Immune responses of rats to live Vibrio cholerae: antibodies in serum and intestinal secretions

Abstract

Following injection of live Vibrio cholerae into the small intestine of rats, antibodies appear in the serum and mucus secretions associated with the intestinal surfaces. In contrast to oral immunization, single pulses given by this route cause primary and secondary agglutinating and vibriocidal antibody responses; they are slower to develop but similar to those induced by intravenous injection of 10-fold lower doses of the organisms. However, the intestinal route of injection appears to favour local formation of agglutinating antibodies that are directly transferred to the mucus secretions; it is likely that these are of the sIgA class. Evidence has also been presented which suggests that intestinal injection causes formation of antibodies which inhibit agglutination of V. cholerae by type-specific antiserum; these inhibitory effects are eliminated if the reaction is carried out in the presence of diluted normal rabbit serum rather than saline.