A packaging cell line generating CD4-specific retroviral vectors for efficient gene transfer into primary human T-helper lymphocytes

Murine leukemia virus (MuLV) can be pseudotyped with a variant of the human immunodeficiency virus (HIV) envelope gene encoding the surface glycoprote in gp120-SU and a carboxy-terminally truncated transmembrane (TM) protein w ith only seven cytoplasmic amino acids. MuLV/HIV-1 pseudotyped retroviral v ectors selectively target gene transfer to human cells expressing both CD4 and CXCR4. To apply this vector system to gene therapy of human diseases, w e generated a stable packaging cell line, FLY-HIV-87, expressing the MuLV g ag and pol genes and the C-terminally truncated variant of the HIV-1 envelo pe gene, but no retroviral vector genome. Production of infectious vector p articles was tested after the introduction of different vector genomes and was in the range of 5 x 10(5) IU/ml. The vector particles could be concentr ated up to 25-fold. Specific and efficient gene transfer into CD4/CXCR4 exp ressing cell lines and stimulated primary human CD4+ peripheral blood lymph ocytes was achieved. Thus the packaging cell line FLY-HIV-87 is highly suit able for gene therapy of disorders of human T-helper cells.