ABSTRACT
An antigen may be simply defined as a substance that binds to a lymphocyte receptor. In associating with the receptor the antigen may or may not initiate an immune response. Classically, an antigenic molecule is defined by its ability to be bound by a specific antibody (see below), but some antigens fail to stimulate antibody production as part of the immune response. The related term immunogen refers to a substance that induces an immune response when injected into an individual. Antigens may be one of several diverse
At the end of this chapter you should be able to: • Understand what makes one substance more
antigenic than another. • Define ‘epitope’, ‘immunodominant’ and
‘hapten’. • Describe how adjuvants enhance the immune
response. • Describe the basic structure of the
immunoglobulin molecule.
