CELLS & ORGANS OF IMMUNE SYSTEM

ADAPTIVE  IMMUNITY

1.GRANULOCYTIC CELLS-

                -Neutrophils

                -Eosinophils

                -Basophils

2-MONONUCLEAR PHAGOCYTES

                Enter from bone marrow as MONOCYTES and migrate to tissue as

                -Microglial cells of CNS

                -Kupffer cells of liver and vascular lining

                -Alveolar macrophages of Lung

3-DENDRITIC CELLS-

                In skin,gut mucosa, alveoli

4-LYMPHOCYSTES

                A-B LYMPHOCYTES-From Bone marrow-Produce antibody as mature plasma cells

                B-T LYMPHOCYTES-Develop in Thymus

                                1-T helper cell with CD4

                                2-CTL-Cytotoxic T lymphocytes with CD8

5-NATURAL KILLER CELLS-Large granular lymphocytes bearing CD16 and CD56-

BONE MARROW,THYMUS,LYMPH NODES,SPLEEN and various Mucosa associated Lymph tissue are associated with development of immune responce.

All cells develop in bone marrow except for follicular dendritic cells.

INNATE IMMUNE RESPONSES

Lack Antigen specificity and same set of diffence mechanism for all pathogens.

Earliest barriers to pathogens entry are physical and chemical as cilliary action of bronchial mucosa, enzymes in saliva and sweat, acidity of stomach

PAMP-Pathogen associated Molecular pattern

PRRs- PATTERN recognition Receptors-most important is TLR

                                                                                -NOD-1, NOD-2

When activated lead to production of proinflamatory cytokines ,antiviral cytokines,interferon alfa,

COMPLEMENT SYSTEM

20 SERUM PROTEINS WHICH AMPLIFIES the immune response and a single molecule can trigger thousands of terminal effector molecules.

3 pathways

1-Classical pathway-activated by antigen-antibody complex

2-alternate pathway-activated by polysaccharides of yeasts and gram negative bacteria

3-Mannon binding lecithin pathway-activated by mannose containg protein of bacteria

All pathway activation culminates in activation of C3 and generation of C5-C9 complexes(Membrane attack complex or MAC)

FUNCTION-

1-Lysis of invading bacteria

2-Opsonisation of organisms

3-Clearence of antigen-antibody complex

4-Trigegring specific cell function