Effects of Schistosoma mansoni infection on phagocytosis and killing of Proteus vulgaris in Biomphalaria glabrata hemocytes.

With the use of a fluorescence microassay, in vitro phagocytosis and killing of Proteus vulgaris were measured in hemocytes of NIH albino Biomphalaria glabrata infected with Schistosoma mansoni for 1, 2, 3, or 4 wk. Although hemocytes of infected snails displayed decreased phagocytosis, relative to hemocytes of uninfected snails, at 4 wk postinfection (PI), they exhibited enhanced microbicidal activity at 3 wk PI. No microbicidal activity was detected in the plasma of either infected or uninfected snails.