Characterization of CAR T cell expansion and cytotoxic potential during Ex Vivo manufacturing using image-based cytometry.

Since the FDA approval of two Chimeric Antigen Receptor (CAR) T cell therapies against CD19+ malignancies, there has been significant interest in adapting CAR technology to other diseases. As such, the ability to simultaneously monitor manufacturing criteria and functional characteristics of multiple CAR T cell products by a single instrument would likely accelerate the development of candidate therapies. Here, we demonstrate that image-based cytometry yields high-throughput measurements of CAR T cell proliferation and size, and captures the kinetics of in vitro antigen-specific CAR T cell-mediated killing. The data acquired and analyzed by the image cytometer are congruent with results derived from conventional technologies when tested contemporaneously. Moreover, the use of bright-field and fluorescence microscopy by the image cytometer provides kinetic measurements and rapid data acquisition, which are direct advantages over industry standard instruments. Together, image cytometry enables fast, reproducible measurements of CAR T cell manufacturing criteria and effector function, which can greatly facilitate the evaluation of novel CARs with therapeutic potential.

HIV-Resistant and HIV-Specific CAR-Modified CD4+ T Cells Mitigate HIV Disease Progression and Confer CD4+ T Cell Help In Vivo.

HIV infection preferentially depletes HIV-specific CD4+ T cells, thereby impairing antiviral immunity. In this study, we explored the therapeutic utility of adoptively transferred CD4+ T cells expressing an HIV-specific chimeric antigen receptor (CAR4) to restore CD4+ T cell function to the global HIV-specific immune response. We demonstrated that CAR4 T cells directly suppressed in vitro HIV replication and eliminated virus-infected cells. Notably, CAR4 T cells containing intracellular domains (ICDs) derived from the CD28 receptor family (ICOS and CD28) exhibited superior effector functions compared to the tumor necrosis factor receptor (TNFR) family ICDs (CD27, OX40, and 4-1BB). However, despite demonstrating limited in vitro efficacy, only HIV-resistant CAR4 T cells expressing the 4-1BBζ ICD exhibited profound expansion, concomitant with reduced rebound viremia after antiretroviral therapy (ART) cessation and protection of CD4+ T cells (CAR-) from HIV-induced depletion in humanized mice. Moreover, CAR4 T cells enhanced the in vivo persistence and efficacy of HIV-specific CAR-modified CD8+ T cells expressing the CD28ζ ICD, which alone exhibited poor survival. Collectively, these studies demonstrate that HIV-resistant CAR4 T cells can directly control HIV replication and augment the virus-specific CD8+ T cell response, highlighting the therapeutic potential of engineered CD4+ T cells to engender a functional HIV cure.