Two subsets of CD8⁺ T cells are retained within human lymphoid tissues.

<p>The co-expression of CD69 and CD103 by CD8⁺ T cells isolated from spleen and tonsils were determined by flow cytometry. (A and B) Representative flow cytometry plots (left) and graphs (right; mean ± SEM; n = 10) show the proportion of CD69⁺CD8⁺ T cells expressing CD103 in human spleen (A) and tonsils (B). (C—E) Representative flow cytometry plots showing the expression levels of CCR7, CD45RA and CD11a between CD69^—CD103^—(blue), CD69⁺CD103^—(red) and CD69⁺CD103⁺ (green) CD8⁺ T cell subsets from the spleen (C) and tonsils (D) and the expression of PD-1, TIM3 and BTLA in tonsils (E). Data is representative of 3–5 independent experiments. (F) Relative expression of <i>KLF2</i> and <i>S1PR1</i> in purified CD8⁺ T subsets from the spleen (left panels) and tonsils (right panels). Individual dots represent different donor samples (n = 8 for spleen and n = 3 for tonsils). Statistical analysis was performed using one-way ANOVA and Tukey test. P<0.05 is noted with * and P<0.0005 is noted with ***.