Temporal changes in systemic chemokine levels during SEB-induced TSS. Twelve- to 14-week-old HLA-DR3 transgenic mice were challenged as indicated. Groups of mice (four to six mice per group) were sacrificed at indicated times, and serum cytokine levels were determined using a multiplex suspension array system (Bio-Plex; Bio-Rad Laboratories, Inc., Hercules, CA). Bars represent mean ± SE values for four to six mice. Unpaired Student's t-test was used to determine statistical significance using PRISM software (version 3.0a; GraphPad Software Inc., San Diego, CA). *P < 0.05 with SEC 50 µg.