchitis virusrdquoVirology vol 448 pp 26ndash32 2014

[98] T Yang H-N Wang X Wang et al ldquoThe protective immuneresponse against infectious bronchitis virus induced by multi-epitope based peptide vaccinesrdquo Bioscience Biotechnology andBiochemistry vol 73 no 7 pp 1500ndash1504 2009

[99] H-P Cao H-N Wang A-Y Zhang et al ldquoExpression ofavian infectious bronchitis virus multi-epitope based peptideEpiC in Lactococcus lactis for oral immunization of chickensrdquoBioscience Biotechnology and Biochemistry vol 76 no 10 pp1871ndash1876 2012

[100] H-P Cao H-N Wang X Yang et al ldquoLactococcus lactisanchoring avian infectious bronchitis virus multi-epitope pep-tide EpiC induced specific immune responses in chickensrdquoBioscience Biotechnology and Biochemistry vol 77 no 7 pp1499ndash1504 2013

[101] S Moreno and M Timon ldquoDNA vaccination an immunologi-cal perspectiverdquo Inmunologia vol 23 no 1 pp 41ndash55 2004

[102] M A Liu ldquoDNA vaccines an historical perspective and viewto the futurerdquo Immunological Reviews vol 239 no 1 pp 62ndash842011


[103] D R Kapczynski D A Hilt D Shapiro H S Sellers andMWJackwood ldquoProtection of chickens from infectious bronchitisby in ovo and intramuscular vaccination with a DNA vaccineexpressing the S1 glycoproteinrdquo Avian Diseases vol 47 no 2pp 272ndash285 2003

[104] L Tian H-N Wang D Lu Y-F Zhang T Wang and R-MKang ldquoThe immunoreactivity of a chimericmulti-epitopeDNAvaccine against IBV in chickensrdquo Biochemical and BiophysicalResearch Communications vol 377 no 1 pp 221ndash225 2008

[105] M Tang H Wang S Zhou and G Tian ldquoEnhancement of theimmunogenicity of an infectious bronchitis virus DNA vaccineby a bicistronic plasmid encoding nucleocapsid protein andinterleukin-2rdquo Journal of Virological Methods vol 149 no 1 pp42ndash48 2008

[106] B Tan H Wang L Shang and T Yang ldquoCoadministrationof chicken GM-CSF with a DNA vaccine expressing infectiousbronchitis virus (IBV) S1 glycoprotein enhances the specificimmune response and protects against IBV infectionrdquo Archivesof Virology vol 154 no 7 pp 1117ndash1124 2009

[107] F Yan Y Zhao Y Hu et al ldquoProtection of chickens againstinfectious bronchitis virus with a multivalent DNA vaccineand boosting with an inactivated vaccinerdquo Journal of VeterinaryScience vol 14 no 1 pp 53ndash60 2013

[108] M-J Tang H-N Wang S Zhou Y Huang and P Liu ldquoPotentimmune responses elicited by a bicistronic IBV DNA vaccineexpressing S1 and IL-2 generdquo Wei Sheng Wu Xue Bao vol 47no 6 pp 1055ndash1059 2007

[109] L Haygreen F Davison and P Kaiser ldquoDNA vaccines forpoultry the jump from theory to practicerdquo Expert Review ofVaccines vol 4 no 1 pp 51ndash62 2005

[110] D Cavanagh R Casais M Armesto et al ldquoManipulationof the infectious bronchitis coronavirus genome for vaccinedevelopment and analysis of the accessory proteinsrdquo Vaccinevol 25 no 30 pp 5558ndash5562 2007

[111] P Britton M Armesto D Cavanagh and S Keep ldquoModifi-cation of the avian coronavirus infectious bronchitis virus forvaccine developmentrdquo Bioengineered Bugs vol 3 no 2 pp 114ndash119 2012

[112] R Casais B Dove D Cavanagh and P Britton ldquoRecombinantavian infectious bronchitis virus expressing a heterologousspike gene demonstrates that the spike protein is a determinantof cell tropismrdquo Journal of Virology vol 77 no 16 pp 9084ndash9089 2003

[113] MArmesto S Evans D Cavanagh A-B Abu-Median S Keepand P Britton ldquoA recombinant Avian infectious bronchitis virusexpressing a heterologous spike gene belonging to the 491serotyperdquo PLoS ONE vol 6 no 8 Article ID e24352 2011

[114] T Hodgson R Casais B Dove P Britton and D CavanaghldquoRecombinant infectious bronchitis coronavirus Beaudettewiththe spike protein gene of the pathogenic M41 strain remainsattenuated but induces protective immunityrdquo Journal of Virol-ogy vol 78 no 24 pp 13804ndash13811 2004

[115] F M Tomley A P Mockett M E Boursnell et al ldquoExpressionof the infectious bronchitis virus spike protein by recombinantvaccinia virus and induction of neutralizing antibodies invaccinated micerdquo Journal of General Virology vol 68 part 9 pp2291ndash2298 1987

[116] F M F Tomley ldquoRecombinant vaccines for poultryrdquo Vaccinevol 9 no 1 pp 4ndash5 1991

[117] J-Y Zhou J-XWu L-Q Cheng et al ldquoExpression of immuno-genic S1 glycoprotein of infectious bronchitis virus in transgenic

potatoesrdquo Journal of Virology vol 77 no 16 pp 9090ndash90932003

[118] J Zhang X-W Chen T-Z Tong Y Ye M Liao and H-YFan ldquoBacMam virus-based surface display of the infectiousbronchitis virus (IBV) S1 glycoprotein confers strong protectionagainst virulent IBV challenge in chickensrdquo Vaccine vol 32 no6 pp 664ndash670 2014

[119] H Jiao Z Pan Y Yin S Geng L Sun and X Jiao ldquoOral andnasal DNA vaccines delivered by attenuated Salmonella entericaserovar typhimurium induce a protective immune responseagainst infectious bronchitis in chickensrdquo Clinical and VaccineImmunology vol 18 no 7 pp 1041ndash1045 2011

[120] L H L Lua N K Connors F Sainsbury Y P Chuan NWibowo and A P J Middelberg ldquoBioengineering virus-likeparticles as vaccinesrdquo Biotechnology and Bioengineering vol 111no 3 pp 425ndash440 2014

[121] L Lv X Li G Liu et al ldquoProduction and immunogenicityof chimeric virus-like particles (VLPs) containing the spike(S1) glycoprotein of infectious bronchitis virusrdquo Journal ofVeterinary Science vol 15 no 2 pp 209ndash216 2014

Submit your manuscripts athttpwwwhindawicom

Stem CellsInternational

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014


MEDIATORSINFLAMMATION

of


Behavioural Neurology

EndocrinologyInternational Journal of



Disease Markers


BioMed Research International

OncologyJournal of



Oxidative Medicine and Cellular Longevity


PPAR Research

The Scientific World JournalHindawi Publishing Corporation httpwwwhindawicom Volume 2014

Immunology ResearchHindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Journal of

ObesityJournal of



Computational and Mathematical Methods in Medicine

OphthalmologyJournal of


Diabetes ResearchJournal of



Research and TreatmentAIDS


Gastroenterology Research and Practice


Parkinsonrsquos Disease

Evidence-Based Complementary and Alternative Medicine

Volume 2014Hindawi Publishing Corporationhttpwwwhindawicom


(a) (b)

Figure 1 Predicted 3-dimensional structure of S1-glycoprotein (a) and nucleocapsid protein (b) determinants of Massachusetts strain of avianinfectious bronchitis virus Structures are drawn using SWISS homology modeller available online at httpswissmodelexpasyorg

as M41 Ma5 Ark and Conn and Netherlands for exampleH52 and H120 as well as European strains such as 793BCR88 and D274 However studies have shown that vaccinesagainst these strains often lead to poor immune responseespecially against local strains Live attenuated IB vaccineshave also been shown to contribute to the emergence of newpathogenic IBV variants [7 8] Notably changes in geograph-ical distribution and tissue tropism have been observed inQX-like strains that initially emerged in China and spreadto cause great economic loss to poultry farmers in Asia[9] Russia [10] and Europe [11ndash14] This review is aimedat describing progress and challenges associated with IBVvaccine development Some aspects of viral-induced immuneresponses are discussed

2 Review

21 Aetiology and Genome Characteristics Avian infectiousbronchitis virus (IBV) together with Turkey coronavirus andBeluga whale coronavirus belongs to a Gammacoronavirussubgroup familyCoronaviridae orderNidovirales Althoughantigenically different members of Coronaviridae familysuch as SARS and MERS coronavirus share common struc-tural protein organisation Coronaviruses genome ismade upof a single stranded enveloped RNA that measures from 27 to32 kbmaking them the largest of theRNAviruses [15] Partic-ularly IBVgenomehas an average diameter of 80ndash120 nmanda typically large club of 20 nm with heavily glycosylated spikeprojections Four different genes encoding for the structuralproteins are found in IBV genome These are designated asspike (S) envelope (E) matrix (M) and nucleocapsid (N)The structural protein genes are also interspaced by genescoding for nonstructural and accessory proteins arranged inthe order of 51015840 to 31015840 directions as UTR-1a1ab-S3a-3b-E-M5a-5b-N-31015840-UTR-poly(A) [16] Of the structural protein genesthe S1 and N proteins contain epitopes responsible for hostimmune response (Figure 1)

22 Spike Glycoprotein The S-protein is heavily glycosylatedtransmembrane protein that spanned from 1160 amino

acids giving rise to 150ndash200 kDa It possessed a cleavedsignal sequence one transmembrane domain and a shortC-terminal tail [17] IBV S-protein is made up of 3400nucleotides posttranslationally cleaved into S1 (520 AASresidue) at the amino terminal and S2 (625 AAS residue)at the carboxyl terminal The two glycosylated proteins(S1 and S2) are anchored in the hydrophobic region nearthe carboxylic part of the S2 and cleaved by furin or itsrelated enzymes in the Golgi complex [18 19] Typically S1-glycoprotein plays a role in receptor binding while the S2contributes aids in the fusion of the virus [20] Of the twoS-glycoprotein genes the S1-gene is the important immuno-genic component and contained epitopes responsible forneutralizing antibody [21 22] It also determines receptorbinding as well as membrane fusion via virus-to-cell and cell-to-cell interactions [20]

23 The Nonstructural Genesrsquo 3a 3b 5a and 5b Proteins TheIBV genome possesses two small nsp genes 3 and 5 thatexpress three (3a 3b and 3c [E]) and two (5a and 5b) geneproducts respectively The 3a 3b 5a and 5b proteins of IBVshow a unique sequence characteristic when compared tomembers of group I and II coronaviruses [23] Although thespecific function of small protein remains unknown thesegenes are thought to contribute to virus virulence [23 24]Studies on the function of 5a-ns segment using reversegenetics have identified a possible link between ns-proteinand virus virulence however their contribution to virusreplication may be less relevant [25]

24 Matrix Protein The coronavirus matrix protein (M-protein) slightly protrudes to the surface and is situatedbetween 220 and 262 aa which is glycosylated on the N-terminal domain [26] Although members of group 2 coro-navirus are O-glycosylated IBV and members of group 1coronaviruses are glycosylatedwithN-linked oligosaccharidemolecules [27] The role of glycosylation of M-protein isstill not clear however using the MHV model it wasfound that cell infectedwithMHVcontainingN-glycosylated







100

100

100

100

100

589

90

516

712709

567

507549

715922

68

917612

100

88

9555

995

985100 Florida

Conn32062ConnCvial2

M41-1979EgyptF03

AIBV-H52AIBV-H120


IBV-NGADMV564206

THA001V904

MH536595TX94aTX94b|



QXIBVAIBV-LX4LH2

SDLY0612THA80151

711

006

M41|GQ219712

HNSG|GQ154654





































IB vaccines

Killed


antibody mediated)


chemical adjuvants

Required

frequent

vaccinations

Time-consuming



virulence



DNA


advances


require



alter some protein

due tomultiple

booster

byvaccines

may(only


Neutralization

carrier











6 Conclusion









Acknowledgments


References







































































































































of






Disease Markers



OncologyJournal of





PPAR Research



Journal of

ObesityJournal of






















100

100

100

100

100

589

90

516

712709

567

507549

715922

68

917612

100

88

9555

995

985100 Florida

Conn32062ConnCvial2

M41-1979EgyptF03

AIBV-H52AIBV-H120


IBV-NGADMV564206

THA001V904

MH536595TX94aTX94b|



QXIBVAIBV-LX4LH2

SDLY0612THA80151

711

006

M41|GQ219712

HNSG|GQ154654





































IB vaccines

Killed


antibody mediated)


chemical adjuvants

Required

frequent

vaccinations

Time-consuming



virulence



DNA


advances


require



alter some protein

due tomultiple

booster

byvaccines

may(only


Neutralization

carrier











6 Conclusion









Acknowledgments


References







































































































































of






Disease Markers



OncologyJournal of





PPAR Research



Journal of

ObesityJournal of


















































IB vaccines

Killed


antibody mediated)


chemical adjuvants

Required

frequent

vaccinations

Time-consuming



virulence



DNA


advances


require



alter some protein

due tomultiple

booster

byvaccines

may(only


Neutralization

carrier











6 Conclusion









Acknowledgments


References







































































































































of






Disease Markers



OncologyJournal of





PPAR Research



Journal of

ObesityJournal of








































IB vaccines

Killed


antibody mediated)


chemical adjuvants

Required

frequent

vaccinations

Time-consuming



virulence



DNA


advances


require



alter some protein

due tomultiple

booster

byvaccines

may(only


Neutralization

carrier











6 Conclusion









Acknowledgments


References







































































































































of






Disease Markers



OncologyJournal of





PPAR Research



Journal of

ObesityJournal of





























IB vaccines

Killed


antibody mediated)


chemical adjuvants

Required

frequent

vaccinations

Time-consuming



virulence



DNA


advances


require



alter some protein

due tomultiple

booster

byvaccines

may(only


Neutralization

carrier











6 Conclusion









Acknowledgments


References







































































































































of






Disease Markers



OncologyJournal of





PPAR Research



Journal of

ObesityJournal of

















IB vaccines

Killed


antibody mediated)


chemical adjuvants

Required

frequent

vaccinations

Time-consuming



virulence



DNA


advances


require



alter some protein

due tomultiple

booster

byvaccines

may(only


Neutralization

carrier











6 Conclusion









Acknowledgments


References







































































































































of






Disease Markers



OncologyJournal of





PPAR Research



Journal of

ObesityJournal of



















6 Conclusion









Acknowledgments


References







































































































































of






Disease Markers



OncologyJournal of





PPAR Research



Journal of

ObesityJournal of

















































































































































of






Disease Markers



OncologyJournal of





PPAR Research



Journal of

ObesityJournal of















































































































of






Disease Markers



OncologyJournal of





PPAR Research



Journal of

ObesityJournal of













































































of






Disease Markers



OncologyJournal of





PPAR Research



Journal of

ObesityJournal of










































of






Disease Markers



OncologyJournal of





PPAR Research



Journal of

ObesityJournal of





















of






Disease Markers



OncologyJournal of





PPAR Research



Journal of

ObesityJournal of
















Documents

Review Article Progress and Challenges toward the