Delayed GM6001 infusion inhibits syndecan-1 shedding, removal of CXC chemokines in tissues, and resolution of neutrophilic inflammation. WT mice were injected intraperitoneally with or without 150 mg GM6001/kg at 24 hours after LPS, and tissue samples were analyzed at 40 hours after LPS. Syndecan-1 shedding was assessed by (A) immunostaining lung and liver sections (original magnification, ×200) and (B) measuring serum levels of syndecan-1 ectodomains (n = 4). (C) Tissue levels of KC and MIP-2 were determined by ELISA (n = 4). (D) Neutrophil accumulation was assessed by immunostaining with anti-GR1 and Alexa 594 anti–rat antibodies (original magnification, ×200). Error bars indicate SE.