Humoral Immunity in the Gut Selectively Targets Phenotypically Virulent Attaching-and-Effacing Bacteria for Intraluminal Elimination

Cell Host Microbe. 2015 May 13;17(5):617-27. doi: 10.1016/j.chom.2015.04.001. Epub 2015 Apr 30.


Virulence factors expressed by enteric bacteria are pivotal for pathogen colonization and induction of intestinal disease, but the mechanisms by which host immunity regulates pathogen virulence are largely unknown. Here we show that specific antibody responses are required for downregulation of virulence gene expression in Citrobacter rodentium, an enteric pathogen that models human infections with attaching-and-effacing bacteria. In the absence of antibodies against the pathogen, phenotypically virulent C. rodentium, accumulated and infected the epithelium and subsequently invaded the lamina propia, causing host lethality. IgG induced after infection recognized virulence factors and bound virulent bacteria within the intestinal lumen, leading to their engulfment by neutrophils, while phenotypically avirulent pathogens remained in the intestinal lumen and were eventually outcompeted by the microbiota. Thus, the interplay of the innate and adaptive immune system selectively targets virulent C. rodentium in the intestinal lumen to promote pathogen eradication and host survival.

Publication types

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

MeSH terms

  • Animals
  • Antibodies, Bacterial / immunology
  • Citrobacter rodentium / growth & development*
  • Citrobacter rodentium / immunology*
  • Disease Models, Animal
  • Enterobacteriaceae Infections / immunology
  • Enterobacteriaceae Infections / microbiology
  • Gastrointestinal Tract / immunology*
  • Gastrointestinal Tract / microbiology*
  • Immunity, Humoral*
  • Immunoglobulin G / immunology
  • Mice, Inbred C57BL
  • Neutrophils / immunology
  • Neutrophils / microbiology
  • Phagocytosis
  • Virulence
  • Virulence Factors / immunology*
  • Virulence Factors / metabolism*


  • Antibodies, Bacterial
  • Immunoglobulin G
  • Virulence Factors