Fractalkine produced by Shiga toxin type 2-stimulated human glomerular endothelial cells modulates γδ T lymphocyte migration

Introduction γδ T cells play a critical role in tissue immunosurveillance through their capacity to sense cellular stress. However, their recruitment dynamics to peripheral organs such as kidney during Shiga toxin (Stx)–induced renal damage, remain undefined. Since the CX 3 CL1/CX 3 CR1 axis is vital for leukocyte homing into inflamed organs, we investigated its participation in mediating γδ T cell trafficking to the Stx–damaged kidney. Material We integrated in vitro functional assays using Stx2a-stimulated human glomerular endothelial cells (HGEC) with in silico single-cell RNA sequencing (scRNA–seq) analysis of public human kidney injury datasets. CX 3 CL1/CX 3 CR1 expression was evaluated via qPCR, ELISA, and flow cytometry, while the functional recruitment γδ T cells recruitment was quantified using transwell migration assays. Results In vitro , Stx2a significantly upregulates CX3CL1 mRNA and protein secretion in HGEC. In silico profiling of acute kidney injury (AKI) tissues confirmed widespread CX3CL1 upregulation in the damaged parenchyma and identified a distinct TRGV9 + cell cluster expressing CX3CR1 transcripts. Contingency analysis showed that TRGV9 + cells were substantially more likely to express CX3CR1 than other T/NKT cells. Importantly, flow cytometry analysis confirmed that γδ T cells express high levels of CX 3 CR1 protein. Finally, transwell assays demonstrated that both Stx2a-conditioned HGEC media and recombinant CX 3 CL1 potently induce γδ T cell migration, an effect that was completely abrogated upon disruption of the chemokine gradient. Discussion Together, these findings suggest that CX 3 CL1 release by Stx2a-stimulated endothelial cells contributes to a chemotactic gradient that may mediate the targeted recruitment of circulating CX3CR1 + TRGV9/TRDV2 cells to the injured kidney.