Lentiviral and murine retroviral transduction of T cells for expression ofhuman CD40 ligand

Efficient transduction of primary human T cells is an important goal toward treating a number of genetic defects. Patient T cells could be harvested b y leukapheresis, transduced, and returned to the donor. A wide range of sec reted or cell surface therapeutic proteins may be delivered in this way. Th e ability to produce antibodies is the consequence of interactions between T cells and B cells and lack of expression of CD40 ligand (CD40L) on T cell s causes X-linked hyper-IgM syndrome (XHIM). We are investigating delivery of a normal CD40 ligand to treat this disorder, We tested promoters driving the expression of either reporter genes such as enhanced green fluorescent protein (eGFP) or human CDC40L. Using murine retroviruses, the best able t o drive gene expression in T cells was the cytomegalovirus (CMV) promoter e nhancer element; however, transduction efficiency was low. To achieve effic ient, high-level gene expression we tested lentiviral gene delivery vectors . At a low multiplicity of infection (MOI) (0.5-2) a large fraction of targ et cells was transduced by lentiviral vectors (40-93%), and the strength of gene expression was high, as determined by flow cytometric analysis. We mo nitored the expression of eGFP or human CD40L on T cell lines and untransfo rmed primary human T cells from normal and CD40L-deficient patients. We ach ieved efficient gene expression without an extended exposure to virus, and without the need for selection. These results are encouraging for efficient lentivirus-mediated transduction of refractory human cells to achieve ther apeutic gene delivery.