Immunity to experimental cholera. II. Secretory and humoral antitoxin response to local and systemic toxoid administration

The effect of parenteral or intrajejunal administration of formalinized cholera toxoid on antitoxin titers in serum and jejunal washings was studied in dogs with chronic Thiry Vella jejunal loops. In previously immunized dogs toxoid given by either route caused elevated titers of antitoxin in jejunal washings. After parenteral boosting, much of the antitoxin in jejunal washings was probably derived from serum, whereas after intrajejunal boosting, it appeared to be locally derived. In either instance, IgA antitoxin contributed to the intestinal immune response and had the characteristics of secretory IgA. In previously unimmunized dogs jejunal wash antitoxin was not demonstrable after a primary series of intrajejunal toxoid administrations but was demonstrable when the series was repeated four weeks later. After a single intrajejunal toxoid booster, antitoxin was demonstrable in washings within one to three days and peaked at seven days. Thus, the jejunal secretory immunologic system apparently has immunologic memory and is capable of mounting a rapid and brief secondary type response to locally administered antigen.