Distinct binding patterns of fucose-specific lectins from Biomphalaria alexandrina and Lotus tetragonolobus to murine lymphocyte subsets

The putative expression of distinct terminally fucosylated glycoconjugates among murine lymphocyte subpopulations was sought using a Biomphalaria alexandrina-derived lectin (BaSI), of proven specificity to a fucosyllactose determinant, and the fucose-binding lectin from Lotus tetragonolobus seeds. Direct labeling of isolated lymphocyte subsets in suspension as well as immuno-histochemical and two-dimensional Western blotting assays demonstrated the exclusive expression of the BaSI-reactive ligand among multiple isoforms of two major 95 and 92 kDa and a minor 82 kDa acidic glycoproteins, selectively localized to the splenic marginal zone B lymphocytes of adult mice. The expression of the L. tetragonolobus lectin-reactive ligand was, on the other hand, restricted primarily to a single homogeneous 50 kDa acidic glycoprotein associated with a subset of the mature (PNA(-)) medullary thymocytes of adult mice as well as a minority of the immature (PNA(+)) thymocytes within the deep cortical region in newly born mice. The significance of these findings is discussed in relation to mechanisms that govern lymphocyte development and homing. (C) 2005 Elsevier GmbH. All rights reserved.