Endogenous leukocyte rolling is significantly reduced in TNFα-treated CD44-deficient mice. CD44-deficient (CD44-KO) and their wild-type controls (wild-type) mice were treated with TNFα for 4 hours. (A) Endogenous leukocyte rolling flux, (B) rolling velocity, (C) the number of cells rolling per 100 μm, and (D) leukocyte adhesion in postcapillary venules of the small intestine were determined using intravital microscopy. Data are expressed as the arithmetic means ± SEM of at least 5 animals per group. *P < .05 relative to TNFα-treated wild-type animals.