Gene transfer into stimulated and unstimulated T lymphocytes by HIV-1-derived lentiviral vectors

Genetic modification of T lymphocytes holds great potential for treatments of cancer, T cell disorders and AIDS. While in the past recombinant murine retroviruses were the vectors of choice for gene delivery to T cells, vecto rs based on lentiviruses can provide additional benefits. Here, we show tha t VSV-G pseudotyped HIV 1 vector particles delivering the enhanced green fl uorescent protein (EGFP) efficiently transduce human T lymphocytes. Transdu ction efficiency was optimal when infection included centrifugation of cell s with concentrated vector supernatant in the presence of Polybrene. In con trast to previous reports describing murine retrovirus-mediated gene transf er to T lymphocytes, fibronectin did not improve the transduction efficienc y of the VSVG-pseudotyped HIV-1 particles. Similar gene transfer efficienci es were observed following stimulation of cells with PHA/IL-2 or anti-CD3i/ CD28i antibodies, although greater transgene expression was observed in the latter case. Interestingly, production of vectors in the absence of the ac cessory proteins Vif, Vpr, Vpu and Nef was accompanied by a 50% decrease in transduction efficiency in activated T cells. Transduction of T cells that were not stimulated before infection was achieved. No transduction of non- prestimulated cells was observed with a GALV-pseudotyped murine retroviral vector. The requirement for accessory proteins in non-prestimulated cells w as more pronounced. Our results have implications for lentiviral Vector tar geting of other cells of the hematopoietic system including stem cells.