Aging and variability among immune cells

Immunogenomics How and why the immune system becomes less effective with age are not well understood. Martinez-Jimenez et al. performed single-cell sequencing of CD4+ T cells in old and young mice of two species. In young mice, the gene expression program of early immune activation was tightly regulated and conserved between species. However, as mice aged, the expression of genes involved in pathways responding to immune cell stimulation was not as robust and exhibited increased cell-to-cell variability. Science , this issue p. [1433][1] [1]: /lookup/doi/10.1126/science.aah4115