Human immunodeficiency virus type 1 restriction by human-rhesus chimeric tripartite motif 5α (TRIM 5α) in CD34+ cell-derived macrophages in vitro and in T cells in vivo in severe combined immunodeficient (SCID-hu) mice transplanted with human fetal tissue

Species-specific innate resistance against viral infections offers novel avenues for antiviral therapeutics. The retroviral restriction factor TRIM5 alpha ( tripartite motif 5 alpha protein) has been shown to potently restrict human immunodeficiency virus (HIV)-1 infection in otherwise susceptible cell lines and CD34(+) cell- derived macrophages. A 13-amino acid patch in the C-terminal B30.2 ( SPRY) domain of rhesus macaque TRIM5 alpha has been shown to be involved in HIV-1 capsid recognition and is critical for viral inhibition. A chimeric human - rhesus TRIM5 alpha ( TRIM5 alpha-HRH) was generated by replacing an 11-amino acid patch in the human isoform with the rhesus 13-amino acid patch. Here we show that lentiviral vector expression of this human - rhesus chimera in HIV-1-permissive MAGI-CXCR4 cells conferred resistance as well as a selective survival advantage on HIV-1 challenge. To apply these findings in a stem cell gene therapy setting, TRIM5 alpha-HRH was expressed in CD34(+) cell-derived macrophages in vitro and in SCID-hu mouse-derived thymocytes in vivo. On viral challenge, transgenic macrophages and thymocytes were highly resistant to HIV-1 compared with control cells. Normal development of TRIM5 alpha-HRH-expressing macrophages and in vivo-derived T cells was also observed by phenotypic flow cytometric analysis. These results demonstrate the efficacy of TRIM5 alpha-HRH in a stem cell setting and its further advancement for use in gene therapy applications.