NATURAL CELL-MEDIATED RESISTANCE IN CRYPTOCOCCOSIS

隐球菌病在危及患者生命的感染中排名第四 患有获得性免疫缺陷综合征(艾滋病)，这种疾病是一种 细胞受损的个体经常出现严重的问题- 介导的免疫反应。尽管已经很好地确定了CD4 淋巴细胞依赖的免疫反应对于保护是必不可少的 对于新生隐球菌，自然效应细胞具有显著的作用 为有效的一线宿主防御做出贡献，并通过激活 通过免疫T细胞产生的细胞因子，也可能发挥效应器的作用 获得性豁免权。我们之前已经证明了小鼠NK细胞 细胞在体外直接与新生芽孢杆菌相互作用并损伤 有机体。此外，我们和其他人已经表明，NK细胞 参与清除感染组织中的隐球菌。我们现在 建议扩大我们对小鼠NK细胞的研究，以确定 这些细胞还通过分泌细胞因子间接抑制新生葡萄球菌。 它们增强了天然吞噬细胞的抗隐球菌活性 效应细胞。NK细胞培养上清与C. 将对新生杆菌进行肿瘤坏死因子、γ干扰素检测 和集落刺激因子通过功能生物测定和酶联免疫吸附试验，以及 NK细胞中细胞因子的诱导将通过演示得到证实 应用原位杂交技术检测细胞因子特异性信使RNA。细胞因子 含有新生芽孢杆菌刺激的NK细胞的上清液， 相比之下，重组细胞因子将被评估其能力 激活多形核白细胞和巨噬细胞 有效地杀死了隐球菌。 虽然小鼠和人NK细胞的功能活性 相似的是，这两类细胞识别不同的肿瘤细胞 目标。因此，建议进行研究，以检查 健康献血者NK细胞的抗隐球菌活性。在我们的 初步研究，人外周血中NK细胞以及T细胞 细胞，附着在和损坏的隐球菌细胞。我们建议定义 人的超微结构和表型特征 外周血淋巴细胞与新生葡萄球菌和 比较和对比两种不同人群的人体效应器 关于隐球菌细胞的要求 互动。此外，我们将确定淋巴因子激活的NK细胞 细胞表现出比新鲜细胞更强的直接抗隐球菌活性 分离的NK细胞和人类NK细胞是否有能力 通过细胞因子的产生间接参与促进 其他天然效应细胞的抗隐球菌活性。考虑 NK细胞在隐球菌病宿主防御中的潜在作用 重要的是要剖析小鼠和人类NK细胞的机制 抑制新生葡萄球菌生长及其免疫调节作用的研究 NK细胞介导的抗隐球菌病可能涉及的细胞因子 抵抗。

Cryptococcosis ranks fourth in life-threatening infections in patients with acquired immune deficiency syndrome (AIDS, and the disease is a frequent and serious problem in individuals with compromised cell- mediated immune responses. Although it is well established that CD4 lymphocyte-dependent immune responses are essential for protection against Cryptococcus neoformans, natural effecotr cells make significant contributions to effective first-line host defense and, via activation by cytokines produced by immune T cells, may also function as effectors of acquired immunity. We have previously demonstrated that murine NK cells directly interact in vitro with C. neoformans and damage the organism. In addition, we and others have shown that NK cells participate in clearance of ryptococci from infected tissues. We now propose to extend our investigations of murine NK cells to determine if these cells also inhibit C. neoformans indirectly by secreting cytokines which potentiate the anti-cryptococcal activity of phagocytic natural effector cells. Culture supernatants from NK cells incubated with C. neoformans will be assayed for tumor necrosis factor, gamma interferon and colony stimulating factors by functional bioassays and ELISA, and induction of cytokines in NK cells will be confirmed by demonstrating cytokine specific messenger RNA using in situ hybridization. Cytokine containing supernatants from C. neoformans-stimulated NK cells and, for comparison, recombinant cytokines will be assessed for their abilities to activate polymorphonuclear leukocytes and macrophages to more effectively kill cryptoccocci. Although the functional activity of murine and human NK cells are similar, these two populations of cells recognize different tumor cell targets. Studies are proposed, therefore, to examine the anticryptococcal activity of NK cells from healthy human donors. In our preliminary studies, human peripheral blood NK cells, as well as T cells, attached to and damaged cryptococcal cells. We propose to define the ultrastructural and phenotypic characteristics of the human peripheral blood lymphocytes which interact with C. neoformans and compare and contrast the two different populations of human effector cells with regard to the requirements for cryptococcal cell interactions. In addition, we will determine if lymphokine-activated NK cells display greater direct anticryptococcal activity than do freshly isolated NK cells and if human NK cells have the capability to participate indirectly via cytokine production to enhance the anticryptococcal activity of other natural effector cells. Considering the potential role of NK cells in host defense in cryptococcosis, it is important to dissect the mechanisms by which mouse and human NK cells restrict C. neoformans growth and to delineate the immunomodulatory cytokines which may be involved in NK cell-mediated anticryptococcal resistance.