Cell surface carbohydrate of Leishmania mexicana amazonensis: differences between infective and non-infective forms

The cell surface carbohydrates of Leishmania mexicana amazonensis (amastigotes and promastigotes, both infective and non-infective forms) were comparatively analyzed by agglutination assay employing 28 highly purified lectins, and by binding assay using 125I-labeled lectins. Among the D-GalNAc binding lectins, Bandeiraea simplicifolia-I, Dolichos biflorus, Phaseolus vulgaris and Glycine max were highly specific for the amastigotes, while that from Maclura aurantiaca selectively agglutinated promastigotes. The lectins from Wistaria floribunda, Phaseolus lunatus (D-GalNAc), Arachis hypogaea (D-Gal) and Triticum vulgaris (D-GlcNAc) were selective for the infective forms (both amastigotes and promastigotes), not reacting with the non-infective ones. Conversely, no parasite agglutination occurred with the L-fucose binding lectins Lotus tetragonolobus and Ulex europaeus-I. Binding studies with 125I-labeled lectins from Wistaria floribunda, Triticum vulgaris and Arachis hypogaea were performed to find whether unagglutinated non-infective promastigotes might have receptors for these lectins, in which case absence of agglutination could be due to a peculiar arrangement of the receptors. These assays essentially confirmed the selectivity, demonstrated in the agglutination assays of these lectins for the infective promastigotes.