The immunological response of the rat to infection with taeniaeformis. IV. Immunoglobulins involved in passive transfer of resistance from mother to offspring.

Weanling rats born of mothers infected with Taenia taeniaeformis were found to be passively protected against homologous challenge. Cross-fostering of normal suckling rats onto immune mothers established that passive transfer occurred via the colostrum and milk. Immunoglobulin fractions containing gammaA from immune colostrum were fed to 12-14-day-old rats for 4 days via stomach tube. Significant passive protection against challenge with T. taeniaeformis was achieved with gammaA from one of three colostrum pools. The effect of colostral gammaA preparations on the infectivity of freshly hatched oncopheres of T. taeniaeformis was measured by the intra-intestinal inoculation of immunoglobulin solutions into isolated gut loops containing hatched eggs of the parasite. gammaA from one of three pools of immune colostrum caused a significant reduction in the number of parasites which reached the liver. This appears to be the first time that protective activity against a helminth infection has been achieved with gammaA. A fraction of immune colostrum containing both 7Sgamma1 and 7Sgamma2 immunoglobulins was found to confer passive protection when inoculated parenterally. In view of the prolonged period of absorption (ca 18 days) of 7S immunoglobulins from the gut by the suckling rat, it seems likely that these antibodies are primarily responsible for the natural passive transfer of protection from mother to young.