1. immunity

IMMUNOLOGYIMMUNOLOGYAruni Puthuppally

Asst ProfessorNoorul Islam Dental College

Trivandrum

ImmunologyImmunology

The group of cells, tissues and molecules that are The group of cells, tissues and molecules that are

associated with the resistance to microbial associated with the resistance to microbial

invasion is called invasion is called immune systemimmune system..

The coordinated reaction of immune system The coordinated reaction of immune system

towards the microbes is known as towards the microbes is known as immune immune

responseresponse..

The immune system is made up mainly of The immune system is made up mainly of

lymphoid organslymphoid organs and and reticuloendothelial cells.reticuloendothelial cells.

The RE cells consisting of The RE cells consisting of lymphocyteslymphocytes and and

plasma cellsplasma cells are the key mediators of the immune are the key mediators of the immune

response.response.

MALT

The Organs of the Immune SystemThe Organs of the Immune System

The Cells of the Immune SystemThe Cells of the Immune System

Lymphocytes originated from thymus are known Lymphocytes originated from thymus are known

as T-lymphocytes and are responsible for as T-lymphocytes and are responsible for Cell Cell

Mediated Immunity (CMI).Mediated Immunity (CMI).

Lymphocytes originated from bone marrow are Lymphocytes originated from bone marrow are

known as B-lymphocytes and are responsible for known as B-lymphocytes and are responsible for

Antibody Mediated or Humoral Immunity (AMI).Antibody Mediated or Humoral Immunity (AMI).

AMIAMI

CMICMI

Antibody Mediated ImmunityAntibody Mediated Immunity

Antibody mediated immunity (AMI) provides primary Antibody mediated immunity (AMI) provides primary defense against most extracellular bacterial pathogens and defense against most extracellular bacterial pathogens and their toxins.their toxins.

Abs are present in blood, lymph and mucus secretions.Abs are present in blood, lymph and mucus secretions.

B cells are responsible for the production of Abs.B cells are responsible for the production of Abs.

AMI helps in defense against viruses that infect through the AMI helps in defense against viruses that infect through the RT and GIT.RT and GIT.

It participate in the pathogenesis of immediate type 1,2 and 3 It participate in the pathogenesis of immediate type 1,2 and 3 HS and certain autoimmune diseases.HS and certain autoimmune diseases.

Cell Mediated ImmunityCell Mediated Immunity

CMI protects against infection by fungi, viruses CMI protects against infection by fungi, viruses and facultative intracellular bacterial pathogens.and facultative intracellular bacterial pathogens.

CMI participate in the rejection of homograft and CMI participate in the rejection of homograft and GVH reaction.GVH reaction.

It provides immunological surveillance and It provides immunological surveillance and immunity against cancer.immunity against cancer.

CMI mediates the pathogenesis of delayed type 4 CMI mediates the pathogenesis of delayed type 4 HS and certain autoimmune diseases.HS and certain autoimmune diseases.

ImmunityImmunityImmunityImmunity Host resistance against microorganisms & other substances.Host resistance against microorganisms & other substances. Host resistance against microorganisms & other substances.Host resistance against microorganisms & other substances.

Immune responseImmune response : Rx : Rxn n of the body against of the body against

foreign antigen.foreign antigen.

Immune responseImmune response : Rx : Rxn n of the body against of the body against

foreign antigen.foreign antigen.

ImmunityImmunity

InnateInnate AcquiredAcquired

Innate ImmunityInnate ImmunityInnate ImmunityInnate Immunity

Inborn resistance present Inborn resistance present

Genetic and constitutional make upGenetic and constitutional make up

Does not require prior exposureDoes not require prior exposure

Not modified significantly by repeated exposureNot modified significantly by repeated exposure

Inborn resistance present Inborn resistance present

Genetic and constitutional make upGenetic and constitutional make up

Does not require prior exposureDoes not require prior exposure

Not modified significantly by repeated exposureNot modified significantly by repeated exposure

Innate ImmunityInnate Immunity

IndividualIndividualSpeciesSpecies RacialRacial

Plant VirusPlant VirusPlant VirusPlant Virus

Physiological and Biochemical Physiological and Biochemical DifferencesDifferences

Physiological and Biochemical Physiological and Biochemical DifferencesDifferences

XX

Innate ImmunityInnate Immunity

IndividualIndividualSpeciesSpecies RacialRacial

XX

More More susceptible susceptible

for for TBTB

More More susceptible susceptible

for for TBTB

Algerian Algerian sheepsheep

Innate ImmunityInnate Immunity

IndividualIndividualSpeciesSpecies RacialRacial

Show similar sensitivity or resistanceShow similar sensitivity or resistanceShow similar sensitivity or resistanceShow similar sensitivity or resistance

Do not show such similarityDo not show such similarityDo not show such similarityDo not show such similarity

Factors influencing level of immunity

Factors influencing level of immunity

Two

Extremes

Factors influencing level of immunity

Factors influencing level of immunity

Factors influencing level of immunity

Factors influencing level of immunity

Components of Innate ImmunityComponents of Innate ImmunityComponents of Innate ImmunityComponents of Innate Immunity

Physical Physical barriersbarriersPhysical Physical barriersbarriers

Chemical Chemical barriersbarriers

Chemical Chemical barriersbarriers

Biological Biological barriersbarriers

Biological Biological barriersbarriers

Physical BarriersPhysical Barriers

11. Skin and Mucous Membranes. Skin and Mucous Membranes

Form a ‘wall’ between deep tissues and Form a ‘wall’ between deep tissues and pathogens.pathogens.

22. “Flushing” mechanisms. “Flushing” mechanisms

a.a. Salivary flow Salivary flow Prevents bacterial Prevents bacterial overgrowthovergrowth

b.b. Coughing & Sneezing Coughing & Sneezing Clears Clears respiratory tractrespiratory tract

c.c. Urination Urination Flushes the urinary Flushes the urinary tracttract

d.d. Lacrimation Lacrimation Cleanses eyesCleanses eyes

e.e. Ciliary action Ciliary action Expels bacteriaExpels bacteria

Physical BarriersPhysical Barriers

11. Skin and Mucous Membranes. Skin and Mucous Membranes

Form a ‘wall’ between deep tissues and Form a ‘wall’ between deep tissues and pathogens.pathogens.

22. “Flushing” mechanisms. “Flushing” mechanisms

a.a. Salivary flow Salivary flow Prevents bacterial Prevents bacterial overgrowthovergrowth

b.b. Coughing & Sneezing Coughing & Sneezing Clears Clears respiratory tractrespiratory tract

c.c. Urination Urination Flushes the urinary Flushes the urinary tracttract

d.d. Lacrimation Lacrimation Cleanses eyesCleanses eyes

e.e. Ciliary action Ciliary action Expels bacteriaExpels bacteria

Chemical BarriersChemical Barriers

1. pH of body fluids1. pH of body fluids Inhibits growth of Inhibits growth of

many pathogensmany pathogens

2. Lysozyme2. Lysozyme Breaks down cell walls of Breaks down cell walls of

bacteriabacteria

3. Interferon3. Interferon Inhibits viral replication Inhibits viral replication

Chemical BarriersChemical Barriers

1. pH of body fluids1. pH of body fluids Inhibits growth of Inhibits growth of

many pathogensmany pathogens

2. Lysozyme2. Lysozyme Breaks down cell walls of Breaks down cell walls of

bacteriabacteria

3. Interferon3. Interferon Inhibits viral replication Inhibits viral replication

Biological BarriersBiological Barriers

1. Natural resistance1. Natural resistance Species Species

resistance to microbesresistance to microbes

2. Normal flora2. Normal flora Competes with Competes with

invadersinvaders

3. Inflammation3. Inflammation Localizes & destroys Localizes & destroys

pathogenspathogens

4. Complement4. Complement Cell lysis and Cell lysis and

phagocytosisphagocytosis

5. Phagocytosis5. Phagocytosis Engulfment of Engulfment of

pathogenspathogens

Biological BarriersBiological Barriers

1. Natural resistance1. Natural resistance Species Species

resistance to microbesresistance to microbes

2. Normal flora2. Normal flora Competes with Competes with

invadersinvaders

3. Inflammation3. Inflammation Localizes & destroys Localizes & destroys

pathogenspathogens

4. Complement4. Complement Cell lysis and Cell lysis and

phagocytosisphagocytosis

5. Phagocytosis5. Phagocytosis Engulfment of Engulfment of

pathogenspathogens

Mechanisms of Innate Mechanisms of Innate ImmunityImmunity

Mechanisms of Innate Mechanisms of Innate ImmunityImmunity

A.A. Non immunological defensesNon immunological defenses

B.B. Immunological defensesImmunological defenses

A.A. Non immunological defensesNon immunological defenses

B.B. Immunological defensesImmunological defenses

AA

• Epithelial surfaceEpithelial surface

• Microbial antagonismMicrobial antagonism

BB

• Antibacterial agents in blood & tissuesAntibacterial agents in blood & tissues

• Cellular factorsCellular factors

• FeverFever

• Acute phase proteinsAcute phase proteins

• InflammationInflammation

Immunologic DefensesImmunologic DefensesImmunologic DefensesImmunologic Defenses

Antibody mediatedAntibody mediated - - IgM, IgG, IgAIgM, IgG, IgA

Cell mediatedCell mediated - T lymphocytes- T lymphocytes

PhagocytosisPhagocytosis - Neutrophils, Macrophages- Neutrophils, Macrophages

ComplementComplement - Lysis & enhances - Lysis & enhances

phagocytosisphagocytosis

Antibody mediatedAntibody mediated - - IgM, IgG, IgAIgM, IgG, IgA

Cell mediatedCell mediated - T lymphocytes- T lymphocytes

PhagocytosisPhagocytosis - Neutrophils, Macrophages- Neutrophils, Macrophages

ComplementComplement - Lysis & enhances - Lysis & enhances

phagocytosisphagocytosis

Acute Phase ProteinsAcute Phase ProteinsAcute Phase ProteinsAcute Phase Proteins

Activate alternate pathway of Activate alternate pathway of

complementcomplement

•C reactive proteinC reactive protein

•Mannose binding proteinMannose binding protein

•Alpha – 1- acid glycoproteinAlpha – 1- acid glycoprotein

•Amyloid PAmyloid P

Activate alternate pathway of Activate alternate pathway of

complementcomplement

•C reactive proteinC reactive protein

•Mannose binding proteinMannose binding protein

•Alpha – 1- acid glycoproteinAlpha – 1- acid glycoprotein

•Amyloid PAmyloid P

FeverFever

A rise in temperature following infection A rise in temperature following infection

is a natural defense mechanism.is a natural defense mechanism.

Pathogens like Pathogens like Treponema pallidumTreponema pallidum will will

be destructed at high temperature.be destructed at high temperature.

It stimulate the production of interferon It stimulate the production of interferon

and aids recovery from viral infections.and aids recovery from viral infections.

OpsonizationOpsonization – a process that facilitates – a process that facilitates

phagocytosis by coating antigens with phagocytosis by coating antigens with

opsonin (Eg. antibody and C3b)opsonin (Eg. antibody and C3b)

OpsonizationOpsonization – a process that facilitates – a process that facilitates

phagocytosis by coating antigens with phagocytosis by coating antigens with

opsonin (Eg. antibody and C3b)opsonin (Eg. antibody and C3b)

InflammationInflammationInflammationInflammation

Immunological response to tissue injury.Immunological response to tissue injury.

Non-specific defense mechanism.Non-specific defense mechanism.

Vascular changes & recruitment of neutrophils & Vascular changes & recruitment of neutrophils &

macrophages.macrophages.

Immunological response to tissue injury.Immunological response to tissue injury.

Non-specific defense mechanism.Non-specific defense mechanism.

Vascular changes & recruitment of neutrophils & Vascular changes & recruitment of neutrophils &

macrophages.macrophages.

Classic features of InflammationClassic features of Inflammation

1. Calor (Heat)

2. Dolor (Pain)

3. Rubor (Redness)

4. Tumor (Swelling)

Classic features of InflammationClassic features of Inflammation

1. Calor (Heat)

2. Dolor (Pain)

3. Rubor (Redness)

4. Tumor (Swelling)

Cells & Proteins in Inflammatory Reactions Cells & Proteins in Inflammatory Reactions

Cells Cells

•PhagocytesPhagocytes

•Monocyte-Monocyte-

Macrophage Macrophage

•Natural killer cellNatural killer cell

Cells Cells

•PhagocytesPhagocytes

•Monocyte-Monocyte-

Macrophage Macrophage

•Natural killer cellNatural killer cell

Specific proteinsSpecific proteins

•CRPCRP

•Mannose binding Mannose binding

proteinprotein

•Amyloid proteinAmyloid protein

•Prostaglandins Prostaglandins

Specific proteinsSpecific proteins

•CRPCRP

•Mannose binding Mannose binding

proteinprotein

•Amyloid proteinAmyloid protein

•Prostaglandins Prostaglandins

Cytokines:Cytokines:

Biologically active proteins that are released Biologically active proteins that are released

during inflammationduring inflammation

During inflammation, they:During inflammation, they:

1) Affect the local microcirculation by 1) Affect the local microcirculation by

causing vasodilation causing vasodilation and increased and increased

vascular permeability vascular permeability

2) Attract immune system cells to the site 2) Attract immune system cells to the site

and activate cells and activate cells involved in tissue repair. involved in tissue repair.

Cytokines:Cytokines:

Biologically active proteins that are released Biologically active proteins that are released

during inflammationduring inflammation

During inflammation, they:During inflammation, they:

1) Affect the local microcirculation by 1) Affect the local microcirculation by

causing vasodilation causing vasodilation and increased and increased

vascular permeability vascular permeability

2) Attract immune system cells to the site 2) Attract immune system cells to the site

and activate cells and activate cells involved in tissue repair. involved in tissue repair.

Diapedesis – movement of blood cells between endothelial cells

lining blood vessels

Chemotaxis – migration of cells in response to concentration gradients

of certain factors

Chemotaxis – migration of cells in response to concentration gradients

of certain factors

Neutrophil Extravasation In Inflammation

Blood flow

Innate Immunity

ImmunityImmunity

InnateInnate AcquiredAcquired

Acquired ImmunityAcquired ImmunityAcquired ImmunityAcquired Immunity

The resistance that an individual acquires during life.The resistance that an individual acquires during life.

es dramatically with subsequent exposure to the es dramatically with subsequent exposure to the

same Ag.same Ag.

Immune response primarily refers to acquired Immune response primarily refers to acquired

immunity.immunity.

The resistance that an individual acquires during life.The resistance that an individual acquires during life.

es dramatically with subsequent exposure to the es dramatically with subsequent exposure to the

same Ag.same Ag.

Immune response primarily refers to acquired Immune response primarily refers to acquired

immunity.immunity.

Lymphocytes (B,T)Lymphocytes (B,T)Lymphocytes (B,T)Lymphocytes (B,T)Phagocytes, Phagocytes, NK cellsNK cells

Phagocytes, Phagocytes, NK cellsNK cells

CellsCellsCellsCells

YesYesYesYesNo No No No Immunological Immunological memorymemory

Immunological Immunological memorymemory

YesYesYesYes NoNo NoNoImproved Improved response response

upon re - exposureupon re - exposure

Improved Improved response response

upon re - exposureupon re - exposure

SpecificSpecificSpecificSpecificGeneralGeneralGeneralGeneralSpecificitySpecificitySpecificitySpecificity

““Second”Second”““Second”Second”““First”First”““First”First”““Line of defense”Line of defense”““Line of defense”Line of defense”

AcquiredAcquired ImmunityImmunityAcquiredAcquired ImmunityImmunity

Innate Innate ImmunityImmunity

Innate Innate ImmunityImmunity

Comparison

Comparison

Comparison

Comparison

AcquiredAcquiredImmunityImmunity

NaturalNatural ArtificialArtificial NaturalNatural ArtificialArtificial

ActiveActive PassivePassive

ActiveActive – Resistance developed as a result of antigenic stimulus – Resistance developed as a result of antigenic stimulus

Passive Passive – Resistance that is transmitted in a readymade form – Resistance that is transmitted in a readymade form

ActiveActive – Resistance developed as a result of antigenic stimulus – Resistance developed as a result of antigenic stimulus

Passive Passive – Resistance that is transmitted in a readymade form – Resistance that is transmitted in a readymade form

Types of Acquired immunityTypes of Acquired immunityTypes of Acquired immunityTypes of Acquired immunity

Induction of immunity by infection or with a Induction of immunity by infection or with a

vaccine is called vaccine is called Active Immunity.Active Immunity. NaturalNatural : By a clinical or inapparent : By a clinical or inapparent

infection.infection. ArtificialArtificial : By vaccines. : By vaccines.

Induction of immunity by infection or with a Induction of immunity by infection or with a

vaccine is called vaccine is called Active Immunity.Active Immunity. NaturalNatural : By a clinical or inapparent : By a clinical or inapparent

infection.infection. ArtificialArtificial : By vaccines. : By vaccines.

Active ImmunityActive ImmunityActive ImmunityActive Immunity

The resistance that is transmitted to a recipient in The resistance that is transmitted to a recipient in a readymade form.a readymade form.

Here the recipient’s immune system plays no Here the recipient’s immune system plays no active role.active role.

There is no latent period, but immunity is There is no latent period, but immunity is transient.transient.

Non-immune individual can be made immune by Non-immune individual can be made immune by transferring serum or lymphocytes from an transferring serum or lymphocytes from an immune individual.immune individual.

Serum constituents (antibodies) and lymphocytes Serum constituents (antibodies) and lymphocytes are involved in immunity.are involved in immunity.

The resistance that is transmitted to a recipient in The resistance that is transmitted to a recipient in a readymade form.a readymade form.

Here the recipient’s immune system plays no Here the recipient’s immune system plays no active role.active role.

There is no latent period, but immunity is There is no latent period, but immunity is transient.transient.

Non-immune individual can be made immune by Non-immune individual can be made immune by transferring serum or lymphocytes from an transferring serum or lymphocytes from an immune individual.immune individual.

Serum constituents (antibodies) and lymphocytes Serum constituents (antibodies) and lymphocytes are involved in immunity.are involved in immunity.

Passive ImmunityPassive ImmunityPassive ImmunityPassive Immunity

Passive ImmunityPassive ImmunityPassive ImmunityPassive Immunity

Natural Natural : Mother to fetus.: Mother to fetus.

Artificial Artificial : Administration of antibodies. Ex: ATS, TIG: Administration of antibodies. Ex: ATS, TIG

Uses of passive immunityUses of passive immunity : :

•Temporary protection of non-immunised patientsTemporary protection of non-immunised patients

•For treatment of particular infectionFor treatment of particular infection

•For suppression of active immunity, Eg: RhIgFor suppression of active immunity, Eg: RhIg

Natural Natural : Mother to fetus.: Mother to fetus.

Artificial Artificial : Administration of antibodies. Ex: ATS, TIG: Administration of antibodies. Ex: ATS, TIG

Uses of passive immunityUses of passive immunity : :

•Temporary protection of non-immunised patientsTemporary protection of non-immunised patients

•For treatment of particular infectionFor treatment of particular infection

•For suppression of active immunity, Eg: RhIgFor suppression of active immunity, Eg: RhIg

Comparison of active & Passive Comparison of active & Passive immunityimmunity

Comparison of active & Passive Comparison of active & Passive immunityimmunity

Applicable in immunodeficientApplicable in immunodeficientApplicable in immunodeficientApplicable in immunodeficientNot applicable in the Not applicable in the immunodeficient immunodeficient

Not applicable in the Not applicable in the immunodeficient immunodeficient

No negative phaseNo negative phaseNo negative phaseNo negative phase‘‘Negative phase’ may occurNegative phase’ may occur‘‘Negative phase’ may occurNegative phase’ may occur

Subsequent dose less effectiveSubsequent dose less effectiveSubsequent dose less effectiveSubsequent dose less effectiveBooster effect on subsequent Booster effect on subsequent dosedose

Booster effect on subsequent Booster effect on subsequent dosedose

No memoryNo memoryNo memoryNo memoryImmunological memory present Immunological memory present

Immunological memory present Immunological memory present

Immediate immunityImmediate immunityImmediate immunityImmediate immunityImmunity effective only after lag Immunity effective only after lag periodperiod

Immunity effective only after lag Immunity effective only after lag periodperiod

Transient, less effectiveTransient, less effectiveTransient, less effectiveTransient, less effectiveDurable, effective protectionDurable, effective protectionDurable, effective protectionDurable, effective protection

Readymade antibody transferredReadymade antibody transferredReadymade antibody transferredReadymade antibody transferredInduced by infection or by Induced by infection or by immunogensimmunogens

Induced by infection or by Induced by infection or by immunogensimmunogens

Received passively,No active Received passively,No active host participhost participnn

Received passively,No active Received passively,No active host participhost participnn

Produced actively by host’s Produced actively by host’s immune systemimmune system

Produced actively by host’s Produced actively by host’s immune systemimmune system

Passive ImmunityPassive ImmunityPassive ImmunityPassive ImmunityActive ImmunityActive ImmunityActive ImmunityActive Immunity

Adoptive immunityAdoptive immunityAdoptive immunityAdoptive immunity

Extract of immunologically competent Extract of immunologically competent

lymphocytes: Transfer factor, are injectedlymphocytes: Transfer factor, are injected

Application- Lepromatous leprosyApplication- Lepromatous leprosy

Extract of immunologically competent Extract of immunologically competent

lymphocytes: Transfer factor, are injectedlymphocytes: Transfer factor, are injected

Application- Lepromatous leprosyApplication- Lepromatous leprosy

Local immunityLocal immunityLocal immunityLocal immunity

Achieved by administration of live vaccinesAchieved by administration of live vaccines

•Eg: Polio vaccineEg: Polio vaccine

Secretory IgA produced locally by plasma Secretory IgA produced locally by plasma

cellscells

These IgA are responsible for thisThese IgA are responsible for this

Achieved by administration of live vaccinesAchieved by administration of live vaccines

•Eg: Polio vaccineEg: Polio vaccine

Secretory IgA produced locally by plasma Secretory IgA produced locally by plasma

cellscells

These IgA are responsible for thisThese IgA are responsible for this

Herd immunityHerd immunityHerd immunityHerd immunity

Refers to overall level of immunity in a communityRefers to overall level of immunity in a community

Relevant in controlling epidemic diseaseRelevant in controlling epidemic disease

Eradication of communicable diseases depends on Eradication of communicable diseases depends on

the development of a high level of herd immunitythe development of a high level of herd immunity

Refers to overall level of immunity in a communityRefers to overall level of immunity in a community

Relevant in controlling epidemic diseaseRelevant in controlling epidemic disease

Eradication of communicable diseases depends on Eradication of communicable diseases depends on

the development of a high level of herd immunitythe development of a high level of herd immunity

ImmunologImmunologyy

Your Skin

Pathogen

Pathogen

Your T-cell

Your WBC

Factors influencing level of Factors influencing level of immunityimmunity

Factors influencing level of Factors influencing level of immunityimmunity

Two

Extremes

Factors influencing level of immunity

Factors influencing level of immunity

Factors influencing level of immunity

Factors influencing level of immunity

Components of Innate Immunity

Physical Barriers Chemical Barriers Biological Barriers

Innate immunityInnate immunity

Acquired immunityAcquired immunity

Active immunity Active immunity

Passive immunityPassive immunity

Factors influencing innate immunityFactors influencing innate immunity

Comparison – active and passive Comparison – active and passive

immunityimmunity

Mechanism of innate immunityMechanism of innate immunity

Innate immunityInnate immunity

Acquired immunityAcquired immunity

Active immunity Active immunity

Passive immunityPassive immunity

Factors influencing innate immunityFactors influencing innate immunity

Comparison – active and passive Comparison – active and passive

immunityimmunity

Mechanism of innate immunityMechanism of innate immunity

Local immunityLocal immunity

Herd immunityHerd immunity

Adoptive immunityAdoptive immunity

VaccinesVaccines

Cell Mediated ImmunityCell Mediated Immunity

Antibody Mediated ImmunityAntibody Mediated Immunity

Local immunityLocal immunity

Herd immunityHerd immunity

Adoptive immunityAdoptive immunity

VaccinesVaccines

Cell Mediated ImmunityCell Mediated Immunity

Antibody Mediated ImmunityAntibody Mediated Immunity

In severe combined immunodeficiency, a person's ability to fight infections is severely impaired. This

condition has been dubbed "bubble boy disease" and became widely known during the 1970s with the case of David Vetter, who lived for 12 years

sealed in a plastic, germfree environment.

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