Fig 6. Immunogenicity of proteins is enhanced as the result of oxidation by endogenous, neutrophils-derived HOCl.

(A) Luminol- or lucigenin-enhanced chemiluminescence stimulated by zymosan (Zym) or heat-killed S. aureus (Sa) in WT and MPO-/- neutrophils. (B) Presentation of OVA, as assessed by IL-2 production, by PEM pre-incubated with OVA, S. aureus and WT or MPO-/- neutrophils (PMN) to subsequently added CD4⁺ OT-II lymphocytes. (C) Uptake of pHrodo-labelled native or HOCl-oxidised YAD or HSA by BM-DC, assessed by flow cytometry. Results of single experiments shown were repeated 2 more times with similar results. (D) Titers of YAD-specific IgG in sera of mice primed with 20 μg YAD and hot alkali-treated zymosan or TNF-α plus WKYMVm peptide and boosted 2 weeks later with 20 μg of YAD alone. Sera were collected 8 days after the boost immunization and titers of YAD-specific IgG were determined by ELISA. Points represent titer values in individual mice and horizontal lines geometric means. Statistical analysis was performed with ANOVA, followed by the Tukey-Kramer post-test, to compare all pairs of groups (B, D) or by the Dunnett’s test, to make comparisons with the control group (“Autofluor.”) (C). *, p < 0.05; NS, non-significant.