Vaccination with recombinant paramyosin in Montanide ISA206 protects against Schistosoma japonicum infection in water buffalo

Background Schistosomiasis japonica is a zoonosis and presents significant public health problems in China and the Philippines. Vaccines targeting domestic animals constitute attractive control measures. Methods We conducted three vaccine trials to evaluate the protective efficacy of recombinant full-length paramyosin (rSj97) in water buffalo. Animals were immunized with 3 doses of rSj97 adjuvanted with ISA206 at 250 μg/dose or 500 μg/dose at 4 wk intervals before challenge with 1000 Schistosoma japonicum cercariae. The primary outcome was worm burden assessed by portal perfusion 8–10 weeks post challenge. Safety measures included weight, temperature, body condition score, hemogram and routine assays for hepatic and renal function. Results The three-dose regimen was well tolerated in all three trials. In the first trial, vaccinated buffalo had 51.5% lower worm burden post challenge compared to controls. In the second trial, buffalo immunized with 500 μg/dose of rSj97 had 57.8% lower worm burden compared to controls (p = 0.026). A similar but not significant reduction (60.9%) was observed with animals administered with 250ug rSj97/dose. In the third trial, buffalo immunized with a 500 μg/dose of rSj97 had 57.8% lower worm burden compared to controls (p = 0.014). Conclusions These findings indicated that rSj97 is a safe and promising vaccine candidate for schistosomiasis japonica in water buffalo.