Neuroprotective role of DNTαβ Cell transplantation on modulating immune microenvironment in spinal cord injured mice.

Traumatic spinal cord injury (SCI) is a common disabling condition characterized by a disrupted immune microenvironment that significantly hinders neural regeneration. In recent years, CD3⁺CD4^-CD8^- double-negative T cells (DNT cells) have garnered considerable attention due to their multifaceted roles in immune regulation. Flow cytometry data indicate a significant increase in the proportion of DNT cells following SCI. Single-cell sequencing further demonstrates the heterogeneity of DNT cells, with CD3⁺TCRαβ⁺CD4^-CD8^-NK1.1^- T cells (DNTαβ) potentially playing an immune regulatory role. Accordingly, we hypothesize that the transplantation of DNTαβ cells could improve the immune microenvironment in the spinal cord. To test this hypothesis, we obtained DNTαβ cells for SCI treatment through flow cytometric sorting. Behavioral assessments indicated that both in situ injection and tail vein injection of DNTαβ cells significantly promoted the recovery of motor function in mice with SCI. Immunohistochemical analysis further revealed that DNTαβ cells can inhibit glial proliferation and promote neuronal survival and myelination. Transcriptomic sequencing data also supported the role of DNTαβ cell transplantation in modulating immune responses through the Gzmb and IFN pathways, to promote early repair and neuroprotection following SCI. Our findings suggest that exogenous supplementation of DNTαβ cells can regulate the immune microenvironment to enhance neural regeneration after SCI, providing new therapeutic strategies and data support for cellular therapies following SCI.