Studies of escherichia coli in gnotobiotic pigs. II. The immune response.

The immune response of orally infected and parenterally vaccinated (E. COLI 08:K.:H21) gnotobiotic pigs was studied by bactericidal and indirect hemagglutination test methods. The bacterial agglutination test proved to be of no value in this study. The results demonstrated that antibody was detectable within 8 days following oral infection, but the titers remained very low until after the pigs were vaccinated intravenously. The titers of the sera were markedly increased following intravenous vaccination. There was no detectable absorption of antibody from the gut of gnotobiotic pigs fed immune serum at 4 to 6 days of age and no detectable difference between the immune response of these pigs and those not fed serum.