Each lymphocyte has thousands of receptor proteins in its membranes. What is the job of these receptor proteins?

These receptor are the means by which lymphocytes sense the presence of antigens in their environment.

Although the general structure of antigen receptors is similar , the variation lies in the antigen binding site. The antigen receptor binds to a portion of the antigens surface that it recognises ( epitope ) .

They have unique antigen specificity because the binding occurs when the structure of the antigen and epitope are complementary.

This initiates the first step towards the activation of antibody production by the lymphocytes.