The vaccine efficacy of native paramyosin (Sj-97) against Chinese Schistosoma japonicum.

One of the promising anti-schistosome vaccine candidates currently under investigation is paramyosin, a 97-kDa myofibrillar protein located in the muscles and tegument of schistosome worms. Here we describe the results of two vaccination/challenge experiments undertaken in mice using native paramyosin isolated from adult worms of a Chinese strain of Schistosoma japonicum. In both sets of experiments, a relatively low but consistent and significant reduction in worm burden was evident in mice vaccinated subcutaneously with S. japonicum paramyosin and Freund's adjuvant. In contrast, intraperitoneal vaccination of mice with Chinese strain S. japonicum paramyosin without adjuvant did not result in any reduction in worm numbers when compared with a saline control group. These data contrast with the impressive protection figures reported by another group who used a similar intraperitoneal vaccination protocol with native paramyosin extracted from Philippine strain S. japonicum.