AMARANTHUS LEUCOCARPUS LECTIN RECOGNIZES HUMAN NAIVE T-CELL SUBPOPULATIONS

Amaranthus leucocarpus lectin (ALL) is specific for GalNAc residue fou nd in the inner core of Gal beta 1,3GalNAc alpha 1,O-Ser/Thr disacchar ide (T-antigen) or GalNAc alpha 1,O-Ser/Thr (T-n-antigen). Flow cytome tric analysis using fluorescein-labeled lectin and monoclonal antibodi es against human cell surface markers indicated that 5.7% of mononucle ar cells from human healthy donors are recognized by ALL. These cells have the phenotype CD2(+)CD4(+)CD19(-) and most of the lymphocytes rec ognized are also CD27(+), CD45RA(+) and CD43(+). ALL possesses mitogen ic activity on lymphocytes after neuraminidase treatment. Our results indicate that the receptors recognized by ALL could be considered surf ace markers for naive human T lymphocyte subsets.