Characterization of surface antigens of Trichinella spiralis infective larvae

Infective larvae of Trichinella spiralis were surface‐labelled with radioactive iodine, and the products were characterized biochemically and immunochemically. The labelled material was restricted to two basic subunits: a lentil lectin‐adherent glycoprotein (GP), mol. wt 47K, and a lentil lectin‐non‐adherent protein fraction (P), mol. wt 55K. Both of these form homologous dimers through as yet unspecified covalent bonds to yield GP90 and P105. The GP is further polymerized into higher molecular weight forms by disulphide bond‐dependent associations, suggesting a highly cross‐linked arrangement in the cuticle. To what extent this structure contributes to the overall organization of the cuticle remains to be established. The two labelled surface molecules are immunogenic in the infected host, and do not react with a panel of sera taken from animals chronically infected with other nematode species. The approach therefore offers immediate possibilities for immunodiagnosis in nematode infections, and for a comparative immunochemical study of the surface cuticle of different stages of the same and different nematode species and for studies of the function of the nematode cuticle.