Single-cell transcriptomic reference map of human peripheral blood γδ T cells from 1 year to 90 years reveals major changes before adulthood

Summary: γδ T cells have an unconventional biology as they develop as functional cells in the thymus, to thereafter adapt to postnatal cues and persist into adulthood in peripheral blood. Single-cell transcriptomics enables investigation of underlying molecular programs of γδ T cell effector functions in health and disease. However, the effect of age is often underestimated, and control transcriptome datasets of young healthy individuals are rare. Here, we generate a cost-effective single-cell transcriptomic reference of peripheral blood γδ T cells (106,711 cells) from 223 individuals from 1 year to 90 years, with improved coverage of infancy, childhood, and adolescence. Our analysis reveals that the most pronounced compositional and transcriptional changes of γδ T cells occur before adulthood, followed by relative stabilization of major states across adulthood. Together, our study provides a resource of single-cell transcriptomes of healthy individuals to investigate human γδ T cells in various diseases in future studies.