EBV-transformed B-cells from an individual homozygously mutated (G329A) in FUT7 do not roll on E-selectin

• The α1,3 fucosyltransferase VII (Fuc-TVII) is involved in the biosynthesis of E- and P-selectin ligands such as sialyl Lewis x on human leukocytes. Recently, individuals were characterized carrying a missense mutation (G329A; Arg110-Gln) in the FUT7 gene encoding this enzyme. The mutated FUT7 construct was not able to produce an active Fuc-TVII enzyme in transfection studies and polymorphonuclear granulocytes from an individual carrying the mutation homozygously showed severely reduced expression of sialyl Lewis x. In the present study we have established Epstein-Barr virus transformed B-celllines from this individual (SIGN) and from an individual not carrying the mutation (IWO). The cell lines were confirmed to be of B-cell origin by flow cytometry analysis. IWO cells interacted with E-selectin in an in vitro flow chamber analysis whereas SIGN cell did not. However, when SIGN cell were transfected with wild type FUT7 cDNA interaction with E-selectin could be restored. Cell surface expression of the sLex related epitopes recognized by antibodies CSLEX-1, KM-93 and HECA-452 was elevated on IWO cells compared to SIGN cells, consistent with a role of these antigens in E-selectin recognition. Despite high expression of PSGL-1 neither of the cell lines interacted with P-selectin under flow. These cell lines may be useful in the further characterization ofEselectin ligands and the obtained results encourage further studies on the consequences of the FUT7-G329A mutation in vivo.

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