Metabolic activity of phagocytes in experimental sporotrichosis.

Phagocytosis plays an important role as a protective mechanism against infections, since polymorphonuclear leukocytes (PMN) and macrophages are the first cellular lines opposed to aggressive microorganisms. In patients with sporotrichosis a diminished capability of killing engulfed yeast by their PMN has been described, but the origin of this deficiency remains unknown. In this work, partial aspects of the oxidative metabolism of PMN leukocytes and peritoneal macrophages of mongolian gerbils experimentally infected with sporotrichosis were studied. For this purpose the nitroblue tetrazolium (NBT) test as described by Baehner and Nathan (1) and myeloperoxidase activity measured according to Kaplow's method were utilized. The PMN and macrophages of mongolian gerbils infected with sporotrichosis showed increased reduction of NBT when compared with the phagocytic cells of normal ones, as is usually observed in most infections. Myeloperoxidase activity was diminished in both PMN and macrophages, but this diminution was statistically significant only in PMN leukocytes. These results show that part of the oxidative mechanisms of phagocytic cells can be impaired in experimental sporotrichosis, and could be correlated with the diminished fungicidal activity of PMN leukocytes obtained from patients infected with sporotrichosis.