This web page was produced as an assignment for an undergraduate course at Davidson College.

HUMORAL IMMUNE RESPONSE

This part of the immune response is perpetuated by antibodies which are produced by activated B cells.

Antibodies have three ways of attacking and eliminating an invading pathogen

• neutralization – Antibody prevents bacterial adherence to target cells by binding to antigen ligandl
• opsonization – Antibody promotes phagocytosis by coating the outside of the pathogen and making it look extra “tasty” to macrophages and T cells.
• complement cascade activation – Antibody activates complement cascade (see innate immunity), which enhances opsonization and facilitates the lysis of certain bacteria.

B Cell Activation:

The B cell is activated by interaction with a helper T cell and differentiates in to plasma cells that secrete antibody specific to the antigen presented by the T cell. 

This process requires two seperate signals to occur at the same time:

Signal 1 – B Cell receptor crosslinking by the antigen itself

Signal 2 –

• From T cell (thymus dependent)
• CD40/CD40L
• Cytokine signal
• From Ag itself (thymus independent)