The Effect Of Immunizing Swiss White Mice With Snail Soluble Proteins And Challenging Them With Schistosoma Mansoni -and-challenging-them-with-schistosoma-mansoni

Abstract

Schistosomiasis infects approximately 700 million people in 74 endemic countries. It causes high morbidity. Although the drug of choice, Praziquantel is effective against Schistosoma mansoni, there is a problem of rapid re-infection, high cost and risk of drug resistance. A vaccine would have a long term effect and would complement chemotherapy, but, there is no Schistosomiasis vaccine in the market, although many candidate vaccines have been developed and tested. The intermediate host of S. mansoni, the snail, has been found to share proteins with the parasite. The present study tested the effect of immunizing Swiss white mice with soluble proteins prepared from the snail intermediate host, Biomphalaria pfeiferri. DG was prepared from the digestive gland and RT from the rest of the snail body. The immunized mice were challenged with Schistosoma mansoni, and worm reduction, cytokine responses, IgG responses and gross pathology analyzed. Worm reduction in RT was 60.5% while that of DG was 43.3%. RT stimulated significantly higher responses of interferon gamma and interleukin-5 compared to DG. RT produced higher IgG responses than DG. Also, RT had more reduced pathology compared to DG. These results imply that both cellular and humoral responses were involved in the protection against S. mansoni, as shown by high production of Interferon gamma, Interleukin 5 and IgG. This resulted to reduced worm counts and reduced pathology. Although the two soluble proteins were protective, RT was a better in terms of higher worm reduction, higher cellular and humoral protective responses and least pathology