Roles of glycoproteins and oligosaccharides found in human vaginal fluid in bacterial adherence

Nithya Rajan*, Qing Cao, Byron E. Anderson, Denise L. Pruden, Julia Sensibar, James L. Duncan, Anthony J. Schaeffer

*Corresponding author for this work

Research output: Contribution to journalArticle

34 Scopus citations

Abstract

Adherence of type 1-piliated Escherichia coli to carbohydrate structures of vaginal mucosa plays a major role in the pathogenesis of ascending urinary tract infections in women. Colonization of the vaginal introitus is influenced by interactions between pathogens, vaginal fluid, and vaginal epithelium. In this study, the type and amount of carbohydrates and glycoproteins present in vaginal fluid were determined. Free and protein- bound oligosaccharides in vaginal fluid specimens were analyzed by fluorophore-assisted carbohydrate electrophoresis (FACE) and high-pressure liquid chromatography (HPLC). Two-dimensional electrophoretic separations of vaginal fluid glycoproteins were performed together with bacterial overlay assays. The results of FACE showed that the majority of the oligosaccharides are in the free state and the bound oligosaccharides are undetectable. HPLC analysis of free sugars revealed glucose as the major sugar (3.3 ± 0.3 mM), and the concentrations of mannose and glucosamine were 0.065 ± 0.04 and 0.02 ± 0.001 mM, respectively. Radiolabeled E. coli bound three vaginal fluid glycoproteins with the following molecular masses and pIs: 82 kDa and pI 5.5, 55 kDa and pI 4.5, and 55 kDa and pI 6.5. The binding was inhibited by mannose and by deglycosylation of the proteins prior to the overlay assay. One of these putative receptors was identified to be the heavy chain of secretory IgA (S-IgA). These data suggest that the free mannose in the fluid is less than that required to affect E. coli-epithelial cell binding interactions and that S-IgA may bind E. coli in the vaginal introitus.

Original languageEnglish (US)
Pages (from-to)5027-5032
Number of pages6
JournalInfection and immunity
Volume67
Issue number10
DOIs
StatePublished - 1999

ASJC Scopus subject areas

  • Parasitology
  • Microbiology
  • Immunology
  • Infectious Diseases

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