THE ANTIGENIC RELATIONSHIP BETWEEN SCHISTOSOMA MANSONI AND ITS INTERMEDIATE SNAIL HOST.

Schistosomiasis is a public health problem, in many developing: countries including Egypt, Determination of the antigenic relationship between S mansoni and its intermediate snail host (IMH) Biomphalaria alexandrina can open a new field for diagnosis and control of the dis- ease. In the present study infected and non-infected B. alexandrina foot and visceral hump tissue as well as S. mansion crude Ag (SWAg) were fractionated using SDS-PAGE. It's specific and cross reacted protein fractions were determine using EITB versus experimentally prepared mice hyper immune sera (HIS) versus each antigen. After treatment of fractionated S.mansoni crude worm antigens (SWAg) versus HIS produced after vaccination of mice by the same Ag, 8 kda protein fractions ranged from 35-140 kda were reacted specifically. Treatment of fractionated B.alexandrina infected and non-infected foot and visceral hump Ag versus previous HIS revealed presence of common polypeptides bands between SWAg and non-infected snail antigens. The fraction at 135 kda, 68 kda, were detected in all cases, while that at 40-42 kda and that at 35 kda was diagnosed in SWAg and that of infected snails only. The fraction at 68 kda was reacted specifically between SWAg and all tested fractionated snail antigens either that of foot or visceral hump when they treated separately by HIS of mice vaccinated by each snail A eparately. The fraction at 135 kda was common between SWAg and snail (infected and non-infected) visceral hump antigen. The fraction at the level of 110 kda was diagnosed inSWAg, in non-infected foot antigen and visceral hump Ag. The fraction at the level of 46-48 (da are common between SWAg and snail foot and visceral hump Ag after treated by HIS of mice vaccinated by foot Ag, Presence of common antigenic fractions between snail tissues and Schistosoma species can prefer an easily source of antigen valuable for diaguosis or vaccination as well as can be considered as new tool for determination to the snail IMH of new discovered trematode Darasites.