Glioblastoma-targeted CD4+ CAR T cells mediate superior antitumor activity

Abstract

Chimeric antigen receptor-modified (CAR-modified) T cells have shown promising therapeutic effects for hematological malignancies, yet limited and inconsistent efficacy against solid tumors. The refinement of CAR therapy requires an understanding of the optimal characteristics of the cellular products, including the appropriate composition of CD4+ and CD8+ subsets. Here, we investigated the differential antitumor effect of CD4+ and CD8+ CAR T cells targeting glioblastoma-associated (GBM-associated) antigen IL-13 receptor α2 (IL13Rα2). Upon stimulation with IL13Rα2+ GBM cells, the CD8+ CAR T cells exhibited robust short-term effector function but became rapidly exhausted. By comparison, the CD4+ CAR T cells persisted after tumor challenge and sustained their effector potency. Mixing with CD4+ CAR T cells failed to ameliorate the effector dysfunction of CD8+ CAR T cells, while surprisingly, CD4+ CAR T cell effector potency was impaired when coapplied with CD8+ T cells. In orthotopic GBM models, CD4+ outperformed CD8+ CAR T cells, especially for long-term antitumor response. Further, maintenance of the CD4+ subset was positively correlated with the recursive killing ability of CAR T cell products derived from GBM patients. These findings identify CD4+ CAR T cells as a highly potent and clinically important T cell subset for effective CAR therapy.

Harnessing neoantigen specific CD4 T cells for cancer immunotherapy

“…Thus, NeoAg‐reactive TCRm antibodies could be used with current CAR technology to provide specificity against NeoAgs in the near future. Surprisingly, recent mouse studies have highlighted that CD4 + CAR T cells alone mediate superior antitumor activity relative to their CD8 + counterparts 90–93 . Whereas the cytotoxic capacity of CD4 + T cells in tumor models is hardly novel, 80,94–96 in the context of CAR T therapy, CD4 + T cells also mediate tumor cytotoxicity directly, resist AICD, do not help CTLs resist exhaustion, and are in fact impeded by their CD8 + compatriots 90 .…”

“…Surprisingly, recent mouse studies have highlighted that CD4 + CAR T cells alone mediate superior antitumor activity relative to their CD8 + counterparts. [90][91][92][93] Whereas the cytotoxic capacity of CD4 + T cells in tumor models is hardly novel, 80,[94][95][96] in the context of CAR T therapy, CD4 + T cells also mediate tumor cytotoxicity directly, resist AICD, do not help CTLs resist exhaustion, and are in fact impeded by their CD8 + compatriots. 90 Future CAR trials should test whether enriched CD4 + T cells are similarly superior in humans as they are in mice.…”

Clinical chimeric antigen receptor‐T cell therapy: a new and promising treatment modality for glioblastoma

“…109 Improvements in activity and persistence of IL13Ra2-CAR-T cells have also been observed when the T cells were engineered to express transgenic IL-15 although antigen escape was more common. Surprisingly, delivery of a purified CD4 + population of IL-13Ra2-CAR-T cells resulted in enhanced antitumor activity and persistence compared to either purified CD8 + or mixed CD4 + /CD8 + populations.…”

“…Surprisingly, delivery of a purified CD4 + population of IL-13Ra2-CAR-T cells resulted in enhanced antitumor activity and persistence compared to either purified CD8 + or mixed CD4 + /CD8 + populations. 109 Improvements in activity and persistence of IL13Ra2-CAR-T cells have also been observed when the T cells were engineered to express transgenic IL-15 although antigen escape was more common. 110 And finally, NKG2D-based CAR-T cells displayed synergistically enhanced antitumor activity when the mice were also treated with radiation, an effect attributed not only to radiation-induced upregulation of NKG2D ligands, but also enhanced CAR-T cell trafficking into the tumor.…”

Chlorotoxin Redirects Chimeric Antigen Receptor T Cells for Specific and Effective Targeting of Glioblastoma

“…First, screening degranulation and cytokine-production against a panel of 10 PBT-TS lines, we observed that CLTX-EQ-28ζ CAR T cells displayed higher degranulation, but lower IFNγ production as compared to CLTX-CD8h-28ζ CAR T cells (Fig.S3, D and E). Next, the capacities of CLTX-EQ-28ζ and CLTX-CD8h28ζ CAR T cells to maintain long-term antitumor activity were evaluated in a repetitive tumor challenge assay (48). We observed that CLTX-EQ-28ζ, but not CLTX-CD8h-28ζ, CAR T cells retained activity through multiple rounds of tumor challenge ( Fig.…”