Rac1 and Rac2 are required for chemokine-induced chemotaxis and adhesion of T cells. (A) Graph shows mean ± SEM percentage migration of T cells in a Transwell assay in response to CCL21, CCL19, CXCL12, or in the absence of chemokine. (B) Graph shows mean ± SEM percentage adhesion of T cells of the indicated genotypes to immobilized ICAM-1 in response to CCL21, Mn2+, or no stimulus. Data are from 4 independent experiments. *P < .05; **P < .01; ***P < .001.