Antichlamydial activity of vaginal secretion.

Abstract

The purpose of this study was to investigate the possible antichlamydial activity of vaginal secretion and to partially characterize the inhibitory principle. Vaginal secretions obtained from 156 women attending a family planning or gynecologic outpatient clinic for contraceptive advice were studied for the influence on the inclusion formation of Chlamydia trachomatis in cycloheximide-treated McCoy cell cultures. Vaginal secretions from 156 women inhibited the inclusion formation of Chlamydia trachomatis. The inhibition was concentration dependent and the inhibitory principle had a molecular weight of < 10,000 d. It was heat labile. It was not related to antichlamydial antibodies in vaginal secretions. Only three (2%) of the women had a positive culture for Chlamydia trachomatis. Three had immunoglobulin A and three had immunoglobulin G antichlamydial antibodies in vaginal secretions. Secretions of those with a vaginal pH of 3.5 to 4.5 decreased the chlamydial inclusion count by 75% compared with controls. The corresponding percentage for those with a pH of 5.0 to 6.0 was 48% and for those with pH > 6 was 33%. Vaginal secretions of oral contraceptive users and nonusers did not differ in the capacity to decrease the chlamydial inclusion count, p > 0.01. When vaginal secretions were added to McCoy cell cultures infected by Chlamydia trachomatis, the chlamydia inclusion number decreased. There was a correlation between pH of the vaginal secretion and the inhibitory principle. Oral contraceptive use had no influence on the inhibition.