Figure 5. Key role of hypochlorite (HOCl) in triggering NETs.

(A,B) Human neutrophils (2×10⁶ cells/well) were pre-treated with ABAH, and then stimulated with either H₂O₂ or NaOCl. MPO inhibition blocked H₂O₂-stimulated but not NaOCl-stimulated NETosis, as seen with (A) microscopy and (B) quantification of extracellular DNA release, indicating that HOCl is the central oxidant species that triggers NET formation in human neutrophils. All conditions were done in triplicate. (C) Stimulated human neutrophils incubated in minimal media with or without Cl⁻ were treated with exogenous H₂O₂ or NaOCl at indicated concentrations. In the absence of Cl⁻, human NETosis was rescued by addition of exogenous NaOCl, but not by H₂O₂, again illustrating that HOCl represents the central oxidant species for NET formation. All conditions were done in triplicate.