Figure 5.

Heme and Fe⁺² induce neutrophil activation and antioxidant mechanisms in infected neutrophils. Human neutrophils were infected with L. infantum in the presence of heme (30 µM) or Fe⁺² (100 µM). The culture supernatants were used to assess production of myeloperoxidase (MPO) (A) and neutrophil elastase (NE) (B) using an enzymatic activity assay. Superoxide dismutase (SOD) activity was measured in the culture supernatants as described in Section “Materials and Methods” (C). Heme oxygenase-1 (HO-1) mRNA expression was analyzed by real time-PCR (D). Each point on the graph represents a donor, and the bars represent the median vales. Data were compared using the Kruskal–Wallis test with Dunn’s post-test. *p < 0.1, **p < 0.01, ***p < 0.001.