Retrovirus‐mediated transfer of the herpes simplex virus thymidine kinase and enhanced green fluorescence protein genes in primary T lymphocytes

The EGFP‐tk retroviral vector, encoding enhanced green fluorescent protein (EGFP) and the herpes simplex virus thymidine kinase (HSV‐tk) packaged in a Phoenix amphotropic cell line, was used to transduce healthy donor T lymphocytes. Infection yielded a mean of 41·8 ± 9·3% SD (range 31·1–48·4%) EGFP‐positive cells and a mean of 92 ± 2% SD (range 90–94%) after cell sorting. EGFP expression remained stable for 30 d after infection. The entire gene transfer procedure had no significant effect on lymphocyte subsets and slightly reduced clonogenicity. Ganciclovir (gcv) treatment (1 µg/ml × 10 d) killed all EGFP‐positive cells in the transduced and transduced/sorted populations, but had no effect on untransduced controls. Our results show that primary T lymphocytes can be transduced using an EGFP‐tk vector that yields a homogeneous infected population without affecting lymphocyte subsets, function and clonogenicity.