Complement dependent in vitro neutralization of Chlamydia trachomatis by a subspecies-specific monoclonal antibody.

Three murine monoclonal antibodies which combined specifically with Chlamydia trachomatis strain HAR-13 (Serotype A) were characterized. All antibodies cross-reacted with subspecies-specific epitopes in previously undescribed patterns. One of the antibodies showed a complement-dependent partial neutralization of strain HAR-13 in vitro, whereas the remaining two antibodies did not neutralize under any experimental conditions tested. The significance of subspecies-specific antibodies in neutralizing chlamydial infectivity in vivo remains to be determined.