Natural and acquired immunity factors inhibiting penetration of some hexacanth embryos through the intestinal barrier.

Abstract

EVIDENCE that immunity to taeniid infestations in the intermediate host may be encountered first when embryos attempt to penetrate the small intestinal wall soon after hatching was recently reviewed by Froyd and Round1. They were able by oral dosing with eggs of Taenia saginata to infect young calves, but not older animals, when the majority of the latter were already infected. They were able, however, to establish infections in 13 of 26 older animals by subcutaneous and intramuscular injection of artificially batched and activated embryos. They suggested that the intestinal phase of immunity was thus successfully by-passed.