Animal experiments were approved by the IACUC of BIDMC and done as per NIH guidelines. C57BL/6 wild-type (WT) mice were from Charles River Laboratories (Wilmington, MA). Panx1 knockout (panx1 KO) mice were from The Knockout Mouse Project Center for Comparative Medicine (University of California, Davis, CA) and backcrossed into a C57BL/6 background. Polymicrobial sepsis was induced by cecal ligation and puncture (CLP) as described (19 (link)). In some experiments, mice received i.p. injections of live E. coli (108) and remaining bacteria in the peritoneal cavity were determined after 2 h (19 (link)). Monocyte activation was assessed by flow cytometry using anti-CD11b and anti-Ly6C antibodies. Briefly, blood was collected by cardiac puncture, red blood cells lysed, leukocytes treated with Fc blocker (BD Biosciences), and labeled with PE-anti- Gr1 (clone: RB6–8C5), PerCP-anti-Ly6C (clone: HK1.4), and APC-anti-CD11b (clone: M1/70) antibodies (Thermo Fisher Scientific). Monocytes were identified by gating on Gr1-CD11b+Ly6C+ cells.