Lectin-carbohydrate binding may be involved in the recognition of
Schistosoma mansoni
sporocysts by haemocytes of
Biomphalaria; therefore, we tested if this interaction is associated with snail resistance against
Schistosoma infection. In vitro data showed that most of the
S. mansoni sporocysts cultured with haemocytes from
Biomphalaria glabrata
BH, a highly susceptible snail strain, had a low number of cells that adhered to their tegument and a low mortality rate. Moreover, the addition of N-acetyl-D-glucosamine (GlcNAc) did not alter this pattern of adherence and mortality. Using haemocytes and haemolymph of
Biomphalaria tenagophila
Cabo Frio, we observed a high percentage of sporocysts with adherent cells, but complete encapsulation was not detected. Low concentrations of GlcNAc increased haemocyte binding to the sporocysts and mortality, which returned to basal levels with high concentrations of the carbohydrate. In contrast, haemocytes plus haemolymph from
B. tenagophila Taim encapsulated cellular adhesion index of level 3 and destroyed over 30% of the
S. mansoni sporocysts in culture. Interestingly, the addition of GlcNAc, but not mannose, to the culture medium resulted in the significant inhibition of cellular adhesion to the parasite tegument and the reduction of parasite mortality, suggesting that GlcNAc carbohydrate moieties are important to the recognition of
S. mansoni by
B. tenagophila Taim
