another term for antigens
Medical Definition of ANTIGEN. : any substance (as an immunogen or a hapten) foreign to the body that evokes an immune response either alone or after forming a complex with a larger molecule (as a protein) and that is capable of binding with a product (as an antibody or T cell) of the immune response.â anÂ·tiÂ·genÂ·ic \Ëan-ti-Ëje-nik\ adjective.edical Definition of ANTIGEN. : any substance (as an immunogen or a hapten) foreign to the body that evokes an immune response either alone or after forming a complex with a larger molecule (as a protein) and that is capable of binding with a product (as an antibody or T cell) of the immune response.