Type IV(B) Pili Are Required for Invasion but Not for Adhesion of Salmonella Enterica Serovar Typhi Into BHK Epithelial Cells in a Cystic Fibrosis Transmembrane Conductance Regulator-Independent Manner

Microb Pathog. 2011 Nov;51(5):373-7. doi: 10.1016/j.micpath.2011.07.005. Epub 2011 Jul 18.

Abstract

The cystic fibrosis transmembrane conductance regulator (CFTR) has been proposed as an epithelial cell receptor for the entry of Salmonella Typhi but not Salmonella Typhimurium. The bacterial ligand recognized by CFTR is thought to reside either in the S. Typhi lipopolysaccharide core region or in the type IV pili. Here, we assessed the ability of virulent strains of S. Typhi and S. Typhimurium to adhere to and invade BHK epithelial cells expressing either the wild-type CFTR protein or the ∆F508 CFTR mutant. Both S. Typhi and S. Typhimurium invaded the epithelial cells in a CFTR-independent fashion. Furthermore and also in a CFTR-independent manner, a S. Typhi pilS mutant adhered normally to BHK cells but displayed a 50% reduction in invasion as compared to wild-type bacteria. Immunofluorescence microscopy revealed that bacteria and CFTR do not colocalize at the epithelial cell surface. Together, our results strongly argue against the established dogma that CFTR is a receptor for entry of Salmonella to epithelial cells.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Bacterial Adhesion*
  • Cell Line
  • Cricetinae
  • Cystic Fibrosis Transmembrane Conductance Regulator / genetics
  • Cystic Fibrosis Transmembrane Conductance Regulator / metabolism*
  • Epithelial Cells / metabolism*
  • Epithelial Cells / microbiology
  • Fimbriae, Bacterial / genetics
  • Fimbriae, Bacterial / physiology*
  • Humans
  • Salmonella Infections / genetics
  • Salmonella Infections / metabolism*
  • Salmonella Infections / microbiology
  • Salmonella typhi / genetics
  • Salmonella typhi / pathogenicity
  • Salmonella typhi / physiology*
  • Salmonella typhimurium / genetics
  • Salmonella typhimurium / pathogenicity
  • Salmonella typhimurium / physiology
  • Virulence

Substances

  • Cystic Fibrosis Transmembrane Conductance Regulator