Comparison of proteins of parasite stages of schistosoma mansoni and those of the tissues of the snail vector biomphalaria pfeifferi
Antigen sharing between a parasite and its host is a stimulating facet of host-parasite relationship which is currently receiving considerable attention. The aim of the study was to investigate presence of common proteins in various stages of the parasite, Schistosoma mansoni and its intermediate host, Biomphalaria pfeif.feri. Comparison of protein profiles of extracts of uninfected and infected snail digestive gland, foot, soluble cercarial antigens (SCA) and soluble worm antigen preparation (SWAP) was achieved by native and SDS-PAGE. The study also compared S. mansoni infected snail tissues (day 8 foot, daylS digestive gland and day 32 foot) with the uninfected tissues using native and SDS-PAGE. Immune cross-reactivity between the tissue proteins and antibodies raised against SWAP and SCA was also investigated in Western blots. Five proteins of approximate molecular weights 66 kDa, 46kDa, 26kDa, 16kDa, and 12kDa were found to be common in uninfected, infected samples, SCA and SWAP in SDSPAGE while 178kDa, SOkDa, 2SkDa and 14kDa proteins were found to be common in the samples by native PAGE. When infected and uninfected tissues were compared, a decrease in the intensity of proteins with Mr~178kDa and 44kDa was observed in the digestive gland, 120kDa and 30kDa in the foot. The proteins that cross reacted with anti-SWAP included Mr~ 220kDa, 180kDa, 89kDa, 38kDa and 12kDa in the foot, 76kDa, 46kDa, 22kDa, and 16kDa in the digestive glands. Proteins with approximate molecular weights of 220kDa and 16 kDa in the digestive gland cross reacted with anti-SCA. The study has revealed common proteins and immune cross reactivity between S. mansoni and its intermediate host B. pfeifferi antigens. These proteins could be useful as potential vaccine candidates and in the diagnosis of Schistosomiasis.