Lens Epithelium-derived Growth Factor/p75 Qualifies as a Target for HIV Gene Therapy in the NSG Mouse Model

Lens epithelium-derived growth factor (LEDGF/p75) is an essential cofactor of HIV integration. Both stable overexpression of the C-terminal part of LEDGF/p75 (LEDGF325–530) containing the integrase (IN)-binding domain (IBD) and stable knockdown (KD) of LEDGF/p75 are known to inhibit HIV infection in laboratory cell lines. Here, primary human CD4+ T-cells were transduced with lentiviral vectors encoding LEDGF325–530, the interaction-deficient mutant LEDGF325–530D366N, or a hairpin depleting LEDGF/p75 and challenged with HIV. Maximal protection of primary T-cells from HIV infection was obtained after LEDGF325–530 overexpression reducing HIV replication 40-fold without evidence of cellular toxicity. This strategy was subsequently evaluated in the NOD.Cg-PrkdcscidIl2rgtm1Wjl/SzJ (NSG) mouse model. Threefold reduction in mean plasma viral load was obtained in mice engrafted with CD4+ T-cells expressing LEDGF325–530 in comparison with engraftment with LEDGF325–530D366N cells. Four weeks after transplantation with LEDGF325–530D366N cells, 70% of the CD4+ cells were lost due to ongoing HIV replication. However, in mice transplanted with LEDGF325–530 cells only a 20% decrease in CD4+ cells was measured. Liver and spleen sections of LEDGF325–530 mice contained less HIV than LEDGF325–530D366N mice as measured by p24 antigen detection. LEDGF325–530 overexpression potently inhibits HIV replication in vivo and protects against HIV mediated cell killing of primary CD4+ T-cells.