HA mediates neutrophil adhesion in hepatic sinusoids in response to systemic endotoxemia. Untreated WT mice (white bar) and mice treated with LPS i.v. for 4 h (black bar) were compared with WT mice treated i.v. with HNase 2 h before i.v. LPS. One group of WT mice received a neutrophil-depleting concentration of anti–Gr-1 antibody 24 h before LPS treatment. Intravital microscopy was used to measure the (A) number of rolling leukocytes and (B) the number of adherent leukocytes per 100 μm in postsinusoidal venules, and (C) the number of adherent leukocytes per field of view in sinusoidal capillaries. (D) Leder-stained histological sections of livers from untreated and LPS-treated mice were examined by light microscopy, and positively stained neutrophils were counted per hpf (×400) of view. Data are presented as the arithmetic mean ± SEM of at least five animals per group. *, P < 0.05 relative to untreated controls; #, P < 0.05 relative to LPS-treated WT animals.