Carbohydrate-binding plasma proteins from the gastropod Biomphalaria glabrata: Strain specificity and the effects of trematode infection

Abstract

As lectins are believed to mediate non-self-recognition in molluscs, carbohydrate-binding proteins (CBP) from the circulating plasma of the gastropod Biomphalaria glabrata were harvested by affinity chromatography using six different monosaccharides as ligands. Pools of plasma were derived from B. glabrata of either the M line strain, which is susceptible to infection with the PR1 strain of the digenetic trematode Schistosoma mansoni, or from the 13-16-R1 strain, which is resistant to infection. For each strain, plasma was obtained from control snails and from snails exposed to infection 1 or 8 days previously with S. mansoni or the related digenean, Echinostoma paraensei, which is able to develop in either host strain. For control snails, only minor interstrain differences were noted. In M line snails exposed 8 days previously to either parasite, marked changes in CBP populations were observed. Only E. paraensei infections produced comparable alterations in 13-16-R1 snails. The most conspicuous changes noted were the increased production of 80–120 kDa CBP in both strains, 150–210 kDa in 13-16-R1 snails, and 190–210 kDa in M line snails. The results demonstrate 1) interstrain differences in CBP, particularly following exposure to trematodes; 2) that infection provokes increased production and diversity of CBP that bind with greater affinity to the columns; and 3) that snails of the same strain respond differently to the two parasites used.