Comparison of haemolymph proteins from Schistosoma mansoni (Trematoda)-susceptible and resistant Biomphalaria glabrata (Gastropoda).

1. Whole and haemoglobin (Hb)-depleted serum fractions from Schistosoma mansoni-resistant (10-R2) and schistosome-susceptible (PR albino, M-line) strains of Biomphalaria glabrata were studied using sodium dodecyl sulphate-polyacrylamide gel electrophoresis, immunoblotting and protein assays. 2. Whole serum of the PR albino strain had more total protein (11.4 +/- 1.9 mg protein/ml) than the 10-R2 strain (7.8 +/- 3.0 mg protein/ml). 3. There are specific differences in the polypeptide profiles of the Hb-depleted fractions between the 10-R2 and PR albino strains of B. glabrata. 4. Antibodies against whole 10-R2 or PR albino serum reacted similarly when incubated with whole or Hb-depleted snail sera although differences in staining intensities were observed. 5. Antibodies against snail Hb reacted with many proteins in whole sera and Hb-depleted fractions from both B. glabrata strains indicating that they may be Hb-associated polypeptides. 6. Polypeptides in whole or Hb-depleted snail serum are modified by reduction indicating the presence of disulphide bonds.