Single-cell expression profiles of the most differentiated CD8⁺ T-cell subpopulations. αβ-TCR⁺ CD8⁺ PBLs were subdivided by their expression of CCR7, CD45RA, CD27, and CD28, and individual cells from each subset were sorted and studied as described in Figure 2. Each single cell corresponds to 1 horizontal row, whereas the expression of the several genes studied is depicted vertically. The representative gene expression patterns presented correspond to (A) DP, (B) CD28-SP, (C) CD27-SP, and (D) DN CCR7⁻CD8⁺ T subsets. Each profile is from 1 representative donor of 3, with the exception of the minority CD28-SP set, which we could isolate only from this donor. The genes, ccl5, ccl4, tgfb1, tnf, lta, ifng, prf1, gzma, gzmb, faslg, tgfbr1, tgfbr2, ifngr2, and il10ra, code, respectively, for RANTES, MIP-1β, TGF-β1, TNF-α, TNF-β, IFN-γ, perforin, GZMA, GZMB, Fas-L, TGF-βR1, TGF-βR2, IFN-γR2, and IL-10Rα.