Fig. 1: Engagement of FcγRs on mouse neutrophils generates nAPCs.

a, b Wild-type (WT) blood neutrophils treated with Ova, anti-Ova, or Ova-IC, cultured with GM-CSF and evaluated 3 days later by flow cytometry for survival and acquisition of CD11c and MHCII on Ly6G⁺ cells (left panel), and CD80, CD86, and CCR7 on Ly6G⁺CD11c⁺MHCII⁺ cells (right panel) (a). Representative gating strategy for Ova-IC generated nAPCs (b). c Neutrophils from CD45.1 (45.1) or CD45.2 (45.2) mice pre-treated with Ova or Ova-IC, or anti-Ova or Ova-IC, co-cultured with GM-CSF and analyzed for percent of Ly6G⁺ cells expressing CD11c and MHCII. d WT bone marrow neutrophils (BMN) pre-treated with SLE patient or normal human (NH) sera, or SLE-IgG+ RNP (SLE-ICs) or normal human sera-IgG+RNP, cultured without GM-CSF and analyzed as in (a). Representative FACS plots are shown. RNP alone resulted in 0.38 ± 0.11% conversion. e BMNs from WT, γ^−/−, FcγRIIIB(3B)/γ^−/− or FcγRIIA(2A)/γ^−/− mice treated with SLE or NH sera and analyzed as in (a). f Blood neutrophils from CD11c-YFP (yellow fluorescent protein) reporter mice treated with SLE-ICs, labeled with a nuclear stain and imaged at day 0 and 2 of culture for nuclear changes (i, iii) and CD11c induction (YFP positive) (ii, iv). Arrows: YFP⁺ cells with nuclear change. Arrowheads: Unconverted neutrophils. Scale bar = 5 μm; all images are at the same magnification. g Live cell imaging of cells treated as in (f). Representative images, taken at indicated hours, of nuclear changes and CD11c-YFP acquisition in tracked cells (left) and quantitation of the same (right). Scale bar = 5 μm; all images are at the same magnification. Data are mean ± s.e.m. a, d One-way analysis of variance and Dunnett’s multiple comparison test, c, e Student t-test for unpaired comparisons with Dunn-Bonferroni **p < 0.005, *p < 0.05.