Chimeric antigen receptor–T cells with cytokine neutralizing capacity

Abstract

Infusion of T lymphocytes expressing chimeric antigen receptors (CARs) can produce extraordinary antitumor activity in patients with leukemia, lymphoma, and myeloma. The signaling mechanisms activating T cells and provoking tumor cell killing also trigger cytokine secretion and macrophage activation, leading to cytokine release syndrome (CRS). CRS is a serious side effect of CAR–T cells, and proinflammatory interleukin-6 (IL-6) is central to its pathogenesis. To endow T cells with anti-CRS activity, we designed a nonsignaling membrane-bound IL-6 receptor (mbaIL6) constituted by a single chain variable fragment derived from an anti–IL-6 antibody linked to a transmembrane anchoring peptide. We found that mbaIL6 expressed on the surface of T cells could rapidly remove IL-6 from the culture supernatant. IL-6 removal was proportional to the number of mbaIL6+ cells, increased with T-cell proliferation, and neutralized IL-6 signaling and function. A construct encoding for mbaIL6 and an anti–CD19-41BB-CD3ζ CAR allowed simultaneous expression of both receptors. T cells with mbaIL6 and CAR neutralized macrophage-derived IL-6 while exerting powerful antitumor activity. Cytotoxicity and proliferation were identical to those of cells expressing CAR alone in vitro, and CAR–T cells were effective in xenograft models regardless of mbaIL6 expression. Levels of human IL-6 in mice, however, were greatly reduced if T cells expressed both receptors instead of CAR alone. Thus, CAR–T cells with on-board capacity to extinguish IL-6 represent a new approach to prevent CRS and suppress its severity without affecting the antitumor potential of CAR–T cells.

The Influence of Chimeric Antigen Receptor Structural Domains on Clinical Outcomes and Associated Toxicities

“…The choice of which specific costimulatory domain is more clinically effective though is not yet unanimous. Extensive work is underway to further improve upon these current second-generation CAR-T cell constructs by altering specific CAR domains including the hinge, TM and costimulatory domains, particularly for the treatment of more difficult immunosuppressive solid tumours [ 8 , 15 , 16 , 17 , 18 , 19 , 20 , 21 , 22 ].…”

Engineering cytokines and cytokine circuits

“…Engineering of cytokine consuming "sink" cells can also be a complementary powerful tool for sculpting cytokine milieus. A recent example of this nascent concept is engineered T cells constitutively expressing a nonsignaling membrane-bound IL-6R to effectively deplete IL-6 and thus reduce IL-6-mediated toxicity in mice (14). More controlled approaches are emerging in which modular sensing receptors, such as synNotch receptors (15), can be used to induce cytokine secretion or consumption in response to local disease or tissue antigen signals, yielding the potential of highly localized and programmable sink or source cells.…”

Preclinical development of CD126 CAR-T cells with broad antitumor activity

“…Interestingly, in our in vivo studies, we observed lower levels of SAA-3, the equivalent of human C-reactive protein and an important surrogate of CRS in human studies in mice treated with the CD126 targeting construct compared to controls. It has been suggested that IL-6-targeted CAR-T cells may be used to treat CRS 39 . It appears from our studies that CD126 targeting CAR-T cells may not only have broad antitumor activity but may be associated with a low risk of CRS, at least in the murine model.…”