FLORES-GARCIA, Aurelio et al. Exogenous interleukin-12 prevents the decrease in myeloperoxidase activity of macrophages in gerbils with sporotrichosis. []. , 33, 1, pp. 52-60. ISSN 0864-0300.

Introduction: interleukin-12 is an immunoregulatory cytokine with multiple biologic functions, including macrophage activation. Myeloperoxidase is an enzyme that plays an important role in the antimicrobial function of activated phagocytes. In the presence of hydrogen peroxide, myeloperoxidase catalyzes chloride oxidation to produce hypochlorous acid, a powerful microbicidal agent. Objective: determine the stimulating effect of murine recombinant interleukin-12 on myeloperoxidase activity in peritoneal macrophages of gerbils experimentally infected with Sporothrix schenckii yeasts. Methods: 500 ng murine recombinant interleukin-12 were administered intraperitoneally on a daily basis on 5 consecutive days to male gerbils. On the sixth day the gerbils were inoculated subcutaneously on the left posterior plantar pad with 6x10⁶ S. schenckii yeasts. Seven days after infection, macrophages were obtained from the peritoneal cavity. Myeloperoxidase activity was determined by Kaplow's method and expressed as percentage of peritoneal macrophage activity. Results are expressed as the average percentage of myeloperoxidase activity ± standard deviation from 3 independent experiments. Statistical differences between groups were evaluated by Student's t test. A value of p < 0.05 was considered significant. Results: administration of murine recombinant interleukin-12 to gerbils following infection with S. schenckii significantly increased the myeloperoxidase activity of peritoneal macrophages (p = 0.0001) in comparison with healthy controls. Macrophages of untreated infected gerbils, however, showed significantly reduced myeloperoxidase activity in comparison with healthy controls (p= 0.001), suggesting poor macrophage activation. Conclusions: in vivo administration of murine recombinant interleukin-12 before infection with S. schenckii induces macrophage activation evidenced by an increase in myeloperoxidase activity, enhancing the organism's defense against that infectious agent via the myeloperoxidase-dependent oxidative system.

: interleukin-12; macrophages; Sporothrix schenckii; myeloperoxidase.

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