García-Rodas Rocío, Zaragoza Oscar
Mycology Reference Laboratory, National Centre for Microbiology, Instituto de Salud Carlos III, Madrid, Spain.
FEMS Immunol Med Microbiol. 2012 Mar;64(2):147-61. doi: 10.1111/j.1574-695X.2011.00871.x.
After inhalation of infectious particles, Cryptococcus neoformans resides in the alveolar spaces, where it can survive and replicate in the extracellular environment. This yeast has developed different mechanisms to avoid internalization by phagocytic cells, the main one being a polysaccharide capsule around the cell body, which inhibits the uptake of the yeast by macrophages. In addition, capsule-independent mechanisms have also been described, such as the production of antiphagocytic proteins. Despite these mechanisms, phagocytosis can occur in the presence of opsonins, and once C. neoformans is internalized, multiple outcomes are possible, including pathogen killing or intracellular replication and escape from macrophages. For this reason, C. neoformans is considered a facultative intracellular pathogen. As alveolar macrophages are the first component of the host immune system to confront C. neoformans, the outcome of this interaction could determine the degree of infection, producing either a severe disseminated disease or a latency state. In this review, we will tackle the complexity of the interaction between C. neoformans and macrophages, including the phagocytic avoidance mechanisms and all the possible outcomes that have been described for this interaction. Finally, we will discuss the consequences of the different outcomes for the type of infection produced in the host.
吸入感染性颗粒后，新型隐球菌驻留在肺泡腔中，它可以在细胞外环境中存活和复制。这种酵母已发展出不同机制以避免被吞噬细胞内化，其中主要机制是在细胞体周围形成多糖荚膜，这会抑制巨噬细胞对酵母的摄取。此外，还描述了不依赖荚膜的机制，例如产生抗吞噬蛋白。尽管有这些机制，但在存在调理素的情况下仍可发生吞噬作用，一旦新型隐球菌被内化，可能会出现多种结果，包括病原体被杀死、在细胞内复制以及从巨噬细胞中逃脱。因此，新型隐球菌被认为是兼性细胞内病原体。由于肺泡巨噬细胞是宿主免疫系统中最先接触新型隐球菌的成分，这种相互作用的结果可能决定感染程度，引发严重的播散性疾病或潜伏状态。在这篇综述中，我们将探讨新型隐球菌与巨噬细胞相互作用的复杂性，包括吞噬逃避机制以及针对这种相互作用所描述的所有可能结果。最后，我们将讨论不同结果对宿主体内产生的感染类型的影响。
