Antigenic differences between Trichinella spiralis and T. pseudospiralis detected by monoclonal antibodies.

Antigenic differences between Trichinella spiralis and T. pseudospiralis were established using two monoclonal antibodies (mAbs) that show different specificities to muscle larvae of the two variants. Enzyme-linked immunosorbent assay (ELISA) revealed that mAb 3G6 reacts positively against T. spiralis, T. nelsoni, T. nativa and T. pseudospiralis, whereas mAb 3E10 does not react with T. pseudospiralis under the same experimental conditions. These antigenic differences were confirmed after preabsorption of the antibodies with serial dilutions of extracts of T. spiralis or T. pseudospiralis muscle larvae. The indirect immunofluorescence technique showed that the antigen corresponding to mAb 3G6 is located in the stichosomes and the cuticle surface of both T. spiralis and T. pseudospiralis. In contrast, mAb 3E10 positively stained cryostat sections of T. spiralis, forming a dense reaction product on the surface of the whole larvae and the surrounding capsule. This antibody can be quite useful as a specific probe for distinguishing T. spiralis from T. pseudospiralis in taxonomic studies. Using an avidin-biotin system, we could prove that mAb 3G6 recognizes an excretory/secretory-type antigen.