Neutralizing Antibody Responses to Chlamydia trachomatis in Women and Associations with Chlamydia Outcomes.

We assessed neutralizing antibody responses in a well-characterized cohort of 60 women with different Chlamydia trachomatis infection outcomes noted at a treatment visit and 3-month follow-up. We found varying rates of neutralization (inhibition of C. trachomatis) in sera at different dilution levels and varying neutralizing antibody titers across outcomes. Median neutralization rates were significantly higher in sera at high dilutions (1:320-1:1280) from women with spontaneous resolution versus persisting infection before treatment (all P< .05). These findings suggest that neutralizing antibody responses may contribute to protective immunity against chlamydia.