noun, plural: immunogens
Any substance that stimulates an immune response, such as production of specific antibody or cellular immunity.
An immunogen is a kind of antigen that elicits an immune response. Unlike other types of antigens (such as hapten and tolerogen), immunogen can by itself stimulate an immune response and then serve as the target of such response.
Word origin: From immuno-, immune + –gen, from Gk –genés, born, produced.
Related forms: immunogenic (adjective).
See also: immune response.