1. Immune system organs & cells

2. 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.

3. 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.

4. 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.

5. THYMUS GLAND 1st
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.

6. In this thymus: The T cell maturation.
education (Carry receptor called CD4 & CD8)
Differentiation.
T cytotoxic & T suppressor → carry CD8 
T helper → carry CD4

7. 2nd bursa of fabricius
Sac of lymphoid tissue present on cloaca present in birds.
Responsible for maturation, education & differentiation of B-lymphocytes

8. 3rd bursa equivalent Group of tissues differ from mammals to another.
In human, rodents → bone marrow.
In cattle → payers patches

9. III-Secondary lymphoid organs:(Peripheral I.O)..
Spleen, lymph nodes, tonsils, lymphoid organ (MALT).
MALT→ mucosal associated lymphoid tissue.
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.
Tonsils
Malt
Aggregates of lymphoid organ. e.g. BALT → baronchial associated lymphatic tissue.
MALT → mucosal associated lymphatic tissue.
GALT → gut associated lymphatic tissue.

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

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

12. Continue…. Types One 1 type
Th→ T helper, help both humeral and cell mediated immunity (Carry CD4)
Tc → T cytotoxic
Ts → T suppress of immune system after complete Ag destructiare.
Cells products (Secretions)
Bcel differentiate to plasma cell & memory cells.
Plasma cell: secret Antibody
Active Tc release certain enzymes called lymphokine.

13. Continue…. Lymphocytes transformation Yes to plasma cell
Yes to small lymphocytes
Life spane
Short
Long
Receptor
For Ag
BCR
TCR
2. E-rosette formation (receptor to sheep RBC) No
Yes
3. C3b for complement
4. Carry MHC
MHCI &MHCII because it is Apc
MHCI
5. Other receptor
CD19, CD21
CD3
Th → CD4
Tc & Ts → CD8
CD2 & CD 58

14. 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 CD4 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.

15. B) Macrophage: as (A)
C) B cells:
Act as APC in the 2ry 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.

16. Receptors or Markers of T & B cell
1) Ag binding receptors → BCR, TCR
BCR (B cell receptor)
2 class of immunoglobulin (IgM and IgD)
There are 200, ,000
Bivalent
Specified
TCR (T cell receptor)
2 polypeptide (α, β)
100,000 copy
Is less
Not specified

17. 2) Other receptor on T cell
CD2 & CD58 → Bind m.ø.
CD3 → To amplify signals.
CD4 on Th → for MHCII.
CD8 on Tc & Ts → for MHCI.

18. 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

19. 4) Receptor for regulator the function of T & B cells
For complement
For cytokine
For antibody
5) Receptor for unknown function.

20. THANK YOU