Adult Worm Homogenate of the Nematode Parasite Heligmosomoides polygyrus Induces Proliferation of Naive T Lymphocytes without MHC Restriction

The documented in vitro response of mouse T cells to parasite antigens is typically anamnestic and H-2 restricted. As yet, there have been no confirmed reports of the existence of a non-H-2-restricted, superantigen type of response to the antigens of metazoan parasites. Reported here are data which show that antigens produced by the adult stage of the nematode parasite Heligmosomoides polygyrus (= Nematospiroides dubius) can stimulate naive T cells in vitro to proliferate and produce IL-2. A series of T cell hybridomas has been used to show that adult worm homogenate of H. polygyrus can stimulate parasite antigen naive T cells. This response is independent of the H-2 haplotype of the antigen-presenting accessory cells and does not appear to be influenced by the presence or absence of an H-2 E molecule. However, successful presentation of the H. polygyrus superantigen does require the presence of metabolically active accessory cells and fixation of the accessory cells with paraformaldehyde abrogates the response of the target cells. This discovery has important implications for the study of the role of superantigens in host/parasite interactions and will also help to expand current knowledge about the relationship between chronic intestinal nematodes and the host immune system.