MLV-10A1 retrovirus pseudotype efficiently transduces primary human CD4+ T lymphocytes

Background: Previously, we showed that retroviral vectors pseudotyped with the envelope of the amphotropic murine leukemia virus 10A1 (MLV-10A1) more efficiently transduce primary human CD8+ T lymphocytes when compared with other A-MLV, gibbon ape leukemia virus (GaLV) and feline endogenous retrovirus (RD114) vector pseudotypes. For the success of several gene therapeutic approaches (ADA, HIV) it is important to effectively transduce primary human CD4+ T lymphocytes. Methods: We have used retroviral vectors encoding the enhanced green fluorescent protein (EGFP) as a marker gene and carrying envelopes of MLV-10A1, A-MLV and GaLV and have analyzed the transduction efficiency of both human CD4+ T cell lines (CEM, H9, HUT78, J16) and primary human CD4+ T lymphocytes using a RetroNectin-assisted transduction protocol and virus-containing supernatant. Results: In CD4+ T cell lines the MLV-10A1 vector pseudotype was most effective and infected up to 85% of cells which then stably expressed GFP over time. MLV-10A1 was also superior and infected approximately 32% of primary human CD4+ T lymphocytes in comparison to GaLV (18%) and A-MLV (12%). The superior efficiency of MLV-10A1 for the transduction of CD4+ T cells correlates with the longer half-life of this pseudotype in comparison to A-MLV and, as previously shown by interference analysis, with the usage of both the A-MLV (Pit2) and the GaLV receptor (Pit1) for cell entry. Conclusions: MLV-10A1 is a suitable vector for transferring genes with high efficacy into primary human CD4+ T lymphocytes. The use of MLV-10A1 pseudotyped vectors should make it easier to obtain a sufficient number of gene-modified T lymphocytes for an adoptive transfer.