IMMUNE SYSTEM ORGANS CELLS I STEM OR MOTHER

IMMUNE SYSTEM ORGANS & CELLS

I – STEM OR MOTHER CELLS: It’s the place of the origin (Generation of lymphocytes) *found in the fetal liver during embryonal life. *then after birth → from bone marrow.

II- PRIMARY LYMPHOID ORGANS : (CENTRAL LYMPHOID ORGAN) Function … *maturation *education of the cellslymphocyte *differentiation Where the cells enter to grow, proliferate, mature, differentiate & transformed into the secondary lymphoid organ.

THESE ORGANS ARE … Thymus → for T-lymphocytes. Bursa equivalent (In mammals), bursa fabracius (In birds). Bursa equivalent (bone marrow) in mammals & payer patches in cattle.

THYMUS GLAND 1 ST It is bi-lobe gland present on both sides in the esophagus in the entrance of esophagus cavity. In birds →it is 14 lobes It found from birth & continue to increase in size to full size at puberty, then decrease in size. The thymus consist of cortex & medulla. There is thymus barrier between the blood and the T cell unable to react with antigen. T- lymphocyte → called T cell because it’s maturation occurin thymus.

IN THIS THYMUS: The T cell maturation. education (Carry receptor called CD 4 & CD 8) Differentiation. T cytotoxic & T suppressor → carry CD 8 T helper → carry CD 4

2 ND BURSA OF FABRICIUS Sac of lymphoid tissue present on cloaca present in birds. Responsible for maturation, education & differentiation of B-lymphocytes

3 RD BURSA EQUIVALENT Group of tissues differ from mammals to another. In human, rodents → bone marrow. In cattle → payers patches

III-SECONDARY LYMPHOID ORGANS: (PERIPHERAL I. O). . Spleen, lymph nodes, tonsils, lymphoid organ (MALT). MALT→ mucosal associated lymphoid tissue. 1. 2. Spleen: Consist of white pulb & red pulb. For B cell in perarteriolosheath For T-Cell in white follicle. Lymph node: It is consist of : cortex → housing of B-cell Paracortical area → housing T-Cell. Medulla → for another immune cells. 3. 4. Tonsils Malt Aggregates of lymphoid organ. e. g. BALT → baronchial associated lymphatic tissue. MALT → mucosal associated lymphatic tissue. GALT → gut associated lymphatic tissue.

Other name Function Size Removal Reaction to antigen 1 ry lymphoid 2 ry lymphoid Central L. T Peripheral L. T Maturation, education, differentiation Increase to size ↑ in to full size puberty After the immunity Can’t react with Ag The small size on life Not affect the puberty React with Antigen

CELL OF IMMUNE SYSTEM 1 - Lymphocytes Origin Maturation education Storage B cells T cells B. M, liver of fetus B. M. , liver of fetus Bursa of fabricius Thymus bursa equivalent (B. M. , players patches) Spleen, (Periaertiolar tonsils, cortex) lymph node, MALT. Spleen (white follicle), tonsils (Paracortical area) L. node, MALT

CONTINUE…. Types Cells products (Secretions) One 1 type Th→ T helper, help both humeral and cell mediated immunity (Carry CD 4) Tc → T cytotoxic Ts → T suppress of immune system after complete Ag destructiare. Bcel differentiate to Active Tc release certain plasma cell & memory enzymes called lymphokine. cells. Plasma cell: secret Antibody

CONTINUE…. Lymphocytes transformation Life spane 1. For Ag 2. E-rosette formation (receptor to sheep RBC) 3. C 3 b for complement 4. Carry MHC 5. Other receptor Yes to plasma cell Short Receptor BCR No Yes to small lymphocytes Long Yes MHCI &MHCII because it is Apc CD 19, CD 21 No MHCI TCR Yes CD 3 Th → CD 4 Tc & Ts → CD 8 CD 2 & CD 58

CELLS THAT LINK IN INNATE & ADAPTIVE IMMUNITY (APC). . Antigen Presenting Cells: A) Dendritic cell: It is cell found in epithelial tissue. It is APC & act also as phagocytic cell as m. ø. What is APC doing? APC → Carry to Ag on MHCII, this antigen is exogenous Ag- & present it to Th. T helper carry CD 4 for MHCII or carry Ag direct to B cells. N B APC → carry the antigen after engulfment, fragmentation to different epitopes. Then epitope exposed on surfaces of APC with MHCII.

B) Macrophage: as (A) C) B cells: Act as APC in the 2 ry immune response Can be activated directly by exogenous antigen but fully activated by T-helper cell which secret factors → help B-cell to be fully activated.

RECEPTORS OR MARKERS OF T & B CELL 1) Ag binding receptors → BCR, TCR BCR (B cell receptor) TCR (T cell receptor) 2 polypeptide (α, β) 2 class of 100, 000 copy immunoglobulin (Ig. M Is less and Ig. D) Not specified There are 200, 000500, 000 Bivalent Specified

2) OTHER RECEPTOR ON T CELL CD 2 & CD 58 → Bind m. ø. CD 3 → To amplify signals. CD 4 on Th → for MHCII. CD 8 on Tc & Ts → for MHCI.

3) MAJOR HISTO-COMPATIBILITY COMPLEX Group of surface receptor. MHCI: On an nucleated cells, carry endogenous antigenous for T cytotoxic & T suppressor. MHCII: on APC (m. ø. B cells & dendritic cells) Carry exogenous Ag. To T helper and B cells

4) RECEPTOR FOR REGULATOR THE FUNCTION OF T & B CELLS For complement For cytokine For antibody 5) RECEPTOR FOR UNKNOWN FUNCTION.

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