Departamento de Microbiologia, Laboratório de Micologia Médica - LIM53 - Hospital de Clínicas, Faculdade de Medicina, Instituto de Ciências Biomédicas, Universidade de São Paulo, São Paulo, Brasil .
Mem Inst Oswaldo Cruz. 2009 Jul;104(4):644-8. doi: 10.1590/s0074-02762009000400019.
Paracoccidioides brasiliensis, a thermal dimorphic fungal pathogen, produces a melanin-like pigment in vitro and in vivo. We investigated the involvement of carbohydrates and monoclonal antibody to CD18, on phagocytosis inhibition, involving macrophage receptors and the resistance of melanized fungal cells to chemically generated nitric oxide (NO), reactive oxygen species (ROS), hypochlorite and H2O2. Our results demonstrate that melanized yeast cells were more resistant than nonmelanized yeast cells to chemically generated NO, ROS, hypochlorite and H2O2, in vitro. Phagocytosis of melanized yeast cells was virtually abolished when mannan, N-acetyl glucosamine and anti-CD18 antibody were added together in this system. Intratracheal infection of BALB/c mice, with melanized yeast cells, resulted in higher lung colony forming units, when compared to nonmelanized yeast cells. Therefore, melanin is a virulence factor of P. brasiliensis.
巴西副球孢子菌是一种温度双相真菌病原体，在体外和体内都会产生一种类似于黑色素的色素。我们研究了碳水化合物和抗 CD18 单克隆抗体在吞噬作用抑制中的作用，涉及巨噬细胞受体和黑色素化真菌细胞对化学产生的一氧化氮 (NO)、活性氧 (ROS)、次氯酸盐和 H2O2 的抗性。我们的结果表明，与非黑色素化酵母细胞相比，黑色素化酵母细胞在体外对化学产生的 NO、ROS、次氯酸盐和 H2O2 具有更强的抗性。在这个系统中，当甘露聚糖、N-乙酰葡萄糖胺和抗 CD18 抗体一起添加时，黑色素化酵母细胞的吞噬作用几乎被完全抑制。与非黑色素化酵母细胞相比，用黑色素化酵母细胞经气管内感染 BALB/c 小鼠后，肺部集落形成单位数更高。因此，黑色素是巴西副球孢子菌的毒力因子。
