title: Antimicrobial components of vaginal fluid.
abstract: OBJECTIVE
  We examined the antimicrobial activity and composition of vaginal fluid.
  
  
  METHODS
  Vaginal fluid from preweighed tampons was assayed for pH, lactic acid, and antimicrobial polypeptides. The fluid was also fractionated by molecular filtration. Antimicrobial activity of whole fluid was determined against representative resident and exogenous microbes, and its fractions were tested against Escherichia coli.
  
  
  RESULTS
  Vaginal fluids (5/5 donors) were permissive for Lactobacillus crispatus and vaginalis and Candida albicans, but not for Escherichia coli, Streptococcus group B, and Lactobacillus jensenii in three of five donors. The antimicrobial activity against E coli was predominantly in a <3-kd fraction and correlated with both low pH and high lactic acid content. Compared with a matched pH buffer, lactic acid markedly suppressed the growth of E coli. Concentrated 2- or 5-fold, the protein-rich fraction was active against E coli.
  
  
  CONCLUSIONS
  Vaginal fluid exerts selective antimicrobial activity against nonresident bacterial species. The activity is mediated by lactic acid, low pH, and antimicrobial polypeptides.
authors.affiliation: Department of Medicine and Pathology, School of Medicine, University of California, Los Angeles 90095-1690, USA.
authors.forename: Erika V
authors.initials: EV
authors.lastname: Valore
authors.forename: Christina H
authors.initials: CH
authors.lastname: Park
authors.forename: Sorina L
authors.initials: SL
authors.lastname: Igreti
authors.forename: Tomas
authors.initials: T
authors.lastname: Ganz
mesh_terms: D000328:Adult; D000890:Anti-Infective Agents / Q000032:analysis*; D005260:Female; D006801:Humans; D006863:Hydrogen-Ion Concentration; D019344:Lactic Acid / Q000494:pharmacology; D008970:Molecular Weight; D010455:Peptides / Q000032:analysis*; D011506:Proteins / Q000032:analysis; D014621:Vagina / Q000737:chemistry / Q000276:immunology* / Q000382:microbiology
chemical_list: D000890:Anti-Infective Agents; D010455:Peptides; D011506:Proteins; D019344:Lactic Acid