Observation on protection by immunization with recombinant BCG-Sj26GST vaccine of Schistosoma japonicum

Objective To investigate protection by immunization with recombinant BCG-Sj26GST vaccine and against challenge with cercariae of Schistosoma japonicum(Sj). Methods BALB/C mice were immunized subcutaneously by 106 and 108 CFU vaccine, respectively, challenged with Sj cercariae at 8 w of immunization and killed at 6 w of infection to count rate of reduced worm burdens and rate of reduced eggs number, to observe pathological changes of liver under the light microscope, to measure the circumference and area of egg granulomas and to examine the level of CAg? IgG and its subclasses, PBS and BCG were served as control. Results In the groups of immunization, the rates of reduced worm burdens were 16.64%～46.20%, the rates of reduced egg number were 55.75%～60.50%,pathological changes of the liver were remarkably lightened, average circumference and average area reduced obviously, the level of IgG and IgG2a increased apparently, that of CAg of 108 CFU group increased remarkably. Conclusions rBCG-Sj26GST vaccine of Schistosoma japonicum is a new type of more ideal vaccine and deserves further study.