Schistosoma mansoni: modulation of hemocyte surface polypeptides detected in individual snails, Biomphalaria glabrata, following larval exposure.

As an approach to better understand the molecular mechanisms underlying the differential cellular response to larval Schistosoma mansoni observed in Biomphalaria glabrata, we have analyzed hemocyte membrane-associated polypeptides from inbred susceptible and resistant strains of B. glabrata. A combination of techniques involving biotin-labeling of cell surface-exposed polypeptides and a highly sensitive chemiluminescent detection technique has allowed the identification of major polypeptides expressed on nonadherent and adherent hemocyte subpopulations from individual snails and an assessment of the variability in their expression in response to S. mansoni exposure and latex bead injection. Results showed that S. mansoni exposure and latex bead injection differentially modulate the expression of 4 of 10 major hemocyte surface polypeptides with estimated molecular weights of 155/130, 120/110, 85, and 66 kDa. Little correlation was observed between the expression of any given polypeptide and a specific response to S. mansoni exposure. Moreover, the complex pattern of hemocyte surface polypeptides observed in snails subjected to the two treatments suggests that multiple signals may be influencing either the expression of these four polypeptides at the hemocyte surface or the hemodynamic of specific peptide-bearing hemocyte subpopulations released into the circulation. The fact that a natural and an artificial insult in the two snail strains elicit a differential response in the occurrence of these four polypeptides suggests that they may be involved in defense-related activities.