BIOCHEMICAL AND FUNCTIONAL ANTIGENIC MIMICRY BY A POLYCLONAL ANTIIDIOTYPIC ANTIBODY FOR CHLAMYDIAL EXOGLYCOLIPID ANTIGEN

A vaccine developed by using a genus-specific antigen (Ag) of Chlamydi a trachomatis would elicit a wide range of protection against various chlamydial infections. We have produced an anti-idiotypic antibody (Ab (2)) in guinea pigs which, in rabbits, mimics the immunogenicity of a genus-specific exoglycolipid Ag (GLXA) of C. trachomatis. Furthermore, the Ab(2) fulfills the functional criteria of an 'internal image' of the nominal Ag: it inhibits the binding of the idiotypic (Id) monoclon al Ab (mAb(1)) to GLXA, and it induces in rabbits anti-anti-Id antibod y (Ab(3)) which recognizes both the affinity-purified nominal Ag GLXA and whole organisms. Moreover, Ab(3) induced by immunization of rabbit s with guinea pig Ab(2) neutralizes infectious heterologous chlamydiae and prevents in vitro and in vivo infection. Taken together, these re sults demonstrate functional and biochemical mimicry of the Ab(2) for the chlamydial GLXA and suggest that anti-idiotypic Ab to GLXA is a po tential candidate vaccine against chlamydia-related diseases.