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 micro g. 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 and 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 IgG1, 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 IgG1 and IgE in groups vaccinated by 35 micro g 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