HIV is adept at avoiding naturally generated T cell responses; therefore, there is a need to develop HIV-specific T cells with greater potency for use in HIV cure strategies. Starting with a CD4-based chimeric antigen receptor (CAR) that was previously used without toxicity in clinical trials, we optimized the vector backbone, promoter, HIV targeting moiety, and transmembrane and signaling domains to determine which components augmented the ability of T cells to control HIV replication. This re-engineered CAR was at least 50-fold more potent in vitro at controlling HIV replication than the original CD4 CAR, or a TCR-based approach, and substantially better than broadly neutralizing antibody-based CARs. A humanized mouse model of HIV infection demonstrated that T cells expressing optimized CARs were superior at expanding in response to antigen, protecting CD4 T cells from infection, and reducing viral loads compared to T cells expressing the original, clinical trial CAR. Moreover, in a humanized mouse model of HIV treatment, CD4 CAR T cells containing the 4-1BB costimulatory domain controlled HIV spread after ART removal better than analogous CAR T cells containing the CD28 costimulatory domain. Together, these data indicate that potent HIV-specific T cells can be generated using improved CAR design and that CAR T cells could be important components of an HIV cure strategy.

Chimeric antigen receptors (CARs) have shown remarkable ability to re-direct T cells to target CD19-expressing tumours, resulting in remission rates of up to 90% in individuals with paediatric acute lymphoblastic lymphoma. Lessons learned from these clinical trials of adoptive T cell therapy for cancer, as well as investments made in manufacturing T cells at commercial scale, have inspired researchers to develop CARs for additional applications. Here, we explore the challenges and opportunities of using this technology to target infectious diseases such as with HIV and undesired immune responses such as autoimmunity and transplant rejection. Despite substantial obstacles, the potential of CAR T cells to enable cures for a wide array of disease settings could be transformational for the medical field.

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Lymphocyte migration is essential for adaptive immune surveillance. However, our current understanding of this process is rudimentary, because most human studies to date have been restricted to immunological analyses of blood and various tissues.We used an integrated approach to characterize tissue-emigrant immune cells in thoracic duct lymph (TDL). The prevalent immunocytes in human and non-human primate efferent lymph were T cells. Cytolytic CD8 + T cell subsets with effector-like epigenetic and transcriptional signatures were clonotypically discrete and selectively confined to the intravascular circulation, whereas non-cytolytic CD8 + T cell subsets with stem-like epigenetic and transcriptional signatures predominated in tissues and TDL. Moreover, these anatomically distinct gene expression profiles were recapitulated at the level of individual clonotypes, suggesting parallel differentiation programs independent of the expressed antigen receptor. Our collective dataset provides an atlas of the migratory immune system and defines the nature of tissueemigrant CD8 + T cells that recirculate via TDL.

BACKGROUND. We performed a Phase I clinical trial that infused CCR5 gene edited CD4 T cells to determine how these T cells can better enable HIV cure strategies. METHODS. The trial addressed the method of zinc finger nuclease (ZFN) ex vivo delivery, whether CCR5 Δ32 heterozygotes preferentially benefit, the effect of CCR5 gene edited CD4 T cells on the HIV-specific T cell response, and the ability of infused CCR5 gene edited T cells to delay viral rebound during analytical treatment interruption. We enrolled 14 people living with HIV whose viral load was well controlled by antiretroviral therapy (ART). We measured time to viral rebound after ART withdrawal, persistence of CCR5-edited CD4 T cells, and whether infusion of 10 billion CCR5-edited CD4 T cells augmented the HIV-specific immune response. RESULTS. Infusion of the CD4 T cells was well tolerated with no serious adverse events. Modest delay to the time of viral rebound was observed relative to historical controls; however, three of 14 individuals of which two were CCR5 Δ32 heterozygotes appeared to regain control of viremia before ultimately rebounding. Interestingly, only these individuals had substantial restoration of HIV-specific CD8 T cell responses. Immune escape to one of these re-invigorated responses was observed at viral recrudescence, illustrating a direct link between viral control and enhanced CD8 T cell responses. CONCLUSION. These findings demonstrate how CCR5 gene edited CD4 T cell infusion could aid HIV cure strategies by augmenting pre-existing HIV-specific immune responses.