The anti-idiotypic antibody to chlamydial glycolipid exoantigen (GLXA) protects mice against genital infection with a human biovar of Chlamydia trachomatis

Despite more than three decades of anti-chlamydial vaccine research and imp roved Vaccine strategies with new technologies, no vaccine candidate has pr otected against heterologous challenge, nor at more than one site of infect ion. The majority of experimental anti-chlamydial vaccines to date have tar geted the chlamydial major outer membrane protein (MOMP). Many MOMP-directe d vaccine candidates have been highly immunogenic, but have failed to prote ct against infectious challenge. We have extended our previous studies of a different anti-chlamydial vaccine, a monoclonal anti-idiotypic antibody (a nti-Id; mAb2) which is a molecular mimic of the chlamydial glycolipid exoan tigen (GLXA). The present studies demonstrate that the mAb2 Vaccine is prot ective in a murine genital infection model utilizing a human urogenital str ain. After either mucosal (oral or intranasal) or systemic (subcutaneous) i mmunization with the poly (lactide) encapsulated-mAb2 to GLXA, C3H/HeJ mice were significantly protected against topical vaginal challenge with Chlamy dia trachomatis (K serovar; UW-31). Reduced vaginal shedding of organism an d genital tract inflammation were associated with GLXA-specific and/or anti -EB neutralizing serum antibody. Our results demonstrate that the anti-Id ( mAb2) vaccine is protective against an additional human biovar of C. tracho matis in C3H/HeJ mice, which are allogeneic to the source of mAb2 (BALB/c). (C) 2001 Elsevier Science Ltd. All rights reserved.