Common antigenic molecules are found between different parasites and their intermediate hosts.
This antigenic similarity may be applied for serodiagnosis or drug and vaccine development. The
present study was designed to evaluate the antigenic similarity between adult Schistosoma mansoni
and some Egyptian freshwater snails Biomphalaria alexandrina, Lymnea natalensis, and
Physa acuta and the antigenic value in immuno-diagnosis of intestinal schistosomiasis.
Fifteen laboratory-bred infected albino mice were used to obtain adult S. mansoni for adult
crude antigen preparation. Forty-eight laboratory-bred rats were used to prepare hyperimmune
sera by testing seven separated antigens. Crude snails' antigens were prepared from the foot and
visceral parts of the tested snails. Comparing the molecular weight of the tested antigens was
done using SDS-PAGE following hyperimmune rat sera preparation for western blot technique
and ELISA to visualize their immunogenicity and cross-reactivity.
SDS-PAGE and immunoblotting showed the presence of strong similar bands between whole
adult worm antigen and B. alexandrina foot antigens while poor antigenic relationship was revealed
with L. natalensis and P. acuta antigens. B. alexandrina foot antigen was found by ELISA
to be the best antigen to replace S. mansoni crude antigen in immuno-diagnosis of schistosomiasis
in concern to their sensitivity and specificity.