Abstract HSF1 alleviated multiple organ damage and PMN infiltration in mice by suppressing the surface expression of PSGL-1 and CD11b on PMNs during endotoxemia. We have reported previously that HSF1 is essential in protection against the lethal systemic inflammation induced by LPS. However, the mechanism by which HSF1 protects against LPS-induced systemic inflammation remains unknown. In this study, HSF1−/− mice were subjected to endotoxemia by a bolus injection of LPS (10 mg/kg, i.p.). The serum levels of LDH, BUN, and transaminase (ALT and AST) were measured. PMN infiltration in lung, liver, and kidney tissues after endotoxemia was observed with immunohistochemistry. Comparing with the WT control, LPS administration induced more severe multiple organ dysfunction and lower survival rates in the HSF1−/− mice. Moreover, PMN infiltration into lungs, liver, and kidneys in HSF1−/− mice was more than that in the WT mice. The augmented tissue PMN infiltration in HSF1−/− mice was associated with their enhanced adhesive properties to endothelium in vivo. In addition, HSF1−/− caused greater surface expression of PSGL-1 and CD11b on the PMN surface after LPS treatment. These findings suggested that HSF1 alleviated LPS-induced multiple organ injury in mice by suppressing the surface expression of adhesion molecules on PMNs and subsequent infiltration of PMNs in tissues.