Page 137 - MNU microbiology theoritical 2025

General Microbiology & Immunology (PM 401) Second level Semester 4 2024/2025

1. Antigen Recognition: B cells

recognize and bind to specific

antigens using their B cell receptors

(BCRs).

2. Antigen Processing: The B cell

internalizes and processes the

antigen, presenting it on MHC class

II molecules.

3. T Cell Help: Helper T cells

recognize the antigen and provide

activation signals to the B cell and

release cytokines.

4. Clonal Expansion: The B cell proliferates and differentiates into plasma cells

(effector B cells) and memory B cells.

5. Antibody Production: Plasma cells secrete antibodies that target and

neutralize the antigen.

Activation of T cells

While in the thymus, the developing T cells start to express T cell receptors (TCRs)

1. Antigen Presentation: Dendritic cells or other antigen-presenting cells capture

and process antigens, then present them on MHC molecules (MHC I for

cytotoxic T cells, MHC II for helper T cells).

2. T Cell Receptor Recognition: T cells recognize the antigen-MHC complex

through their T cell receptors (TCRs).

General Microbiology & Immunology (PM 401) theoretical handbook Page 126