The immune response of the definitive hosts to diphyllobothriid antigens.

It was established that antigens of diphyllobothriids entered the organisms of nestlings of gulls (Larus fuscus) and terns (Sterna hirundo) through the intestine. In terns, the most intensive neutralization of parasite antigens was found in the intestine inducing a weak response of the immune system. In gulls, there was no complete neutralization of the parasite antigens in the intestines. The antigens penetrated into the blood stimulating a response of the immune system. The intensity of the local immunity of terns seems to result from the absence of invasion in adult birds.