以 PD1-TIGIT 嵌合免疫检查点转换受体增强 T 细胞抗肿瘤疗效

Chimeric antigen receptor (CAR) T cell immunotherapy has demonstrated success in the treatment of hematological malignancies; however, its efficacy and applications in solid tumors remain limited. Immunosuppressive factors, particularly inhibitory checkpoint molecules, restrict CAR T cell activity inside solid tumors.

The modulation of checkpoint pathways has emerged as a promising approach to promote anti-tumor responses in CAR T cells. Programmed cell death protein 1 (PD1) and T cell immunoreceptor with Ig and ITIM domains (TIGIT) are two critical immune-checkpoint molecules that suppress anti-tumor activity in T cells. Simultaneous targeting of these two inhibitory molecules could be an efficient checkpoint modulation strategy.

Here, we developed a PD1-TIGIT chimeric immune-checkpoint switch receptor (CISR) that enhances the efficacy of CAR T cell immunotherapy by reversing the inhibitory checkpoint signals of PD1/PDL1 and/or TIGIT/CD155.

In addition to neutralizing PDL1 and CD155, this chimeric receptor is engineered with the transmembrane region and intracellular domain of CD28, thereby effectively enhancing T cell survival and tumor-targeting functions.

Notably, under simultaneous stimulation of PDL1 and CD155, CISR-CAR T cells demonstrate superior performance in terms of cell survival, proliferation, cytokine release, and cytotoxicity in vitro , compared with conventional CAR T cells. Experiments utilizing both cell line- and patient-derived xenotransplantation tumor models showed that CISR-CAR T cells exhibit robust infiltration and anti-tumor efficiency in vivo .

Our results highlight the potential for the CISR strategy to enhance T cell anti-tumor efficacy and provide an alternative approach for T cell-based immunotherapies.