Expression of ABH and X (Lex) antigens on platelets and lymphocytes.

We used a panel of reagents, polyclonal and monoclonal antibodies, and lectins to define the expression of the ABH- and Lewis-related specificities on platelets and lymphocytes. We also determined the expression of the alpha 2- and alpha 3-L-fucosyltransferases necessary for their biosynthesis. The antigens that could be detected by immunofluorescence and Western blot analysis were based on type 2 monofucosylated structures. Antibodies directed toward types 1, 3, and 4 ABH-, X- and Lewis-related antigenic determinants were always negative because the small amounts of ABH and Lewis antigens adsorbed from the serum could not be detected by these techniques. The presence of the type 2 ABH antigens on intrinsic glycoproteins was controlled by the H gene. This correlates with the presence of alpha 2-L-fucosyltransferase and the absence of alpha 3-L-fucosyltransferase on platelets. In contrast, ABH antigens were not detected by immunofluorescence on normal peripheral lymphocytes. These cells thus have only the small amounts of antigens adsorbed from the serum, these being under control of the secretor and Lewis genes. This correlates with the absence of alpha 2-L-fucosyltransferase on lymphocytes. When lymphocytes were transformed in vitro by the Epstein-Barr virus (EBV), however, they strongly expressed the X and sialylated X antigens, which are specific markers of normal granulocytes and monocytes, respectively. Treatment of EBV-transformed lymphoblastoid cell lines with 12-O-tetradecanoylphorbol-13-O-acetate significantly decreased the expression of X and sialylated X antigens along with that of surface immunoglobulins, whereas it induced a significant expression of the H antigen under control of the H gene.