Studies on immune responses to parasite antigens in mice. IV. Inhibition of an anti-DNP antibody response with the antigen, DNP-Ficoll containing phosphorylcholine.

Several nematode parasites contain phosphorylcholine (PC), and mice infected with Ascaris suum and Nippostrongylus brasiliensis produce IgM anti-PC antibodies. PC is a hapten which usually induces highly restricted antibody responses in mice and the conjugate DNP-Ficoll-PC inhibits an adoptive secondary anti DNP antibody response to DNP-flagellin whereas comparable doses of DNP-Ficoll and Ficoll-PC do not. The finding suggests that the restricted anti-PC responses to PC-containing antigens described in the literature may involve a degree of inhibition within the B-cell population (partial tolerance induction), that uni- and multi-cellular parasites of various types may 'utilize' molecules such as PC to induce a state of selective tolerance to parasite antigens, and that such a mechanism may be one means of facilitating survival of the parasites in their hosts and the production of antigenic variants of the parasite.