Gender-specific and pair-dependent glycoprotein antigens of Schistosoma mansoni

Gender-specific and pair-dependent glycoprotein antigens of Schistosoma mansoni have been identified. Concanavalin A-binding glycoproteins of unisexually-and bisexually-reared male and female worms were labeled in vitro with 35S-methionine or 125iodine, and the two-dimensional maps of their polypeptides compared. The total protein compositions of male and female worms were very similar. In contrast, the patterns of glycoproteins immunoprecipitated by antisera from mice chronically infected with only male, only female, or both male and female worms were distinctive, indicating that the immune response elicited by the glycoproteins of male and female S. mansoni varied with the type of infection. Radioiodinated cercarial and egg proteins were also studied. Several polypeptides of cercariae and eggs, and 11 of 32 antigenic worm glycoproteins were recognized only by the antiserum from bisexually-infected mice, not by the antisera from unisexually-infected mice. These pair-dependent antigens may be relevant to the immune mechanisms involved in pathogenesis and resistance to reinfection.