Characterization of Trichinella spiralis antigens sharing an immunodominant, carbohydrate-associated determinant distinct from phosphorylcholine.

The biochemical and immunochemical characteristics of T. spiralis molecules (group II antigens) sharing an immunodominant epitope were examined. Six major proteins, ranging from 43-68 kDa, and from pI 5.0-6.3, express the determinant. Together, they account for at least 3% by weight of the total protein in L1 larval homogenate. The antigens are glycosylated. Following periodate oxidation, they reacted with biotin aminocaproyl hydrazide, and treatment with trifluoromethanesulfonic acid decreased their Mr. Deglycosylated group II antigens lost immunoreactivity with a monoclonal antibody specific for the determinant, and oligosaccharides released by treatment with mild base blocked binding of the monoclonal antibody to native antigens. The determinant on one of the group II antigens (43 kDa) was removed by N-glycanase. Neither phosphorylcholine nor antibody to phosphorylcholine interfered with monoclonal antibody binding to native group II antigens. Together, these results suggest that the immunodominant group II antigen epitope is associated with N- and O-linked oligosaccharides, and that it is not phosphorylcholine.