T Cells And B Cells

Question 1

Effector functions of t cells

Answer 1

1. Delayed hypersensitivity
2. Cytotoxicity

Question 2

Delayed hypersensitivity

Answer 2

1. T cells are produced against antigen pf intracellular microorganism eg mycobacteria
2. Mediated by Mq and CD4 cells particularly TH1 subset
3. Imp interleukins secreted are: vIFN
   Mq activation factor
   Mq migration inhibitory factor
4. CD4 produces interleukins and Mq which cause delayed type of hypersensitivity

Question 3

Cytotoxicity

Answer 3

1.T cells recognize the intracellular antigens processed by any nucleated cell and present it along MHC-1
2.Tc cells are involved in destruction of virus infected cells and tumor cells.
3. Releases perforin: destroy cell memb
Granzymes: degrading enzymes
4. Fas- Fas ligand interaction apoptosis
5. After killing virus infected cell , t cell itself is not damaged and continues to kill other virus infected cells

Question 4

Regulatory functions of t cells

Answer 4

1. Ab production:
   T cell dependent response: all classes of ab are produced
   T cell independent response: IgM is made
2. Suppression of certain responses: suppressor T cells down regulate the immune response including auto immune reaction

Question 5

Functions of CD4/Helper t cells

Answer 5

1. HELPS in activating mqs and to kill intracellular bacteria through vIFN
2. RECOGNIZES antigenic peptides that are processed by APCs and presented along MHC-2
3. AFTER antigenic stimulus, helper t cells differentiate into either: TH1 OR TH2 subset
4. SECRETES specific cytokines that modulate the humoral and cellular responses respectively
5. HELPS CD8 t cells to become activated cytotoxic t cells through production of IL 2
6. HELPS b cells to develop into plasma cells through IL-4, IL 5 which then secretes antibody

Question 6

Function of CD8/ Cytotoxic t cells

Answer 6

1. KILLS virus infected cell and tumor cells and cells of allografts
2. Memory t cells provides secondary immune response.

Question 7

Function of b lymphocyte

Answer 7

1. Host defense mechanism: opsonize the bacteria, neutalizes toxins and viruses
2. Antigen presenting function- b cells can process and present antigen to t cells
3. Imp role in humoral immune response
4. End result of activation is production of plasma cells that produce large amt of ig specific for epitope