Gilmore B J, Retsinas E M, Lorenz J S, Hostetter M K
Department of Pediatrics, University of Minnesota, Minneapolis.
J Infect Dis. 1988 Jan;157(1):38-46. doi: 10.1093/infdis/157.1.38.
Heretofore, the existence of membrane receptors for biologically active fragments of mammalian complement proteins has been confined to mammalian cells, where these receptors serve to protect the host by triggering multiple aspects of the phagocytic response to microbial invasion. In this study, we show that surface receptors for the C3 fragment iC3b are present on the yeast Candida albicans, where they promote the pathogenicity of this organism by inhibiting phagocytosis. These receptors share homology with the alpha-chain, but not with the beta-chain, of neutrophil receptors for iC3b, as determined by the binding of monoclonal antibodies, and are induced by mycelial transformation of the yeast and by high concentrations of glucose. Blockade of these receptors by monoclonal antibodies significantly augments phagocytosis for those strains studied. By binding iC3b noncovalently, these receptors impair phagocytic uptake of C. albicans by human polymorphonuclear leukocytes.
迄今为止，哺乳动物补体蛋白生物活性片段的膜受体仅存在于哺乳动物细胞中，这些受体通过触发对微生物入侵的吞噬反应的多个方面来保护宿主。在本研究中，我们发现酵母白色念珠菌表面存在C3片段iC3b的受体，这些受体通过抑制吞噬作用促进该生物体的致病性。通过单克隆抗体的结合确定，这些受体与中性粒细胞iC3b受体的α链具有同源性，但与β链没有同源性，并且由酵母的菌丝体转化和高浓度葡萄糖诱导产生。单克隆抗体对这些受体的阻断显著增强了所研究菌株的吞噬作用。通过非共价结合iC3b，这些受体损害了人类多形核白细胞对白色念珠菌的吞噬摄取。
