Presence of non-Fab IgE binding molecules in the intestinal nematode parasite of mice Heligmosomoides polygyrus.

Unsuccessful attempts to identify serum parasite-specific immunoglobulin E (IgE) responses in mice following infections with the intestinal nematode parasite Heligmosomoides polygyrus prompted us to explore the possibility that IgE bound within the parasite antigen could account for the false-positive results observed. A live-worm ELISA was developed. Following incubation, irrelevant IgE monoclonal antibody to DNP, IgE present in normal mouse serum, as well as IgE in immune serum were independently identified within live adult worms in this H. polygyrus-modified ELISA. It was concluded that in addition to parasite-specific IgE binding to H. polygyrus, the parasite may attract both parasite-specific and non-parasite-specific IgE via non-Fab IgE-binding molecules.