Metagonimus yokogawai: a 100-kDa somatic antigen commonly reacting with other trematodes

This study was undertaken to characterize the properties of a 100 kDa somatic antigen from Metagonimus yokogawai. Monoclonal antibodies (mAbs) were produced against this 100 kDa antigen, and their immunoreactivity was assessed by western blot analysis with patients' sera. The mAbs against the 100 kDa antigen commonly reacted with various kinds of trematode antigens, including intestinal (Gymnophalloides seoi), lung (Paragonimus westermani), and liver flukes (Clonorchis sinensis and Fasciola hepatica). However, this mAb showed no cross-reactions with other helminth parasites, including nematodes and cestodes. To determine the topographic distribution of the 100 kDa antigen in worm sections, indirect immunoperoxidase staining was performed. A strong positive reaction was observed in the tegumental and subtegumental layers of adult M. yokogawai and C. sinensis. The results showed that the 100 kDa somatic protein of M. yokogawai is a common antigen which recognizes a target epitope present over the tegumental layer of different trematode species.