Biochemical and functional antigenic mimicry by a polyclonal anti-idiotypic antibody for chlamydial exoglycolipid antigen.

A vaccine developed by using a genus-specific antigen (Ag) of Chlamydia trachomatis would elicit a wide range of protection against various chlamydial infections. We have produced an anti-idiotypic antibody (Ab2) in guinea pigs which, in rabbits, mimics the immunogenicity of a genus-specific exoglycolipid Ag (GLXA) of C trachomatis. Furthermore, the Ab2 fulfills the functional criteria of an 'internal image' of the nominal Ag: it inhibits the binding of the idiotypic (Id) monoclonal Ab (mAb1) to GLXA, and it induces in rabbits anti-anti-Id antibody (Ab3) which recognizes both the affinity-purified nominal Ag GLXA and whole organisms. Moreover, Ab3 induced by immunization of rabbits with guinea pig Ab2 neutralizes infectious heterologous chlamydiae and prevents in vitro and in vivo infection. Taken together, these results demonstrate functional and biochemical mimicry of the Ab2 for the chlamydial GLXA and suggest that anti-idiotypic Ab to GLXA is a potential candidate vaccine against chlamydia-related diseases.