Pathogenic differences between Cryptococcus neoformans and C. gattii

新型隐球菌和格特隐球菌的致病性差异

• 批准号: 10272062
• 负责人: Kyung Kwon-Chung
• 金额: $ 97.4万
• 依托单位: NATIONAL INSTITUTE OF ALLERGY AND INFECTIOUS DISEASES
• 依托单位国家: 美国
• 资助国家: 美国
• 起止时间: 至
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/10272062
• 关键词: Acquired Immunodeficiency Syndrome; Affect; Agrobacterium; Alanine; Amino Acids; Antibodies; Assimilations; Australia; Autoantibodies; Biological; Biology; Brain; CD4 Positive T Lymphocytes; CD8-Positive T-Lymphocytes; China; Classification; Clinical; Containment; Cryptococcosis; Cryptococcus; Cryptococcus gattii; Cryptococcus neoformans; Cryptococcus neoformans infection; Disease; Drug resistance; Ecology; Epidemiology; Etiology; Genes; Genomics; Granulocyte-Macrophage Colony-Stimulating Factor; Granuloma; Immune response; Immunocompetent; Immunocompromised Host; Immunoglobulin G; Immunologic Factors; Immunologics; Individual; Infection; Interferons; Iron; Libraries; Lung; Macroglobulins; Mediating; Molecular; Mus; Names; Natural Killer Cells; Neuraxis; Nitrogen; Organ; Pathogenicity; Patients; Pattern; Plasma; Poly I-C; Predisposing Factor; Proline; Risk; Risk Factors; Role; Sampling; Serum iron level result; Siblings; Source; Structure; base; cytokine; fungus; genetic makeup; macrophage; mutant; prevent; recruit; tool

In 2010, we initiated the construction of an insertional mutant library by the Agrobacterium mediated transformation of Cryptococcus gattii and isolated 30,000 mutant clones by the summer of 2011. This library will serve as a tool for identification of the genes that are involved in the manifestation of the pathobiological differences between the two species. During 2011-2012, we compared the pattern of nitrogen assimilation between C. gattii and C. neoformans and found striking differences in the utilization of D-amino acids such as D-proline and D-alanine. Furthermore, we discovered that the primary target organ for the two species in mice is different: the primary target organ for C. neoformans is the brain while for C. gattii, it is the lung. Since the host response toward the two species is clearly different, we initiated a study to compare the host-paracite relationship between the two species in 2013. Using the plasma samples from immunocompetent patients with cryptococcal menigitis in China and Australia, we found the presence of anti-GM-CSF autoantibodies in plasma to be a risk factor for C. gattii infection and not necessarily for C. neoformans infection. During 2015, we found an isolate of C. neoformans from an otherwise healthy GM-CSF autoantibody positive patient to be molecular type VNI which is the most common type of C. neoformans. This indicates that GM-CSF autoantibody is a more risk for C. gattii infection, it also can be a risk factor for C. neoformans. During 2015-2016, we compared the effect of exogenous Type 1 IFN in mice infected with the two species. For the exogenous type 1 IFN, we used Poly-IC which activates Type 1 IFN and found that poly-IC mediates protection of mice from both species. However, the immunological bases for poly-IC mediated protection was different between the two species. During C. neoformans infection, poly-IC treatment altered polarization of CD4 T helper cells from Th2 toward more protective Th1 and Th17 resulting in a corresponding change of polarization in recruited lung macrophages from M2 toward M1 polarization. Overall these immunological changes resulted in containment of the fungus within granuloma-like lung structures, thus preventing cryptococcal dissemination to central nervous system. However, these CD4 T helper cells were entirely dispensable for protection from C. gattii. During 2016-2017, we discovered that poly-IC mediated protection of mice from C. gattii required beta-2 macroglobulin (B2m)as B2m deficient mice displayed severly diminished protection. However, the immunological factors known to be affected by B2m (CD8 T-cells, NK cells and IgG antibody) were also shown to be dispensable for poly-IC protection. We found that B2m deficient mice had elevated levels of serum iron. We found that addition of exogenous unbound iron totally reversed poly-IC induced protection. During 2017-2018, our study confirmed the important role of iron levels in the lung for the protection of mice from C. gattii by exogenous activation of type I IFN. 2019, we have concluded that the reason for AIDS patients primarily suffer from cryptococcosis due to C. neoformans is the depletion of CD4+ T-cells while rarely getting infected by C. gattii which is unaffected by low CD4+ T-cells. During 2019-2020, we have identified a hither to unknown ecological source for C. gattii but not for C. neoformans.

在2010年，我们通过农杆菌介导的加蒂（Gattii）的加密环球球菌的转化启动了插入突变库文库，并在2011年夏季隔离了30,000个突变克隆。该文库将作为鉴定与两种病理生物学差异相关的基因的工具。在2011年至2012年期间，我们比较了C. gattii和Neoformans之间的氮同化模式，并发现在D-氨基酸（例如D-氨基酸和D-丙氨酸）的利用中存在明显的差异。此外，我们发现小鼠两种物种的主要靶孔是不同的：新近梭菌的主要靶器官是大脑，而对于gattii而言，是肺。由于宿主对这两种物种的反应显然是不同的，因此我们开始了一项研究，以比较2013年两种物种之间的宿主 - 半岩石关系。使用来自中国隐孢子虫薄膜炎的免疫能力患者的血浆样本在中国和澳大利亚中，我们发现在血浆中存在抗GM-CSF自动抗体的危险因素是C. gattiic。GattiiInctiftion C. and c. gatectional and C. Gattii and C. gatectional and and and and andiny andin and C. gattii and c. gatections and and and and and。在2015年期间，我们发现新的GM-CSF自身抗体阳性患者的Neoformans分离菌是分子型VNI，这是最常见的Neoformans类型。这表明GM-CSF自身抗体是C. gattii感染的风险更大，它也可能是新生梭菌的危险因素。在2015 - 2016年期间，我们比较了外源性1型IFN在感染这两种物种的小鼠中的作用。对于外源性1型IFN，我们使用了激活1型IFN的poly-IC，发现多-IC介导了对这两种物种的小鼠的保护。但是，两种物种之间用于聚-IC介导的保护的免疫碱不同。在NeoFormans感染期间，聚-IC处理改变了CD4 T辅助细胞从TH2到更保护性TH1和TH17的极化，从而导致募集的肺巨噬细胞从M2到M1极化发生了相应的极化变化。总体而言，这些免疫学变化导致颗粒状肺样结构内的真菌遏制，从而阻止了中枢神经系统的隐球菌传播。然而，这些CD4 T辅助细胞完全可以防止C. gattii保护。在2016-2017期间，我们发现对C. gattii对小鼠的介导的保护需要β-2大球蛋白（B2M），因为B2M缺陷小鼠的保护表现出严重减少的保护。然而，已知已知受B2M（CD8 T细胞，NK细胞和IgG抗体）影响的免疫因子也被证明可用于多IC保护。我们发现B2M缺乏小鼠的血清铁水平升高。我们发现，添加了外源未结合的铁完全逆转的多IC诱导的保护。在2017-2018期间，我们的研究证实了铁水平在肺中通过外源性IFN的外源激活来保护小鼠免受C. gattii的保护的重要作用。 2019年，我们得出的结论是，艾滋病患者的原因主要是由于新梭菌而引起的隐孢子球病是CD4+ T细胞的耗竭，而很少被C. gattii感染，而C. gattii不受CD4+ T细胞的影响。期间 2019 - 2020年，我们已经确定了C. gattii的未知生态来源，但没有针对Neoformans。