LFA-1 expression on CD8⁺ T cells during acute LCMV infection. Expression of the activation/memory marker, LFA-1 (CD18), on CD8⁺ T cells in the spleen and femoral bone marrow of naive and LCMV-infected BALB/c mice was studied using FACS analysis. Splenic and bone marrow–localized CD8⁺ T cells exhibited similar patterns of LFA-1 surface expression that peaked at day 8 and then declined to homeostatic levels by 50 days postinfection. Data shown are representative of ≥3 independent experiments, each with similar results. CD8⁺ cells are shown on the vertical axis and LFA-1⁺ cells on the horizontal axis, with the ratio of LFA^lo:LFA^hi CD8⁺ T cells shown above each panel. Each dot plot represents 30,000 acquired events.