Innate immune mechanisms in dengue infection

描述（由申请人提供）：关于登革热病毒感染的最令人困惑的问题之一是，虽然一种血清型的原发性感染导致对同一血清型的长期保护，但异源血清型的感染导致从轻微到严重的广泛疾病，在某些情况下甚至致命。造成这一结果的机制尚不清楚，并对生产有效的登革热疫苗提出了重大挑战，因为这种疫苗实际上可能加剧严重疾病。我们的实验室一直在研究登革热（DF）和登革出血热（DHF）患者对登革热病毒的急性反应，试图描述在流行人群中区分登革出血热和登革出血热的生物标志物。在此过程中，我们的实验室记录了以下内容：A)登革热感染早期（1-3天）；这些患者的血浆包含许多细胞因子和趋化因子,我们提交驱动记忆B细胞的动员发展成等离子体爆炸并代表> 50%的B细胞在血液B)等离子体爆炸高度易感细胞凋亡的因素(7 - 10天)血清晚期病人和/或他们的交互与Fas-L NK细胞表达c)有显著增加的频率plamacytoid树突状细胞(pDC),表达不成熟表型d)在这些患者中存在针对异源登革热病毒的沉默记忆B细胞反应。基于这些初步发现，我们的实验室制定了一系列问题，旨在更详细地确定急性登革热感染期间发生的免疫事件链，目的是确定与疾病严重程度相关的事件。因此,本提案的目标是开展详细的研究，a)急性感染期间登革热患者血清中存在的趋化因子/细胞因子水平，并确定血浆母细胞上的归巢标记和轻度无症状v/s严重疾病的相关性；b)试图确定导致血浆母细胞凋亡增强的机制；c)检查KIR/MHC多态性之间的关系，这些多态性有助于NK细胞和细胞之间相互作用的质量单核细胞和树突状细胞（DC）和d)与疾病严重程度相关的单核细胞/DC的表型和功能异质性的研究。我们已经组建了一支由免疫学家、病毒学家和儿科登革热临床医生组成的优秀团队，他们在登革热病毒疾病方面有着长期的工作记录，以解决所概述的每一个具体目标，并认为这些研究的结果不仅有助于了解登革热感染的发病机制，还可能为有效的疫苗配方提供线索。

DESCRIPTION (provided by applicant): One of the most perplexing issues with regards to dengue virus infection is the finding that whereas primary infection with one serotype leads to long term protection against the same serotype, infection with a heterologous serotype leads to a wide spectrum of illness ranging from mild to severe and in some cases fatal. The mechanisms for this outcome are far from clear and provide for a major challenge to produce an effective dengue vaccine since the potential exists that the vaccine may in fact potentiate severe disease. Our lab has been studying the acute response to dengue virus in patients with dengue fever (DF) and dengue hemorrhagic fever (DHF) in attempts to delineate biological markers that can distinguish DF from DHF in an endemic population. During this process our lab has documented the following: a) early (day 1-3) during dengue infection, the plasma of these patients contain a number of cytokines and chemokines that we submit drive the mobilization of memory B cells which develop into plasma blasts and represent >50% of the B cells in the blood b) the plasma blasts are highly susceptible to apoptosis by factors in the late (day 7-10) sera of these patients and/or by their interaction with Fas-L expressing NK cells c) there is a marked increase in the frequencies of plamacytoid dendritic cells (pDC's) which express immature phenotype d) there is a muted memory B cell response against the heterologous dengue virus in these patients. Based on these preliminary findings, our lab has formulated a series of questions, which are aimed at defining in more detail the chain of immunological events that occur during acute dengue infection with the aim to define the events that are associated with disease severity. Thus, the objectives of this proposal are to carry out detailed studies of a) levels of the chemokines/cytokines that are present in the sera of dengue patients during acute infection and identify homing markers on the plasma blasts and correlate mild asymptomatic v/s severe disease b) attempt to define the mechanisms that lead to enhanced apoptosis of the plasma blasts c) examine the relationships between KIR/MHC polymorphisms that contribute to the quality of interactions between NK cell and monocytes and dendritic cells (DC's) and d) studies of the phenotypic and functional heterogeneity of monocytes/DC's that correlates with disease severity. We have assembled an outstanding team of immunologists, virologists and pediatric dengue clinicians with a long track record of working on dengue viral disease to address each of the specific aims outlined and submit that the results from these studies will not only contribute to the understanding of the pathogenesis of dengue infection but may also provide clues to effective vaccine formulation.