Identification of CD66a and CD66b as the major galectin-3 receptor candidates in human neutrophils

The mammalian lectin galectin-3 is a potent stimulus of human neutrophils, provided that the receptor(s) for the lectin has been mobilized to the cell surface before activation, We have recently shown that the receptors for g alectin-3 are stored in intracellular mobilizable granules. Here we show su pportive evidence for this in that DMSO-differentiated (neutrophil-like) HL -60 cells, which lack gelatinase and specific granules, are nonresponsive w hen exposed to galectin-3. Neutrophil granules were subsequently used for i solation of galectin-3 receptors by affinity chromatography, Proteins elute d from a galectin-3-Sepharose column by lactose were analyzed on SDS-polyac rylamide gels and showed two major bands of 100 and 160 kDa and a minor ban d of 120 kDa, By immunoblotting, these proteins were shown to correspond to CD66a (160 kDa), CD66b (100 kDa), and lysosome-associated membrane glycopr otein-1 and -2 (Lamp-1 and -2; 120 kDa). The unresponsive HL-60 cells lacke d the CD66 Ags but contained the Lamps, implying that neutrophil CD66a and/ or CD66b may be the functional galectin-3 receptors, This conclusion wa sup ported by the subcellular localization of the CD66 proteins to the gelatina se and specific granules in resting neutrophils.