The immunogenic effect of purified antigens of B. alexandrina against S. mansoni in experimental animals (II) as measured by the histopathological changes in the liver.

It can be safely said that up till now, no method of vaccination (including recent genes encoding vaccines) has yet proved to be totally effective since they gave partial and low levels of protection against S. mansoni infection. The objective of this work is to try testing the immunogenic effect of two purified non infected B. alexandrina hepatopancreas through histopathological changes in liver of Swiss albino mice (15-20 gm). Gel filtration chromatography was used to fractionate the crude antigen into five fractions followed by re-fractionation and determination of their molecular weights by sodium dodecyl sulphate polyacrylamide gel electrophoresis (SDS-PAGE). Four dilutions of Fiv (20000-29000 daltons) and Fv (20000-24000 daltons) were injected in two groups of mice (33 each) at weekly intervals and another control group was injected with phosphate buffer saline (PBS) in the same manner. Sacrification was done seven weeks from infection with 100 S. mansoni cercariae through immersion method. The results revealed that there is marked histopathological changes in liver of the control group in comparison to the two vaccinated groups which appear more or less normal with slight inflammatory infiltrate.