THE EFFECT OF HEMOLYMPH INOCULATION ON TH E DEFENSE-MECHANISM OF BIOMPHALARIA-TENAGOPHILA (ORBIGNY, 1835)

The resistance of B. tenagophila snails to infection by Schistosoma ma nsoni was studied. These snails had been previously inoculated with he molymph talsen from other snails infected by S. mansoni of SJ strain o r by other trematodes. The findings suggest that two types - cellular and humoral - are responsible for the resistance to infection by S. ma nsoni. The cellular response occurred when the snails were inoculated with hemolymph from snails infected by S. mansoni. B. tenagophila inoc ulate with hemolymph from snails infected by furcocercariae without ey e-spot, also showed resistance to the infection by S. mansoni. in this latter case, the degenerated sporocysts were not enveloped by ameboci tary reaction, leading to the conclusion that humoral factors could be involved.