Figure 2. Expression of Ly108 and CX₃CR1 define three subsets of CD8⁺ T cells during chronic viral infection.

(A) tSNE plot highlighting the three main subsets of CD8⁺ T cells present after establishment of chronic viral infection. (B) Representative flow plots depicting Ly108⁺, CX₃CR1⁻Ly108⁻ and CX₃CR1⁺ GP₃₃⁺ splenic CD8 subsets on day 14 p.i. (C) Kinetics (mean +/− SEM) of subsets in the spleen. Viremia (mean +/− SEM) kinetics overlayed in shaded yellow. (D) Representative flow plots depicting GP₃₃⁺ CD8⁺ T cell subsets in indicated tissues on day 14 p.i. (E) Frequency of CD8⁺T cell subsets in different anatomical locations. (F-G) Representative flow plots (F) and summary data (G) showing relative expression of surface molecules in GP₃₃⁺ subsets on days 21-30 p.i. (H-I) Representative flow plots (H) and summary data (I) showing relative expression of TFs in GP₃₃⁺ subsets (J) Representative flow plots and summary data showing proportion of Ly108⁺, CX₃CR1⁻Ly108⁻ and CX₃CR1⁺ subsets degranulating (CD107a⁺) and producing IFN-γ or co-producing TNF-α and IFN-γ⁺ upon ex vivo GP_33-41 stimulation. (K) Flow plot and summary data showing granzyme B expression in GP₃₃⁺ subsets. (L) Summary data depicting relative cytotoxicity of Ly108⁺, CX₃CR1⁻ Ly108⁻ and CX₃CR1⁺ subsets against peptide-pulsed target EL4 cells. GP₃₃-specific subsets were sort-purified on day 21 p.i. and cultured with target cells at a 5:1 ratio. Data (Mean+/− S.D. in E,G, I-K or Mean+/− S.E.M. in (L)) are from 3-8 mice and are representative of at least 3 independent experiments.*p<0.05 **p<0.01, ***p<0.0001. See also Figure S4.