Recognition of antigens of three different stages of the Trichinella spiralis by antibodies from pigs infected with T. spiralis.

Infective muscle larvae (ML), adults (Ad) and new born larvae (NBL) of Trichinella spiralis express many immunogenic proteins which can elicit a host protective response, and may be useful in the diagnosis of Trichinella infected humans and animals. The present study was carried out to identify T. spiralis antigens recognized by antibodies from pigs infected with T. spiralis. To that end, the crude extracts of ML, Ad, NBL and ML excretory-secretory (E-S) and Ad E-S proteins were analyzed by sodium dodecyl sulfate polycrystalline gel electrophoresis (SDS-PAGE). To identify antigens of T. spiralis that are recognized by host antibodies, crude extracts and E-S proteins were subjected to immunoblot with antisera derived from pigs experimentally infected with 200 or 20,000 T. spiralis ML. Searching for T. spiralis antigens with diagnostic potential, immunoblots showed that all T. spiralis antisera, regardless of the infective dose, recognized common proteins in each examined life stage with molecular weights around 20-27 kDa, 41 kDa and 197-105 kDa. Interestingly, all the common proteins were detected by T. spiralis sera throughout the infection, from 5 days post infection (dpi) to 60 dpi. These results extend our knowledge of specific antigenic components of T. spiralis. The finding of common components among all T. spiralis life stages may be useful in the preparation of parasite antigens for diagnostic use, as these antigens are relevant regardless of infection phase.