CD43 (leukosialin, sialophorin, large sialoglycoprotein) can be expressed in both normal and Wiskott-Aldrich fibroblasts via transfection of a leukosialin cDNA.

Human leukosialin is among the most abundant sialoglycoproteins found on the surface of cells of the lympho-hematopoietic system. Leukosialin, also known as sialophorin, is involved in T cell proliferation, and its molecular isoform changes upon cellular activation. We show that human leukosialin is identical to the antigens described by the monoclonal antibodies (mAb) G10-2, G19-1 (CD43) and B1B6 (large sialoglycoprotein). This identity was suggested by immunoblot analysis of transformed cell lysates. Further, fibroblasts transfected with the human leukosialin cDNA gain reactivity to these mAb, showing conclusively that molecules recognized by these mAb are determined by the same cDNA. Expression of the leukosialin gene is readily detected on the surface of transfected human and mouse fibroblasts. Immunoblot analysis of the transfectants indicates that processing of the human protein occurs in both species. Alterations of leukosialin expression have been reported in patients with the Wiskott-Aldrich Syndrome (WAS), an X-chromosome-linked immunodeficiency disease. While essentially all of the transfected tumor and primary fibroblasts from normal individuals express the transfected gene on the cell surface, only half of the transfected Wiskott-Aldrich fibroblasts express CD43. Nonetheless, the antigenic pattern by immunoblot analysis of both normal and WAS-transfected fibroblasts appears identical. These results indicate that WAS-derived cells can express leukosialin and that the product of WAS X-chromosome mutation may not be expressed in fibroblasts.