Contribution of the CXCL1-CXCR2 axis to leukocyte adhesion within the cerebral vasculature in response to bacterial toxins. a, Micrographs of intravascular leukocytes (arrows) with a rod-shaped or rounded morphology in mouse brain sections stained for CD45 by immunohistochemistry. Arrowheads = microglial processes. Scale bar = 5 μm. b, Counts of CD45+ intravascular leukocytes (rod-shaped and round) in the cerebral cortex of mice treated with anti-CXCL1, anti-CXCR2, or isotype antibody (4 mg/kg), and killed 6 h after intraperitoneal injection of PBS, PTX (20 μg/kg), or LPS (1 mg/kg). The means were compared using ANOVA (P-values as indicated) followed by post hoc Student's t tests. *Significantly different from the corresponding isotype group. n = 6-10 per group. c, Data from an experiment similar to the one shown in b, except that LPS-challenged mice received a higher dose of anti-CXCL1 antibody (20 mg/kg instead of 4 mg/kg) or a combination of anti-CXCL1 and anti-CXCL2 antibodies (4 mg/kg each). n = 7 per group.