Cryptococcus.
Cryptococcus.
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隐球菌。
DOI：
10.1016/j.cub.2012.05.040
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发表时间：
2012
期刊：
影响因子：
--
通讯作者：
Nielsen,Kirsten
中科院分区：
文献类型：
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作者：
McDonald,Tami;Wiesner,DarinL;Nielsen,Kirsten
杂志 R555 被吞噬细胞降解（图 1）。从细胞中解离出来的多糖也会抑制 T 细胞和细胞因子反应，这种奇怪的特性促使人们研究使用纯化的隐球菌胶囊作为某些形式的自身免疫的潜在疗法。嵌入糖衣正下方的细胞壁中含有一种色素黑色素，它能够清除宿主细胞释放的氧自由基，从而防止氧化损伤并促进吞噬细胞内的存活。该色素还会与常规杀菌剂结合并降低药效。当酵母在环境中生长时，黑色素通过允许真菌在较宽的温度范围内生长、在高浓度的有毒金属中生存并抵抗电离辐射而赋予其健康优势。隐球菌还形成被称为“泰坦细胞”的巨大细胞，这些细胞太大而吞噬细胞无法吞噬（图 1），能够保护正常隐球菌细胞免受宿主免疫反应的影响，并在疾病的形成中发挥关键作用。最后，其中一种性别（α交配型）在环境和临床中更为普遍。 α细胞是双性的——它们与相反的交配类型进行异性交配，但也是同性恋，能够通过同性交配繁殖。这些特征共同将隐球菌与许多其他人类病原体区分开来。
Magazine R555 degradation by phagocytes (Figure 1). Polysaccharide that has dissociated from the cell also inhibits T-cell and cytokine responses, and this curious property has prompted investigation into using purified Cryptococcus capsule as a potential therapy for some forms of autoimmunity. Embedded in the cell wall, directly below the sugar coat, resides a pigment, melanin, that is capable of scavenging oxygen radicals deployed by host cells, thereby preventing oxidative damage and promoting survival inside phagocytes. The pigment can also bind to conventional fungicides and reduce drug efficacy. When the yeast is growing in the environment, melanin confers a fitness advantage by permitting the fungus to grow at wide temperature ranges, survive in high concentrations of toxic metals, and resist ionizing radiation. Cryptococcus also forms gigantic cells dubbed ‘titan cells’, which are too large for phagocytes to engulf (Figure 1), are able to protect normal cryptococcal cells from the host immune response, and play a key role in establishment of disease. Finally, one of the sexes (the α mating type) is more prevalent in both the environment and the clinic. The α cells are bisexual—they undergo heterosexual mating with the opposite mating type, but are also homosexual, able to propagate by same-sex mating. These traits collectively distinguish Cryptococcus from many other human pathogens.