Introducere in Imunologie UMF Nov 2012

Aurora Salageanu

Laborator Imunitate AntiinfectioasaInstitutul Cantacuzino

Imunitate innascuta vs. Imunitate dobindita

Recunoasterea agentului patogen

Rolul si functiile imunitatii innascute

Raspunsul imun anti-bacterian

Sistemul imun

adaptat dupa“Microbiology and Immunology on-line”, University of South California, School of Medicinehttp://pathmicro.med.sc.edu/book/immunol-sta.htm

SISTEM IMUN

Imunitateinnascuta

(prima linie de aparare)

Imunitatedobindita

(a II-a linie de aparare)

Componente celulare

Componente umorale

Componente celulare

Componente umorale

Celulele sistemului imun

preluat din “Microbiology and Immunology on-line”, University of South California, School of Medicinehttp://pathmicro.med.sc.edu/book/immunol-sta.htm

preluat din “Microbiology and Immunology on-line”, University of South California, School of Medicinehttp://pathmicro.med.sc.edu/book/immunol-sta.htm

Tesutul limfoid

preluat din “Microbiology and Immunology on-line”, University of South California, School of Medicine

http://pathmicro.med.sc.edu/book/immunol-sta.htm

Distributia organelorlimfoide

Circulatia limfocitelor in organele limfoide periferice

preluat din “Microbiology and Immunology on-line”, University of South California, School of Medicinehttp://pathmicro.med.sc.edu/book/immunol-sta.htm

preluat din “Microbiology and Immunology on-line”, University of South California, School of Medicinehttp://pathmicro.med.sc.edu/book/immunol-sta.htm

Raspunsul imun fata de patogeni

Raspunsul imun fata de patogeni

IMUNITATE INNASCUTA

Disponibila in orice moment

(innascuta)

Intra in actiune imediat (in citeva ore) dupa

expunere la antigen

Raspuns initial pentru: • eliminare microbi • prevenire infectii

IMUNITATE INNASCUTA

Mecanism universal de aparare fata de infectii

Prima linie de aparare a organismului

Precede raspunsul imun adaptativ

prezent la toate organismele pluricelulare

receptori si efectori ancestrali

raspunde la o mare varietate de patogeni

Distinctie perfecta self-nonself

Defecte foarte rare si in general letale

IMUNITATE INNASCUTA

preluat din Janeway, CA, Travers, P, Walport M, Shlomchik M “Immunobiology“, New York and London: Garland Science; c20http://www.ncbi.nlm.nih.gov/sites/entrez?db=books

IMUNITATEA INNASCUTA este importanta!

IMUNITATE

raspuns independent de antigen

receptori pt. patogeni:

codificati in genom

specificitate joasa

raspuns imediat

lipsa memorie

prezenta la toate organismelepluricelulare

raspuns dependent de antigen

receptori pt. patogeni:

generati (rearanjare genica)

specificitate inalta

raspuns lent

memorie imunologica

(expansiune clonala ly)

prezenta doar la vertebrate

SISTEM INTEGRAT

INNASCUTA / nespecifica(innate immunity)

DOBINDITA / specifica(adaptive immunity)

Fiecare limfocit: un singur receptor (specificitate unica)

Interactia receptor-ligand activarea limfocitului

Celulele efectoare diferentiate dint-un limfocit activat:

acelasi receptor

Limfocitele cu receptori self sunt eliminate (toleranta)

Specificitatea raspunsului imun adaptativTeoria selectiei clonale

ROL SI FUNCTII

Recunoastere

Functii efectoare

• prevenire intrare

• eliminare

Rol “instructiv” asupra imunitatii specifice

Innate immunity

microorganisme patogene

initierea si tipul raspunsului

originea si contextul atg

ELEMENTE CONSTITUTIVE

1. Bariere anatomice

2. Componente moleculare

3. Componente celulare

Innate immunity

Factori fizici / mecanici

1. Bariere anatomice- piele- mucoase

Innate immunity

• Functia de prevenire a intrarii microorganismelor patogene

Factori chimici

Factori biologici

• motilitate: muco-ciliara, peristaltica• mucus• fluxul fluidelor prin organism

• pH • molecule antimicrobiene

• limfocite T intraepiteliale ()• celule B-1

2. Componente moleculare- receptori- molecule secretate

Innate immunity

Functia de recunoastere

Functii efectorii

Mol. anorganice: HCl, NO, H2O2

Peptide antibacteriene: defensine, cathelicidine, histatineProteine antibacteriene: lizozim, lactoferina, transferinaLectine: colectine, ficoline, receptori manozaComplementCitokine: IFN-/, IL-1, TNF-, CSFChemokine: IL-8, MIP, MCPReceptori TLR

3. Componente celulare

Innate immunity

• Functia de eliminare a microorganismelor patogene

celule NK

Fagocitoza

Inflamatie

Citotoxicitate

neutrofile monocite/macrofagecelule dendritice

bazofilemastociteeozinofile

RECEPTORI

Recunoastere imuna

INNASCUTA(innate immunity)

codificati in genom

distributie non-clonala

recunosc structuriconservate

DOBINDITA(adaptive immunity)

generati prin rearanjare genica

distributie clonala(expansiune clonala ly)

recunosc detalii de structura moleculara(epitopi)

Recunoastere imuna

Ipoteze

selfnon-self

origine antigen / context biologic

Receptori (self vs. nonself microbian)

(Medzhitov & Janeway, 1997)

Semnale de pericol “Danger hypothesis”

(self vs. self alterat)

(Polly Matzinger, 1994)

Recunoastere “prin lipsa”(‘‘missing self”)

Recunoastere imuna

Ipoteze

Receptori (self vs. nonself microbian)

PRR Pattern Recognition Receptor

PAMP Pathogen Associated Molecular Pattern(Medzhitov & Janeway, 1997)

PAMP

invariabile inalt conservate specifice microbilor

(patogeni + nonpatogeni) comune pentru o clasa de microbi vitale pentru microorganisme

•lipopolizaharid •peptidoglican•acid lipoteichoic•lipoproteine•manoza•ADN•ARN dc•flagelina•pilina•zimozan

Gram-negative Gram-positive

Pattern Recognition Receptors - PRR

Endocytic PRRs• glycosylphosphatidylinositol (gpi)-linked receptor• Scavenger receptors (SR)• C-type lectin receptors (CLR)

LPS

oxLDL; microbes Microbes; microbial moieties

Signaling PRRs• Toll-like receptors (TLR)

• NOD-like receptors (NLR)

• RIG1-like helicases (RLH)

Microbial moieties

Bacterial lipoproteins

Nucleic acids

Bridging molecules

• Collectins

• Ficolins

• Pentraxins

Sugars

Glycoproteins

Microbes; microbial moieties

(adaptat dupa Jeannin et al. “Pattern recognition receptors in the immune response againstdying cells”, Current Opinion in Immunology 2008, 20:1–8)

Pattern Recognition Receptors - PRR

a) ENDOCITOZA Endocytic PRRs

proteina bact.

receptori manoza(lectina C)

FAGOCIT

receptori scavenger(CD36, CD68, SRB-1)

C3bglicoproteina

bact.

receptori opsonine(CR1)

Bacterie

LPS, LTAman

Pattern Recognition Receptors - PRR

b) TRANSMITERE SEMNAL Signaling PRRs

TLRToll-like receptors

NODnucleotide-binding oligomerization domain

RIG-1retinoic acid-inducible gene-1

Toll-like receptors (TLR) proteine transmembranare tip I conservate filogenetic (Drosophila om) domeniu extracelular bogat in leucina domeniu intracelular TIR (similar IL-1R) TLR mamifere (11-om, 13-soarece):

recunoastere PAMPs asociere cu alti TLR sau alte proteine (MD2,CD14)

Lipoproteins, lipopeptidesPeptidoglycanZymosanLPS Leptospira interrogans LPS P.gingivalisGPI (T.cruzi)LipoarabinomannanPhosphatidylinositol dimannoside(M. tuberculosis)

TLR2+(TLR1/TLR6)

LPS

Taxol

HSP60

Fibronectin

F Protein (RSV)

Flagellin CpG DNA

TLR4 TLR5 TLR9

TLR

Rol “instructiv” asupra imunitatii specifice

Infectie

Insecte MamifereNFkB

• Peptide antimicrobiene• iNOS (soarece)• Molecule costimulatoare• Citokine proinflamatorii

Peptide antimicrobiene

SpatzleToll

PAMP

PAMP

dorsal

TLR

TLR: semnalizare intracelulara

Receptori (self vs. nonself microbian)

(Medzhitov & Janeway, 1997)

Semnale de pericol “Danger hypothesis”

(self vs. self alterat)

(Polly Matzinger, 1994)

IPOTEZE

Recunoastere imuna

Danger hypothesis

Danger signal

Naive

T cells

APC

Normal cell

Damaged cell

Signal 1 Signal 2 (costimulation)

- infection- tissue damage- stress cells- hypoxia- temperature shifts- hsp

Recunoastere imunaIPOTEZE

- Receptori

(Medzhitov & Janeway, 1997)

- Semnale de pericol (“danger hypothesis”)

(Polly Matzinger, 1994)

- Recunoastere “prin lipsa”(‘‘missing self”)

CelulaNK

Celulatinta

CelulaNK

Celulatinta

Absenta citotoxicitatii

Citotoxicitate

NKR

NCR Ligand activator

MHC cls I

NKR

NCR Ligand activator

Missing self

ROL SI FUNCTII

Recunoastere

Functii efectoare

Innate immunity

microorganisme patogene

•prevenire intrare

•eliminare

Functiile imunitatii innascute

PAMP

Stimulare PRR stimuleaza fagocitoza

induce activitate microbicida

induce citokine inflamatorii:

IL-1, IL-6, TNF- (NF-kB)

activeaza imunitatea dobindita

expresia mol. costim. (MHC cls.II, CD80/CD86)

Functii efectorii: Fagocitoza

Distrugerea

Ingerarea

Atasarea

microorganisme patogeneChemotaxianeutrofileeosinofilemonocitemacrofagecelule dendriticelimfocite B

celule fagocitare

Fagocitoza

independent de oxigendependent de oxigen

Mecanism

- defensine- cathepsina B- lizozim- lactoferina- enzime proteolitice

O2–

H2 O2

1O2

OClOH

Rol• eliminare a microorganismelor patogene

• prelucrare atg pt. prezentare

Inflamatia

permeabilitate capilara

expresia mol. adeziune cel. endoteliale

diapedeza

- citokine pro-inflamatorii (TNF-, IL-1) PAMP / PRR

- vasodilatatoare- complement- bradikinine

Citokine Macrofag activat

IL-1

- activeaza endoteliul vascular

- activeaza ly- acces cel. efect.

- activeaza endoteliul vascular

- creste permeab. vasculara

- acces cel. efect.

- activeaza ly- producere atc.

- activeaza NK- induce dif. Th1

TNF- IL-6 IL-12

EFECTE LOCALE

EFECTE SISTEMICE- febra- producere de IL-6

- febra- mobilizare metaboliti- soc

- febra- inducere proteine

faza acuta

Chemokine proteine masa moleculara mica (8-12 kDa) rol: inflamatie, reglare raspuns imun, angiogeneza, hematopoieza,

interactie cu SNC 4 Cys pozitie conservata (punti disulfidice) structura tertiara caracteristica (1- 3, ) redundanta (receptori si celule)

CXC

monocite limfocite limfociteneutrofile

CC C CXXXC

IL-8-mo/m-fibroblaste-cel.endoteliale

NAP-2-plachete

IP-10-fibroblaste-endoteliu

SDF-1-celule stromale

MCP-1

MIP-1,

RANTES

MDC- mo/m- fibroblaste- cel.endoteliale- cel.epiteliale etc

FRAKTALKINALIMFOTAKTINA

Functii efectorii: Rolul interferon

IFN-/

Celula infectata viral Celula neinfectata

IFN receptor

2-5 (A) Sintetaza PKR

Inhibare sinteza proteica

degradare mRNA translatie mRNA

ROL SI FUNCTII

Recunoastere

Functii efectoare

• prevenire intrare

• eliminare

Rol “instructiv” asupra imunitatii specifice

Innate immunity

initierea si tipul raspunsului

APC

TLR

T cell

PAMP

costimulator

CD28

MHC / peptide

TCR

Infectie

Activare

Co-stimulare: initierea raspunsului imun specific

(adapted after Medzhitov R, Nature Reviews Immunology, 1, 2001, 135-145)

PAMP

TLR

pathogen

Endocytic PRR

Naive

T cells

CD80/86

Th1

IFN-

CD28

MHC-II TCR

IL-12

DC

Th1

IFN-

INNATE IMMUNITY

ADAPTIVE IMMUNITYcellular immune response

Celule dendritice umane diferentiate din monocite izolate din singele periferic

Laborator Imunitate Antiinfectioasa, INCDMI “Cantacuzino”, 2006

NIPC = Natural Interferon-Producing Cell

Immature DC Mature DC

INFECTIE VIRALA

IFN-/

Citokine imunoreglatoare: orientarea raspunsului imun specific

(Plasmacytoid precursor dendritic cells)

1/500 – 1/200 din celulelemononucleare din singele priferic Produc de 1000x mai mult IFN decitalte celule si cantitati mari de TNF• Recognition mechanism: probably TLR7, TLR9• Functie? Imunitate innascuta anti-virala; stimulare im adaptativa ?

Nu este doar un sistem de aparare simplu, menit sa tina in loc infectia pina la interventia imunitatii dobindite

“Instruieste” sistemul imunitatii dobindite pentru a raspunde la infectii

Decizia majora de a raspunde sau nu unui antigen este luata de

imunitatea innascuta, prin receptorii codificati in genom !

Imunitate innascuta

The Nobel Prize in Physiology or Medicine 2011 was divided, one half jointly to Bruce A. Beutler and Jules A. Hoffmann

"for their discoveries concerning the activation of innate immunity"

and the other half to Ralph M. Steinman

"for his discovery of the dendritic cell and its role in adaptive immunity"

The Nobel Prize in Physiology or Medicine 2011http://www.nobelprize.org/nobel_prizes/medicine/laureates/2011/advanced-medicineprize2011.pdf

Raspunsul imun fata de patogeni

CELULE “SANTINELA”: celule dendritice imature, macrofage, mastocite

- recunosc antigenul (infectia)

- induc inflamatie, activare limfocite

CELULE PREZENTATOARE DE ANTIGEN: celule dendritice, macrofage, limfocite B

- specializate in captarea, concentrarea, si prezentarea antigenelor pentrurecunoasterea de catre limfocite

LIMFOCITE

- mediatori ai raspunsului imun adaptativ (receptori specifici pentru antigen)

CELULE EFECTOARE: limfocite, granulocite, macrofage

- functia de eliminare a microbilor

CELULELE SISTEMULUI IMUN

Bariere anatomice

Factori:- fizici/mecanici- chimici- biologici

Raspuns umoral

IMUNITATE INNASCUTA IMUNITATE DOBINDITA

Raspunsinflamator

Fagocitoza

Activare Complement

Raspuns celular

Raspunsul imun in infectii bacteriene

Fagocitoza

Activare complement

Raspuns inflamator

Raspuns umoral (predominant)

Raspuns celular (in masura mai mica)

IMUNITATE INNASCUTA IMUNITATE DOBINDITA

Raspunsul imun in infectii cu bacterii extracelulare

Citotoxicitate celule NK

Secretie IFN gamma

Raspuns celular

– Ly T citotoxice: liza bacterii

– Ly Th1 secretie citokine (activare

macrofage)

IMUNITATE INNASCUTA IMUNITATE DOBINDITA

Raspunsul imun in infectii cu bacterii intracelulare

Imunitate innascuta Raspuns umoral

RECUNOASTERE IMUNA MECANISME EFECTOARE

Imunitate dobindita Raspuns celular

Cum raspunde sistemul imun la o varietate de agenti patogeni?

adaptate fiecarui tip de agent patogeninitiere & orientare

Protectie la re-infectare

MEMORIA IMUNOLOGICA

VACCINAREACel mai mare succes al politicilor de sanatatepublica

preluat din http://hugmeimvaccinated.org/

INFORMATII VACCINARE: http://www.cdc.gov/vaccines/default.htm