Short report: Inhibition by tumor necrosis factor-�-activated macrophages of the transition of Paracoccidioides brasiliensis conidia to yeast cells through a mechanism independent of nitric oxide

Abstract. It is known that peritoneal murine macrophages activated with interferon- exert a fungicidal effect against Paracoccidioides brasiliensis conidia by a nitric oxide (NO)−mediated mechanism. This NO-mediated effect can also be induced by other cytokines such as tumor necrosis factor- (TNF-). The aim of this study was to determine if TNF-−activated peritoneal murine macrophages infected with P. brasiliensis were able to show fungistatic/fungicidal effects mediated by NO. The results indicated that although macrophage activation with TNF- did not result in NO production, these cells played an important role in inhibiting the conidia from becoming yeast cells. In vivo, the NO-independent inhibitory effect would prove of importance for the establishment of P. brasiliensis in host tissues. Paracoccidioidomycosis (PCM) is one of the most impor-tant endemic mycoses in Latin America, and Colombia is one of the countries where the disease is frequently diagnosed.1 This disease is a progressive, chronic disorder caused by the inhalation of the infective particles (conidia) produced by the mycelial form of the fungus Paracoccidioides brasiliensis. The mycosis affects primarily the lungs, but it can disseminate into other organs and systems.