Identification and distribution of carbohydrate moieties on the salivary glands of Rhodnius prolixus and their possible involvement in attachment/invasion by Trypanosoma rangeli

In the present study, FITC-labelled lectins (WGA, Con A, PNA, HPA, and TPA) were utilized to investigate carbohydrate residues on the surface of Rhodnius prolixus salivary glands. The results revealed that the salivary glands are rich in carbohydrate moieties and the diversity in binding pattern of particular lectins showed the presence of specific carbohydrate residues in the basal lamina, muscle, and cell layers of the glands. Subsequently, the sugars detected on the salivary gland surface were employed to investigate the interaction between Trypanosoma rangeli and the R. prolixus salivary glands. In vitro adhesion inhibition assays using long epimastigote forms (the invasion/adhesion forms) showed that some sugars tested were able to block the receptors on both the surfaces of the salivary glands and on T. rangeli. Among the sugars tested, GlcNAc, GalNAc, and galactose showed the highest overall inhibitory effect, following pre-incubation of either the salivary glands or parasites. These results are discussed in relation to previous work on the role of carbohydrates and lectins in insect vector/parasite interactions.