Production of heterogeneous carbohydrate-binding proteins by the host snail Biomphalaria glabrata following exposure to Echinostoma paraensei and Schistosoma mansoni

Hemolymph lectins may play an important role in the internal defense responses of gastropods to parasites. Two groups of known carbohydrate- binding polypeptides, of 150-220 kDa (designated as group 1 molecules, or G1M) and of 75-130 kDa (group 2 molecules, or G2M), were harvested from pooled plasma samples of Biomphalaria glabrata using affinity chromatography and examined using 2-dimensional electrophoresis. Plasma samples were derived from control snails or snails exposed 8 days earlier to the trematodes Echinostoma paraensei or Schistosoma mansoni. Plasma of control and S. mansoni-exposed snails contained little or no G1M, whereas plasma from E. paraensei-infected snails contained G1M covering a broad pI spectrum. G2M resolved as 1-2 isoforms in control plasma and up to 4 relatively faint isoforms in plasma from S. mansoni-exposed snails, and as 5-6 resolvable isoforms in plasma from E. paraensei-infected snails. Plasma from individual snails contained as many as 5 G2M polypeptides following exposure to E. paraensei. Exposure to trematode larvae stimulated production by B. glabrata of increased abundance and diversity of carbohydrate-binding proteins. The 2 trematode species provoked different responses, and 2 B. glabrata strains studied (M line and 13-16-R1 strains) differed from one another in their responses.