Polymorphonuclear neutrophil participation in immune response to Paraccocidioides brasiliensis

Abstract

Paracoccidioidomycosis, a systemic mycosis of great importance in Latin America, is histologically characterized by an acute inflammatoty response in the lung target organ. During the early stages of infection, tissue response is mainly characterized by the presence of polymorphonuclear neutrophils (PMN) which represent over 85% of all cells (demonstrated by histopathology and bronchoalveolar lavage). Evidence is presented herein that PMNs actively participate during the acute inflammatory response induced by Paracoccidioides brasiliensis. This is shown by growth inhibition following the interaction of the fungus with these phagocytic cells. Certain of the killing mechanisms exhibited by this phagocytic cell are mediated by the reactive oxygen intermediates, as well as by the activating mechanisms exerted by certain cytokines (IFN-y, GM-CSF and IL-1B). Furthermore, fungal fractions or components are capable of inducing both activation of PMN and migration to the inflammatory site as revealed by the increase of the products resulting from the respiratoty burst.