Muscle-infiltrating T cells are CD4⁺ and express CD25 and CD69.

(A–B) Flow cytometric analysis of CD4 and CD8 expression on CD3+ T cells harvested from injured skeletal muscle. A representative plot from day 3 is shown at left and data are summarized at right as % CD4+ or % CD8+ at each time point analyzed (n ≥ 4 mice per time point, mean ± SEM). (C–D) The majority of CD3+CD4+ cells express CD25 (range: 86–97%), CD69 (34–66%), but not CD44 (0.1–4%) (n ≥ 4 mice per time point, mean ± SEM).