Single-cell RNA sequencing reveals the molecular features of peripheral blood immune cells in children, adults and centenarians

The molecular and functional characteristics of peripheral blood immune cells in childhood may contribute to the specialized immune system in children. At present, few researches have compared immune cells in childhood with other age groups, and there is a lack of understanding of immune cells in childhood from the whole lifespan. To display the molecular characteristics of peripheral blood immune cells in childhood at the single-cell level, we performed a comparative study by constructing a peripheral blood mononuclear cell (PBMC) atlas of multiple age groups, including children, young adults, middle-aged adults, aged adults and supercentenarians. The atlas revealed that monocytes in childhood were markedly different from those in other periods. B cells in childhood had a greater ability to respond to viruses and to activate mast cells. Remarkably, we identified a new subtype of CD8+ cytotoxic T cells expressing both naïve and cytotoxicity genes specifically in childhood. The marker genes of this subtypes were used as marker proteins for flow cytometry analysis, and the results confirmed the findings of the scRNA-seq. Moreover, there was more frequent crosstalk between PBMCs in childhood than in other periods, which may be one of the characteristics of the immune system in childhood. Finally, the differences in the expression of susceptibility genes in the PBMCs of different age groups may indicate differences in the disease spectrum of different age groups. In conclusion, this research systematically described the molecular characteristics of peripheral blood immune cells in childhood from multiple levels, and provided new evidence to elucidate the special immune environment of childhood. PBMCs from healthy children controls were subjected to scRNA-seq with 10x Genomics. >>>Raw data are not available due to patient privacy concerns<<<