Regulatory TCRαβ⁺ Double Negative T Cells Suppress γδ T Cells and Alleviate Colitis

Inflammatory bowel disease arises from dysregulated immune activations triggered by a myriad of factors. The maintenance of immune tolerance within the intestinal milieu and the suppression of inflammatory responses remain the most efficacious strategies for alleviating enteritis. Regulatory TCRαβ⁺ double-negative T (DNT) cells play pivotal roles in orchestrating the homeostasis of various organs; however, their specific influence on colitis has yet to be thoroughly elucidated.

Single-cell RNA sequencing and adoptive transfer were used to delineate the distinct signatures of DNT cells and to investigate their role in the context of colitis, respectively.

Our observations revealed that the proportions of DNT cells within the CD3⁺TCRβ⁺NK1.1^- populations in the naive murine colonic lamina propria and intraepithelial layer were significantly elevated compared with those in the mesenteric lymph node, with further augmentation noted in the colon of colitis mice. The adoptive transfer of DNT cells conferred relief from colitis symptoms. E-cadherin facilitated the interaction between DNT cells and CD103⁺ γδ T cells, thereby collaboratively enhancing the cytotoxicity of DNT cells against γδ T-cell populations in concert with NKG2D, ultimately promoting the remission of colitis. Furthermore, mice that received allogeneic DNT cells exhibited ameliorated colitis without inducing graft-versus-host disease.

Among the diverse populations of DNT subsets, regulatory DNT cells are capable of accumulating in the inflamed colon, thereby preventing the progression of colitis through the suppression of CD103⁺ γδ T-cell responses. The adoptive transfer of DNT cells could be a novel therapeutic strategy for inflammatory bowel disease.