Lymphatic & Immune System: Clonal Selection & Steps of the Humoral Immune Response

Immunocompetent B cells exposed to antigen. Antigen binds only to B cells with complementary receptors

1) Antigen Recognition

B cell internalizes antigen and displays processed epitope. Helper T cell binds to B cell and secretes interleukin.

2) Antigen Presentation

Interleukin stimulates B cell to divide repeatedly and form a clone.

3) Clonal Selection

Some cells of the clone become memory B cells. Most differentiate into plasma cells.

4) Differentiation

Plasma cells synthesize and secrete antibody. Antibody employs various means to render antigen harmless.

5) Attack