Enterotoxigenic Escherichia coli infection alters intestinal immunity in mice.

Enterotoxigenic Escherichia coli (ETEC) is a major cause of diarrhea in humans and piglets. However, research regarding alterations of intestinal immunity following ETEC infection remains limited and the results controversial. The present study investigated the effects of ETEC on the expression levels of pro‑inflammatory cytokines and innate immune regulators from plasma cells, goblet cells and Paneth cells, and the activation of toll‑like receptor 4-nuclear factor (NF)‑κB and mitogen‑activated protein kinase (MAPK) pathways using reverse transcription‑quantitative polymerase chain reaction and western blot analysis, in a mouse model infected with a porcine isolated ETEC strain. ETEC infection significantly reduced the expression of pro‑inflammatory cytokines in the mouse jejunum (P<0.05). Additionally, ETEC infection significantly affected the expression of immune regulators of plasma cells, goblet cells and Paneth cells in the mouse intestine (P<0.05). ETEC influenced the intestinal immunity via the NF‑κB and MAPK signaling pathways. In conclusion, ETEC colonization affects intestinal immunity as observed in a mouse model. This study provides a greater understanding of the pathogenesis of ETEC infection in animals and humans.