TNFα-treated CD44-deficient mice exhibit reduced Th1 and Th2 rolling flux and adhesion compared with controls. Wild-type and CD44-deficient (CD44-KO) mice were treated with TNFα for 4 hours prior to intravenous injection of rhodamine 6G–labeled Th1 or Th2 lymphocytes. Intravital microscopy determined (A) Th1 rolling flux, (B) Th1 cell rolling velocity, and (C) Th1 cell adhesion. In similar experiments, Th2 rolling flux (D), Th2 rolling velocity (E), and Th2 adhesion (F) were also determined. Data are expressed as the arithmetic means ± SEM of at least 3 animals per group. *P < .05 relative to wild-type values.