Supraphysiologic control over HIV-1 replication mediated by CD8 T cells expressing a re-engineered CD4-based chimeric antigen receptor

Abstract

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.

Adult and Cord Blood-Derived High-Affinity gB-CAR-T Cells Effectively React Against Human Cytomegalovirus Infections

“…Taken as a whole, CAR-T cell technologies as antiviral therapies are continuously evolving in regard to optimization of scFvs, signaling designs, and stability of expression of the CAR transgene. [45][46][47] Here, engineering of CAR-T cells with an scFv design based on a high-affinity neutralizing anti-gB antibody fused to 4-1BB showed conclusive results for the control of HCMV infection in vitro and encouraging results in vivo. A therapeutic variability could be expected and still remains to be minimized by new CAR delivery approaches, such as by gene editing to abrogate the TCR signaling.…”

Membrane-proximal external region is a superior target for mediating effector activity of HIV-1 specific chimeric antigen receptor modified T cells

“…In recent years, CAR technology has been extensively expanded as an HIV-1 curative therapy [13, 15, 16, 26, 27, 47, 61-63]. Various anti-HIV-1 CARs targeting multiple different epitopes have been designed and evaluated their effector activities in in vitro and in vivo systems (See review[47]).…”

Advances in Developing CAR T-Cell Therapy for HIV Cure

“…Beside the above-mentioned advantages and potential problems of CAR T therapy, there are some other important developments in HIV CAR T strategies, including improvements of CAR T in tumor therapy that might be useful for HIV cure. Leibman et al optimized the construction of CD4 receptor-based CAR from the lessons of engineering CARs for hematologic malignancies (128). In terms of capacity to control HIV replication, their re-engineered CAR was at least 50-fold more effective than the original CD4 receptor-based CAR, a TCR-based approach, and bNAb-based CARs.…”