Hematopoietic stem/progenitor cells engineered with T cell receptors for immunotherapy for HIV infection

Abstract

HIV infection causes progressive depletion of CD4+ T cells and leads to severe immunodeficiency if left untreated. Current antiretroviral therapy can control infection, but does not cure it. The goal of this study was to develop a “functional cure” for HIV infection by providing a long-term, self-renewing source of antiviral immunity. To that end, we hypothesized that immunotherapy using engineered hematopoietic stem/progenitor cells (HSPCs) to express HIV-specific T cell receptors (TCRs) will be effective at controlling HIV. We first isolated six TCRs specific to the KK10 epitope from HLA-B27+ individuals and compared their function in vitro. Two TCRs, EC27 and EC5.5, were chosen for immunotherapy studies based on their superior function. To test HSPC-based immunotherapy, we transduced mobilized peripheral blood CD34+ HSPCs from HLA-B27+ healthy donors to express these TCRs and engrafted them in immunocompromised NOD/SCID/IL2Rγc^−/− (NSG) mice. Transduced HSPCs were able to engraft mice and differentiate into T cells expressing the TCRs in peripheral blood and lymphoid tissues. Furthermore, engineered T cells isolated from engrafted mice showed KK10-driven expansion, cytotoxicity, and cytokine secretion. Expanded T cells were able to inhibit HIV-infection in vitro. Moreover, the functional activity of engineered T cells isolated from mice was comparable to modified primary T cells, highlighting their therapeutic potential. We are currently testing whether mice engrafted with transduced HSPCs can suppress HIV infection in vivo. If successful, these studies would demonstrate a “functional cure” of HIV infection, warranting further testing in clinical trials.