Evaluation of protective immunity of 28KD-GST as a vaccine against experimental Schistosoma mansoni.

ABSTRACT

Schistosoma mansoni GST was purified from adult worm homogenates by affinity chromatography. SDS-PAGE analysis of the purified antigen revealed that SmGST has molecular weight around 28 KD was used as a vaccine in a dose of 25 and 35 microg. Eleven groups of BALB/c mice of 10 mice each were vaccinated by GST. Complete Freund's adjuvant (CFA) and BCG vaccine were used as adjuvant. Booster doses were given after 2 & 4 weeks. Two weeks after the last dose of vaccine, mice were challenged by S. mansoni cercariae. Blood samples were taken 7 weeks post infection for detection of IgGl, IgE and circulating antigens. Then mice were sacrificed for histopathological study of the liver. Highly significant (p > 0.001) increase in the mean optical density of IgGl & IgE in groups vaccinated by 35 microg GST and CFA was demonstrated. On the other hand, highly significant (P < 0.001) decrease in circulating antigen, grnuloma number and size in the same group.