Fig. 1. L-selectin (CD62L) density (number of PE molecules bound per cell) in response to a speaking and an exercise task. In response to public speaking (top), the surface density of CD62L was decreased, but not significantly, on mixed lymphocytes, CD8⁺ cytotoxic cells, and CD4⁺ helper T cells. In response to exercise (bottom), the surface density of CD62L was significantly decreased on mixed lymphocytes, CD8⁺ cytotoxic cells, and CD4⁺ helper T cells (p values < .001).