immunogenicity
(IH-myoo-noh-jeh-NIH-sih-tee)
The ability of a substance that contains antigens to cause the body to make an immune response against that substance. The immune system recognizes antigens on the surface of substances it sees as foreign, such as vaccines, bacteria, viruses, or cancer cells, and makes an immune response against them. The strength of an immune response depends on how immunogenic a substance is.