1. T-cell Immunity
Dr Farzana Salman

2. T- Cells
T cell constitute 65% to 80% of the recirculating pool of the small lymphocytes.
Located in the inner subcortical region
Long life span---- months or years
Classified into Three types
Helper T cells
Cytotoxic T cells
Suppressor T cells

3. Antigen Presenting Cells

4. Antigen Presenting Cells
Macrophages
B lymphocytes
Dendritic cells

5. MHC Proteins Class I MHC proteins --- Cytotoxic T cells
(CD-8 Lymphocytes)
Class II MHC proteins--- Helper T cells
(CD-4 Lymphocytes)

7. Helper T Cells Most numerous of the T cells
They help in the function of immune system
Protein mediators--- Lymphokines

8. Lymphokines Interleukin – 2 Interleukin - 3 Interleukin- 4
Granulocyte-monocyte colony stimulating factor.
Interferon-Y

9. Functions of Helper T cells
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 helper cells themselves.

10. Cytotoxic T cells

11. Suppressor T cells
Capable of suppressing the functions of both cytotoxic and helper T cells.
Immune tolerance

12. Autoimmune diseases Rheumatic fever Glomerulonephritis.
Myasthenia gravis
Lupus erythematosus

14. Active Immunity Immunization
Injecting dead organisms----- Typhoid fever, Whooping cough, Diphtheria,Bacterial diseases.
Toxins treated with chemicals --- Tetanus, Botulism
Live attenuated organisms---- Small pox,yellow fever,poliomyelitis,measles,viral diseases.

15. Passive Immunity Infusing antibodies, activated T cells or both.
Antibodies to 3 weeks
Activated T- cells---- Few weeks if transfused from
another person
Few hours to few days if
transfused from an animal.

16. Active versus Passive Immunity
Active immunity is resistance induced after contact with foreign antigens
Resistance is long term
Slow onset especially primary response
Passive immunity is resistance based on antibodies preformed in another host.
Prompt availability of large amounts of antibodies
Short life span