Shared epitope for monoclonal IR162 between Anisakis simplex larvae and Clonorchis sinensis and cross-reactivity between antigens.

IR162 is a rat monoclonal IgE antibody (mAb). In the investigation of rat IgE production, the antigens recognized by IR162 (IR-Ags) were found to be expressed by a variety of helminthic parasites. By western blot analysis, IR162 detected bands in crude extracts of Anisakis simplex larvae, Clonorchis sinensis, Paragonimus westermani, plerocercoids of Spirometra mansoni, and Toxocara canis. Excretory-secretory material from A. simplex larvae also contained a protein recognized by IR162. IR162 mAb obtained from both Serotec and Zymed recognized identical bands of A. simplex larvae. Sandwich enzyme-linked immunosorbent assay analysis indicated that both IR-Ags of A. simplex larvae (IR-As) and C. sinensis (IR-Cs) were important antigens with respect to induction of specific IgG in human infections with these 2 organisms. Even though minimal cross-reaction between IR-As and IR-Cs was observed using sera from infected individuals, these results indicate that IR-Ags are found in the parasites examined, that IR-As and IR-Cs are the antigens that induce specific antibody in natural infection, and that the epitope that binds IR162 is shared by A. simplex larvae and C. sinensis.