Kinetics of CXC chemokine appearance after endotoxin injection. Kinetics of CXC chemokine appearance after endotoxin injection. Each of the measured CXC chemokines peaked within 2 h of endotoxin injection. Note that the values of KC and macrophage inflammatory protein 2 in the mouse were significantly higher than IL-8 or growth-related oncogene-α in humans. Each value is the mean ± SEM (error bar) for 13 humans or 11 mice. Conc., concentration. Shannon Copeland et al. Clin. Diagn. Lab. Immunol. 2005; doi:10.1128/CDLI.12.1.60-67.2005