Neutrophil NCA-160 (CD66) Is the Major Protein Carrier of Selectin Binding Carbohydrate Groups Lewisx and Sialyl Lewisx

The neutrophil surface carbohydrate groups Lewisx and sialyl Lewisx have previously been shown to interact with the vascular selectins E- and P-selectin. However, the proteins expressing these carbohydrate groups have not been fully characterised. We show that these carbohydrate groups, and the structurally related Lewisa group, are all carried predominantly on a sub-population of the carcinoembryonic antigen (CEA) related NCA-160, which is also recognised by CD66 antibodies. We demonstrate that the related NCA-160, NCA-90/95 and CD67 all undergo an increase in surface expression in response to fMLP stimulation, and that this increase is greater than that observed for the sialyl and non-sialyl Lewisx carbohydrate groups. These data suggest that the expression of differently glycosylated forms of NCA is independently regulated.