1. ¹Division of Hematology, Department of Internal Medicine, University Hospitals, 1211 Geneva-14, Switzerland
2. ²Department of Genetics and Microbiology, University Hospitals, 1211 Geneva-14, Switzerland
3. ³Department of Biochemistry, University of Lausanne, 1066 Epalinges, Switzerland

Correspondence: Rudolf H. Zubler, Fax: 41 22 372 72 88. E-mail: rudolf.zubler@hcuge.ch

Received 25 January 2005; Revised 13 April 2005; Accepted 2 May 2005.

Abstract

Recently, using HIV-1-derived lentivectors, we obtained efficient transduction of primary human B lymphocytes cocultured with murine EL-4 B5 thymoma cells, but not of isolated B cells activated by CD40 ligation. Coculture with a cell line is problematic for gene therapy applications or study of gene functions. We have now found that transduction of B cells in a system using CpG DNA was comparable to that in the EL-4 B5 system. A monocistronic vector with a CMV promoter gave 32 4.7% green fluorescent protein (GFP)⁺ cells. A bicistronic vector, encoding IL-4 and GFP in the first and second cistrons, respectively, gave 14.2 2.1% GFP⁺ cells and IL-4 secretion of 1.3 0.2 ng/10⁵ B cells/24 h. This was similar to results obtained in CD34⁺ cells using the elongation factor-1 promoter. Activated memory and naive B cells were transducible. After transduction with a bicistronic vector encoding a viral FLIP molecule, vFLIP was detectable by FACS or Western blot in GFP⁺, but not in GFP^-, B cells, and 57% of sorted GFP⁺ B cells were protected against Fas ligand-induced cell death. This system should be useful for gene function research in primary B cells and development of gene therapies.