Activate Extraintestinal Antibody Response and Provide Anti-Infective Immunity.

Abstract

The effects of intestinal microflora on extraintestinal immune response by intestinal cytokines and metabolites have been documented, but whether intestinal microbes stimulate serum antibody generation is unknown. Here, serum antibodies against 69 outer membrane proteins of, a dominant bacterium in the human intestine, are detected in 141 healthy individuals of varying ages. Antibodies againstouter membrane proteins are determined in all serum samples tested, and frequencies of antibodies to five outer membrane proteins (OmpA, OmpX, TsX, HlpA, and FepA) are close to 100%. Serum antibodies againstouter membrane proteins are further validated by Western blot and bacterial pull-down. Moreover, the present study shows that OstA, HlpA, Tsx, NlpB, OmpC, YfcU, and OmpA provide specific immune protection against pathogenic, while HlpA and OmpA also exhibit cross-protection againstinfection. These finding indicate that intestinalactivate extraintestinal antibody responses and provide anti-infective immunity.