Neutralizing Antibody Responses to <i>Chlamydia trachomatis</i> 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 vs persisting infection before treatment (all P < .05). These findings suggest that neutralizing antibody responses may contribute to protective immunity against chlamydia.