Cryptococcus neoformans Intracellular Proliferation and Capsule Size Determines Early Macrophage Control of Infection.
Cryptococcus neoformans Intracellular Proliferation and Capsule Size Determines Early Macrophage Control of Infection.
复制标题
DOI：
10.1038/srep21489
复制
发表时间：
2016-02-18
影响因子：
4.6
通讯作者：
Johnston SA
中科院分区：
文献类型：
--
作者：
Bojarczuk A;Miller KA;Hotham R;Lewis A;Ogryzko NV;Kamuyango AA;Frost H;Gibson RH;Stillman E;May RC;Renshaw SA;Johnston SA
新型隐球菌是免疫功能低下患者的重要真菌病原体。关于巨噬细胞在隐球菌感染的正常清除中的功能以及在不受控制的隐球菌病中存在的缺陷，仍然存在许多问题。目前的两个限制是：1）在感染进展的背景下解释使用分离的巨噬细胞的研究的困难，和2）在理解动物感染期间免疫细胞行为中使用高分辨率成像。在这里，我们描述了隐球菌病斑马鱼模型中的一种高内容成像方法，可以详细分析巨噬细胞与C的相互作用。感染期间的新生儿。使用这种方法，我们证明，虽然巨噬细胞是关键的控制C。对于新生儿，巨噬细胞反应的失败不是致命感染的限制性缺陷。我们发现吞噬作用在感染的早期就受到抑制，隐球菌数量的增加是由细胞内增殖驱动的。我们发现，巨噬细胞优先吞噬隐球菌与较小的多糖胶囊和胶囊的大小大大增加超过24小时的感染，这是足以严重限制进一步吞噬的变化。因此，隐球菌感染在体内的高内容成像显示了巨噬细胞和隐球菌之间的非常早期的相互作用是如何在隐球菌病的结果至关重要。
Cryptococcus neoformans is a significant fungal pathogen of immunocompromised patients. Many questions remain regarding the function of macrophages in normal clearance of cryptococcal infection and the defects present in uncontrolled cryptococcosis. Two current limitations are: 1) The difficulties in interpreting studies using isolated macrophages in the context of the progression of infection, and 2) The use of high resolution imaging in understanding immune cell behavior during animal infection. Here we describe a high-content imaging method in a zebrafish model of cryptococcosis that permits the detailed analysis of macrophage interactions with C. neoformans during infection. Using this approach we demonstrate that, while macrophages are critical for control of C. neoformans, a failure of macrophage response is not the limiting defect in fatal infections. We find phagocytosis is restrained very early in infection and that increases in cryptococcal number are driven by intracellular proliferation. We show that macrophages preferentially phagocytose cryptococci with smaller polysaccharide capsules and that capsule size is greatly increased over twenty-four hours of infection, a change that is sufficient to severely limit further phagocytosis. Thus, high-content imaging of cryptococcal infection in vivo demonstrates how very early interactions between macrophages and cryptococci are critical in the outcome of cryptococcosis.