An investigation of the antigens of Ascaris lumbricoides using a radioimmunoassay and sera of naturally infected humans.

Of 5 humans from an Ascaris lumbricoides(var. suum)-endemic area who were positive for Ascaris infection (past or current) when examined by a radioallergosorbent test (RAST) for serum immunoglobulin E, only 1 contained detectable levels of Ascaris specific serum IgG antibodies. These antibodies were not detectable when the radioimmunoassay was replaced with a precipitin assay. There was a wide ringe of molecular weights and isoelectric points of antigens in Ascaris body fluid (ABF) which reacted with antibodies in this infected human. However, unlike the IgE-binding ABF antigens, the IgG-binding ABF antigens were particularly evident in one area of molecular weight and isoelectric point. This human also had IgA and IgM to Ascaris antigens whereas the others had barely detectable amounts.