Visualizing NETs using chromatin antibodies or DNA-intercalating dyes. Human neutrophils were activated in vitro and then processed for immunofluorescence. An antibody directed against the subnucleosomal complex of H2A, H2B, and DNA stains intact, compact chromatin only weakly, but reacts strongly with relaxed chromatin in the NETs (A, red in D). In contrast, DNA-intercalating dyes provide the brightest staining at sites of high DNA concentrations, as is the case in compact nuclei, whereas NETs are stained rather weakly (A, Hoechst 33342; blue in D). (C, green in D) The granular marker NE, which can be observed in granules in cells that are not yet activated, as well as in NETs. A projection of confocal z-stack is shown. Bar, 10 µm.