Effect of peroral anti-bacterial antiserum treatment on intestinal immune parameters of germ-free piglets intragastrically infected with virulent Salmonella typhimurium or enteropathogenic E. coli

Germ-free piglets were orally infected with either enteropathogenic E. coli O55 or a virulent strain of Salmonella typhimurium. Orally applied antiserum against E. coli protected infected animals in spite of the fact that the bacteria were consistently found in mesenteric lymph nodes and other organs. By contrast, the application of an antiserum against S. typhimurium was without any effect on the outcome of infection. The treatment with anti-bacterial antiserum prevented inflammation of ileal mucosa (TNF-α and heat shock protein 65 expression) only in piglets infected with E. coli. A decrease in the frequency of ileal MAC320+ cells was observed in all infected piglets treated with antiserum.