%0 Journal Article %A Brummer, E. %A Kurita, N. %A Yoshida, S. %A Nishimura, Kazuko %A Miyaji, M. %T Killing of Histoplasma capsulatum by γ-interferon-activated human monocyte-derived macrophages: evidence for a superoxide anion-dependent mechanism %D 1991 %J Journal of Medical Microbiology, %V 35 %N 1 %P 29-34 %@ 1473-5644 %R https://doi.org/10.1099/00222615-35-1-29 %I Microbiology Society, %X Summary The interaction of human macrophages with the yeast form of the thermally dimorphic fungal pathogen, Histoplasma capsulatum, was studied. Macrophages derived from monocytes by culture in vitro for 3 days ingested H. capsulatum, but were neither fungicidal or fungistatic. In contrast, when monocytes were exposed to human recombinant gamma-interferon (γ-IFN) during their differentiation into macrophages, those macrophages were able to reduce the number of ingested or adherent cfu of H. capsulatum by 44-75% in 2 h. Activation of macrophages for fungicidal activity by γ-IFN was dose dependent and 500-1000 units ml were optimal. Antibody to γ-IFN abrogated the γ-IFN activation process. Killing of H. capsulatum by activated macrophages in 2-h assays could be inhibited by superoxide dismutase but not by sodium azide. %U https://www.microbiologyresearch.org/content/journal/jmm/10.1099/00222615-35-1-29