Expression of human Wiskott-Aldrich syndrome protein in patients' cells leads to partial correction of a phenotypic abnormality of cell surface glycoproteins

The Wiskott-Aldrich syndrome (WAS) is an uncommon X-linked recessive diseas e characterized by thrombocytopenia, eczema and immunodeficiency. The bioch emical defect of this disorder primarily affects cells derived from bone ma rrow. To understand better the molecular mechanisms underlying this disease and to evaluate the possibility of correcting the genetic defects in hemat opoietic cells, a Moloney murine leukemia virus (MoMLV)- based retroviral v ector carrying a functional Wiskott-Aldrich syndrome protein (WASp) cDNA dr iven by an SV40 promoter (LNS-WASp) was constructed A packaging cell line c ontaining this vector produced a stable level of WAS protein and maintained a high titer of viral output. Epstein-Barr virus (EBV)transformed B lympho blastoid cell lines (B-LCL) from WAS patients, which lack expression of the WAS protein, were transduced by the LNS-WASp retroviral vector and showed expression of WASp by Western blot. Analysis of the O-gly-can pattern on ce ll surface glycoproteins from WAS patients' B-LCL showed an altered glycosy lation pattern, due to increased activity of beta-1, 6-N-acetylglucosaminyl transferase (C2GnT). Transduction by the retroviral vector carrying the fun ctional WASp cDNA partially restored the abnormal glycosylation pattern, an d was accompanied by a decreasing C2GnT activity. These findings imply a fu nctional linkage between the WAS protein and the expression of the glycosyl transferase involved in the O-glycosylation, and also suggest a potential g ene therapy via transferring a functional WASp cDNA into hematopoietic cell s for Wiskott-Aldrich syndrome.