Antibodies

A region at the tip of the antibody protein is very variable, allowing millions of antibodies with different antigen-binding sites to exist.

Complex genetic mechanisms evolved which allow vertebrate B cells to generate a diverse pool of antibodies from relatively few antibody genes.

The clonal selection hypothesis is a widely accepted model for the immune system's response to infection.

Isotype class switching is a biological mechanism that changes a B cell's production of antibody from one class to another.

Memory B cells are a B cell sub-type that are formed following primary infection.

The immune system protects organisms from infection first with the innate immune system, then with adaptive immunity.