Antichlamydial activity of vaginal secretion

Am J Obstet Gynecol. 1995 Apr;172(4 Pt 1):1268-72. doi: 10.1016/0002-9378(95)91491-9.


Objective: The purpose of this study was to investigate the possible antichlamydial activity of vaginal secretion and to partially characterize the inhibitory principle.

Study design: 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.

Results: 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.

Conclusions: 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.

MeSH terms

  • Adolescent
  • Adult
  • Antibodies, Bacterial / analysis
  • Body Fluids / immunology
  • Body Fluids / metabolism
  • Body Fluids / physiology*
  • Cells, Cultured
  • Chlamydia trachomatis / growth & development*
  • Chlamydia trachomatis / immunology
  • Contraceptives, Oral / pharmacology
  • Female
  • Humans
  • Hydrogen-Ion Concentration
  • Immunoglobulin A / analysis
  • Immunoglobulin G / analysis
  • Inclusion Bodies / microbiology
  • Pregnancy
  • Vagina / drug effects
  • Vagina / metabolism*


  • Antibodies, Bacterial
  • Contraceptives, Oral
  • Immunoglobulin A
  • Immunoglobulin G