Contribution of interferon-γ in protecting mice during pulmonary and disseminated infection withCryptococcus neoformans

Abstract

In the present study. the role of interferon-γ (IFN-γ) in the host resistance against Cryptococcus neoformans was examined using a murine model of pulmonary and disseminated infection. In this model, mice were infected intratracheally with live yeast cells, and the histological changes in the lungs and the number of microorganisms in the lung and brain were compared in mice treated and untreated with anti-IFN-γ monoclonal antibody (mAb) to define the contribution of endogenously synthesized IFN-γ in the natural course of infection. Administration of this mAb reduced the accumulation of inflammatory cells in the alveolar septa, peribronchial and perivascular areas, and promoted the expansive growth of microorganisms in the alveoli and destruction of alveolar structure. The neutralization of endogenous IFN-γ by mAb increased the number of microorganisms in the lung and brain, and significantly shortened the survival time of infected mice. On the other hand, administration of IFN-γ decreased the number of microorganisms in these organs, and significantly extended their survival time. Considered together, our results suggest that endogenous IFN-γ protects mice from infection with C. neoformans by inducing a cellular inflammatory response. potentiating the clearance of microorganism from the lungs and preventing its dissemination into the central nervous system.