Neutrophil-DC hybrids function as professional phagocytes in bacterial peritonitis lesions. (A-B) At 48 hours after thioglycollate treatment, C57BL/6 mice received intraperitoneal inoculation of E. coli expressing GFP. (A) One hour later, PECs were examined for GFP fluorescence signals (means ± SD, n = 3) for Ly6G⁺/CD11c⁻ neutrophils, Ly6G⁺/CD11c^high neutrophil-DC hybrids, and Ly6G⁻/CD11c^high traditional DCs. (B) Fluorescence (left), phase contract (middle), and merged images (right) are shown for the FACS-purified Ly6G⁺/CD11c^high hybrid population (bar indicates 20 μm). (C-D) C57BL/6 mice (C) or CD11c promoter-driven DTR-EGFP TG mice (D) received systemic injections of DT or PBS alone on days 0 and 2 and thioglycollate treatment on day 1. The mice were challenged with intraperitoneal inoculation of E. coli on day 3 and then examined for the numbers (means ± SD from 3 mice per panel) of live bacteria recovered from the peritoneal cavities at the indicated time points (C) or after 30 minutes (D). (D) Ly6G⁺/CD11c^high/MHC II⁺ neutrophil-DC hybrids or Ly6G⁻/CD11c^high/MHC II⁺ DCs purified from the PECs from the second panel of thioglycollate-treated C57BL/6 mice were intraperitoneally injected together with E. coli to test their ability to restore bacterial clearance in the DC-depleted mice. *P < .05; **P < .01 between the indicated samples. Data are representative of at least 2 independent experiments.