Sangamo Therapeutics Inc. has reported preclinical results for IL23R-CAR-Tregs, a strategy based on chimeric antigen receptor (CAR)-modified regulatory T cells (Tregs) for the treatment of Crohn's disease (CD).

CD是一种自身免疫性炎症性肠病，会导致胃肠道慢性炎症，从而严重影响患者的生活。当前的治疗包括抗炎类固醇和靶向α4BETA7整合素和IL-12/IL-23的药物。

先前的调查表明,一个重要的角色for the IL-23/Th17/Treg axis in the pathogenesis of the disease. Regulatory T cells are a subset of immune cells with potent immunomodulatory functions, able to induce immune tolerance and restore homeostasis. CAR Tregs are expected to localize, activate, proliferate and exert their immunomodulatory action specifically at the disease site, overcoming the limitations of polyclonal Treg therapy.

Researchers confirmed that IL-23 receptor (IL23R) is overexpressed in the gut of CD patients as compared with controls. They have developed different allogenic IL23R-CAR-Tregs and evaluated different scFvs to select one with ability to bind IL23R, having the lowest background of activation and causing significant CAR-mediated activation. The selected IL23R-CAR-Treg candidate is a second-generation CAR composed of an anti-IL23R-scFv, fused in tandem with human CD8 linker, a transmembrane domain, CD28 intracellular costimulatory domain and human CD3zeta signaling domain. In vitro, Tregs transduced with the IL23R-CAR lead candidate were found to efficiently and significantly mediate suppressive activity through their CAR.

To test the strategy in vivo, an hmIL23R scFv was produced, able to recognize mouse IL23R, and was fused in tandem with mouse CD8 linker, mouse CD8 transmembrane domain, mouse CD28 intracellular costimulatory domain and mouse CD3zeta signaling domain to produce mouse IL23R-CAR-Tregs. These Tregs were assessed in a dextran sodium sulfate-IBD-C57BL/6 LYS.1 murine model. Three days after injection, IL23R-CAR-Tregs were found in the colon and mesenteric lymph nodes, and showed a significantly higher activation relative to the controls (P< 0.05 and < 0.001, respectively, in paired t-test).

Furthermore, cells were found to induce a higher reduction of the peak of the disease than in nontransduced mice or mice transduced with a nonfunctional CAR (P< 0.05). This reduction was maintained until sacrifice. Colon length was also increased in treated mice as compared with the other groups, indicating less inflammation. Altogether, the results confirm that the IL23R-CAR-Treg candidate is a potential therapeutic approach for the treatment of CD, and potentially other autoimmune disorders involving IL23R