The stage-specificity of the IgA response to newborn larva and TSL-1 antigens of

Characterization of human lgA responses to newborn larva (NBL) and TSL-1 antigens was carried out by ELISA assays. Relevant and differential IgA antibody responses to these antigens were detected in humans infected with T. spiralis. The inhibition ELISA results showed that the IgA response to NBL antigens was inhibited significantly by both NBL and TSL-1 antigens and to a lesser extent when phosphorylcholine (PC) was used as inhibitor. In contrast, the IgA response to TSL-1 antigens was inhibited by the homologous antigen and to a lesser extent by the NBL and PC. Thus, the early IgA antibodies developed in trichinellosis patients contained a portion of IgA antibodies directed to PC which is present in TSL-1, A and NBL components. Another portion of antibodies to NBL are directed to other common non-defined epitopes present in TSL-1 and NBL antigens. All together these results suggest that the IgA response to common epitopes in antigens of both stages of the parasite may be useful for early diagnosis and epidemiological studies of human trichinellosis