3. Cell mediated immunity

4. Cell mediated immunity
Types of T cells formed
Helper T cells
Cytotoxic T cells.
Suppressor T cells

5. Lymphokines Low molecular weight regulatory proteins
Lymphokines secreted by lymphocytes
Interleukin 2
Interleukin 3
Interleukin 4
Interleukin 5
Interleukin 6
Granulocyte-monocyte colony stimulating factor, Interferon  .,.

6. FUNCTIONS OF HELPER T CELLS
Specific Regulatory functions of the lymphokines.
Stimulation of growth and proliferation of cytotoxic T cells and suppressor T cells.
Stimulation of B-Cell Growth and Differentiation to Form Plasma Cells and Antibodies.
Activation of the Macrophage System.
Feedback Stimulatory Effect on the T-Helper Cells

7. Functions of Interleukins

8. Cytotoxic T cells

9. Cytotoxic T Cells Are “Killer” Cells
The cytotoxic T cell is a direct-attack cell that is capable of killing microorganism.
The receptor proteins on the surfaces of the cytotoxic cells cause them to bind tightly to the organisms or cells that contain the appropriate binding-specific antigen.

10. secrete perforins that punch holes in the membrane of the attacked cell.
attacked cell swollen ,dissolves thereafter.
cytotoxic cells can pull away from the victim cells and can move on to kill more cells.

11. The cytotoxic cells also play an important role in destroying
cancer cells
heart transplant cells
cells foreign to the person’s own body.

12. Suppress functions of both cytotoxic and helper T cells.
Suppressor T cells:
Suppress functions of both cytotoxic and helper T cells.
Limit the ability of immune system to attack body’s own tissues Called Immune Tolerence.
Suppressor & helper T cells also called as regulatory T cells.

13. Failure of the Tolerance Mechanism Causes Auto-immune Diseases.
Rhematic fever
Glomerulonephritis
Myesthenia Gravis
Systemic lupus erythematosus(SLE)

14. Functions of lymphokines
Growth and proliferation of
Cytotoxic T cells
Suppressor T cells
B lymphocytes (specially interleukins 4,5,6)
Plasma cells
Production of antibodies
Activation of macrophages
Positive feed back effect on Helper T cells themselves
Absence of TH & interleukins→ AIDS

15. CTL Contacts a Tumor Cell
CD8 T Cell
Tumor Cell

16. Membrane Damage to the Tumor Cell

18. Thank-you
Questions ??