innate immunity

الرحمن اللة الرحمن بسم اللة بسمالرحيمالرحيم

Innate ImmunityInnate Immunity

PRESENTER

Shakira Ghazanfar

PhD [email protected]

الرحمن اللة الرحمن بسم اللة بسمالرحيمالرحيم

Innate ImmunityInnate Immunity

Defensive mechanisms include :Defensive mechanisms include : 1) Innate immunity 1) Innate immunity (Natural or Non specific) (Natural or Non specific)

2) Acquired immunity 2) Acquired immunity (Adaptive or Specific(Adaptive or Specific))

Cell-mediated immunity Humoral Cell-mediated immunity Humoral immunityimmunity

Component of Innate ImmunityComponent of Innate Immunity

Innate Immune systemInnate Immune system

First line First line Second lineSecond line

1) Mechanical barriers A- cells1) Mechanical barriers A- cells 2) Chemical & biochemical inhibitors 1- Natural killer2) Chemical & biochemical inhibitors 1- Natural killer

3) Normal flora 2- Phagocytes3) Normal flora 2- Phagocytes

B- Soluble factorsB- Soluble factors C- Inflammatory barriersC- Inflammatory barriers

First lineFirst line1) Mechanical barriers1) Mechanical barriers

- Intact skin - Intact skin

- Mucous coat- Mucous coat

- Mucous secretion- Mucous secretion

- Blinking reflex and tears- Blinking reflex and tears

- The hair at the nares- The hair at the nares

- Coughing and sneezing reflex- Coughing and sneezing reflex

First lineFirst line2) Chemical & biochemical inhibitors2) Chemical & biochemical inhibitors

- Sweet and sebaceous secretion- Sweet and sebaceous secretion

- Hydrolytic enzymes in saliva - Hydrolytic enzymes in saliva

- HCl of the stomach- HCl of the stomach

- Proteolytic enzyme in small intestine - Proteolytic enzyme in small intestine

- Lysozyme in tears- Lysozyme in tears

- Acidic pH in the adult vagina- Acidic pH in the adult vagina

First lineFirst line3) Normal bacterial flora3) Normal bacterial flora

- Competition for essential nutrients- Competition for essential nutrients

- Production of inhibitory - Production of inhibitory substancessubstances

Second lineSecond line A) cellsA) cells1- Natural killer (NK)1- Natural killer (NK)Definition:Definition: Large granular lymphocytesLarge granular lymphocytes Innate cytotoxic lymphocytesInnate cytotoxic lymphocytes

Source Source : : Bon marrow precursorsBon marrow precursors

LocationLocation :: 10% or 15% of lymphocytes in 10% or 15% of lymphocytes in peripheral bloodperipheral blood 1% or 2% of lymphocytes in 1% or 2% of lymphocytes in spleenspleen

Tumor cellsTumor cells

FunctionFunction :: Cytotoxic for Viral infected cells Cytotoxic for Viral infected cells Bacterial, fungal, parasitic infectionBacterial, fungal, parasitic infection

Responsible for antibody–dependent cellResponsible for antibody–dependent cell mediated cytotoxicity (mediated cytotoxicity (ADCC)ADCC)

Second lineSecond line2- Phagocytes2- Phagocytes

Specialized cells for capture, Ingestion and destruction of Specialized cells for capture, Ingestion and destruction of invading microorganismsinvading microorganisms

* Polymorphoniclear leucocytes, mainly * Polymorphoniclear leucocytes, mainly neutrophils:neutrophils: granulocytes circulate in blood granulocytes circulate in blood

** Mononuclear cells ( Mononuclear cells (macrophages)macrophages)

- - Monocytes Monocytes in bloodin blood

- Histocytes- Histocytes in connective tissues in connective tissues

- - Fixed reticuloendothelial cellsFixed reticuloendothelial cells in liver spleen, in liver spleen, lymph lymph

nods, bon marrow nods, bon marrow

Second lineSecond lineB- Soluble factorsB- Soluble factors

1- Acute phase protein 1- Acute phase protein (Plasma protein, CRP=C (Plasma protein, CRP=C reactive protein, Fibrin.)reactive protein, Fibrin.)

2- Complement 2- Complement (proteins in serum, body (proteins in serum, body fluids)fluids)

2- Interferons 2- Interferons (Proteins against viral (Proteins against viral infections)infections)

3- Properdin 3- Properdin (Complement activation)(Complement activation)

4- Beta lysine 4- Beta lysine (Antibacterial protein from (Antibacterial protein from Platelets)Platelets)

5- Lactoferrrin,Transferrin 5- Lactoferrrin,Transferrin (Iron binding protein)(Iron binding protein)

6- Lactoperoxidase 6- Lactoperoxidase (Saliva & Milk)(Saliva & Milk)

7- Lysozyme 7- Lysozyme (Hydrolyze cell wall)(Hydrolyze cell wall)

InterferonsInterferons

Proteins usually produced by virally infected cellsProteins usually produced by virally infected cells

* Types of interferons:* Types of interferons:

1- Alpha interferon 1- Alpha interferon Secreted by MacrophagesSecreted by Macrophages Induced by Viruses or PolynucleotideInduced by Viruses or Polynucleotide

2- Beta interferon 2- Beta interferon Secreted by Fibroblasts, VirusesSecreted by Fibroblasts, Viruses

3- Gamma interferon 3- Gamma interferon T- lymphocytes, Specific antigensT- lymphocytes, Specific antigens

InterferonsInterferons

Protective action of interferons:Protective action of interferons:

1) Activate T-cells1) Activate T-cells

2) Activate macrophages2) Activate macrophages

3) Activate NK3) Activate NK

PhagocytosisPhagocytosis

The engulfment, digestion, and subsequent processingThe engulfment, digestion, and subsequent processing

of microorganisms by macrophages and neutrophilsof microorganisms by macrophages and neutrophils

1) Chemotaxis & attachment:1) Chemotaxis & attachment:

a- Attraction by chemotactic substances a- Attraction by chemotactic substances

(microbes, damaged tissues)(microbes, damaged tissues)

b- Attachment by receptors on surfaces b- Attachment by receptors on surfaces

of phagocytes of phagocytes


2) Ingestion:2) Ingestion:

* Phagocyte pseudopodia surround * Phagocyte pseudopodia surround organism forming phagosomorganism forming phagosom

* Opsinins and co-factors enhance * Opsinins and co-factors enhance phagocytosisphagocytosis

* Fusion with phagocyte granules and * Fusion with phagocyte granules and release release

digestive, toxic contentsdigestive, toxic contents


3- Killing (two microbicidal routes)3- Killing (two microbicidal routes) a- Oxygen depended system (powerful microbicidal a- Oxygen depended system (powerful microbicidal

agents)agents) Oxygen converted to superoxide, anion, Oxygen converted to superoxide, anion, hydrogen peroxide, activated oxygen and hydrogen peroxide, activated oxygen and hydroxyl radicals.hydroxyl radicals. b- Oxygen-independent system (anaerobic b- Oxygen-independent system (anaerobic conditions)conditions) Digestion and killing by lysozyme. Lactoferrin, Digestion and killing by lysozyme. Lactoferrin, low pH, cationic proteins and hydrolytic and low pH, cationic proteins and hydrolytic and proteolytic enzymesproteolytic enzymes

C) Inflammatory BarriersC) Inflammatory Barriers

* Tissue damage by a wound or by invading pathogen* Tissue damage by a wound or by invading pathogen

* Inflammatory response:* Inflammatory response: Tissue damageTissue damageRelease of chemical mediators fromRelease of chemical mediators from Leukocytes Leukocytes (Histamine, fibrin, kinins, cytokines)(Histamine, fibrin, kinins, cytokines) Invading microbe Invading microbe Redness of tissueRedness of tissue Tissue temperature Tissue temperature Vasodilatation of capillariesVasodilatation of capillaries Capillary permeability Capillary permeability Influx of fluidsInflux of fluids Influx of phagocytes Influx of phagocytes into tissuesinto tissues

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innate immunity

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