MazF is an Escherichia coli-derived endoribonuclease that selectively cleaves ACA sequences of mRNA prevalent in HIV. We administered a single infusion of autologous CD4 T lymphocytes modified to express a Tat-dependent MazF transgene to 10 HIV-infected individuals (six remaining on antiretroviral therapy [ART]; four undergoing treatment interruption post-infusion) in order to provide a population of HIV-resistant immune cells. In participants who remained on ART, increases in CD4 and CD8 T cell counts of ~200 cells/mm3 each occurred within 2 weeks of infusion and persisted for at least 6 months. Modified cells were detectable for several months in the blood and trafficked to gastrointestinal lymph tissue. HIV-1 Tat introduced ex vivo to the modified CD4+ T cells induced MazF expression in both pre- and post-infusion samples, and MazF expression was detected in vivo post-viral-rebound during ATI. One participant experienced mild cytokine release syndrome. In sum, this study of a single infusion of MazF-modified CD4 T lymphocytes demonstrated safety of these cells, distribution to lymph tissue and maintenance of Tat-inducible MazF endoribonuclease activity, as well as sustained elevation of blood CD4 and CD8 T cell counts. Future studies to assess effects on viremia and latent proviral reservoir are warranted.
Keywords: CD4 T lymphocyte; HIV infection; MazF endoribonuclease; gene therapy; immune therapy; tat-induced transgene.
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