Excretory/secretory antigens of adult Paragonimus ohirai recognized by a monoclonal antibody.

An IgM monoclonal antibody (mAb) that reacted with the gut epithelium and luminal contents of adult Paragonimus ohirai was prepared from a mouse immunized with the excretory/secretory (ES) products of the parasite. The mAb reacted with the same sites not only of immature worms and newly excysted juveniles of P. ohirai, but also of adult worms of other Paragonimus species, such as P. westermani and P. miyazakii. The mAb did not react with adult antigens prepared from any other helminth parasites. Thus, the mAb is a genus-specific antibody against the gut-associated antigen. Immunoblotting revealed that two antigens with molecular masses (M(r)s) of 27 and 29 kDa were present in the ES products of adult P. ohirai, whereas four antigens with M(r) 27, 29, 36, and 38 kDa were detected i adult worm extract. Partially purified fractions containing acidic and neutral cysteine proteinases have 27 and 29 kDa protein molecules reactive with the mAb. The possibilities that the 36 and 38 kDa antigens may be precursors of these proteinases are discussed.