αβγ8 T cells play a vital role in fetal human skin development and immunity

T cells in human skin play an important role in the immune defense against pathogens and tumors. T cells are present already in fetal skin, where little is known about their cellular phenotype and biological function. Using single-cell analyses, we identified a naive T cell population expressing ?? and ?8 T cell receptors (TCRs) that was enriched in fetal skin and intestine but not detected in other fetal organs and peripheral blood. TCR sequencing data revealed that double-positive (DP) ???8 T cells displayed little overlap of CDR3 sequences with single-positive ?? T cells. Gene signatures, cytokine profiles and in silico receptor?ligand interaction studies indicate their contribution to early skin development. DP ???8 T cells were phosphoantigen responsive, suggesting their participation in the protection of the fetus against pathogens in intrauterine infections. Together, our analyses unveil a unique cutaneous T cell type within the native skin microenvironment and point to fundamental differences in the immune surveillance between fetal and adult human skin.

Automated summary

Single-cell analyses identified a naive T cell population expressing specific T cell receptors enriched in fetal skin and intestine. These cells may contribute to early skin development and fetal immune defense, showing fundamental differences in immune surveillance between fetal and adult human skin.