The Melanocortin-4 Receptor in Human Obesity

描述（由申请人提供）：在美国，丙型肝炎病毒（HCV）是进行性肝炎、肝硬化和肝细胞癌的主要原因。了解使大约15%的人能够清除急性丙型肝炎的免疫类型是开发疫苗的关键。对黑猩猩和人类的探索性研究表明，靶向多种HCV蛋白的T细胞似乎是清除HCV的必要条件。为了更好地了解与保护相关的免疫类型，需要仔细研究成功的反应。注射吸毒者的新丙型肝炎病毒感染率最高，但通常许多人无法随访。在一个由200多名注射者组成的当地流行病学队列中，发现并随访了HCV新发感染率很高（28%/人/年）。这现在允许对急性丙型肝炎患者进行前瞻性研究。在这个项目中，Aim 1建议从诊断的角度（基于转化为HCV RNA或抗体阳性）前瞻性地检查HCV特异性抗体和T细胞反应。结合淋巴细胞增殖、细胞内细胞因子染色和ELISpot检测HCV蛋白靶点和CD4+ T细胞和CD8+ T细胞应答的活力。将进行定性和定量抗体分析，扩大HCV特异性CTL，检测它们的基因库，精确定位它们的表位和HLA限制。将合成一些HLA/肽表位的MHC I类四聚体，以便对溶解者和进展者的CTL库进行更高分辨率的比较。假设肽表位内的进化导致病毒从CTL中逃逸。这种免疫逃逸模型将在Aim 2中进行测试，因为CTL表位变体将在CTL分析中进行测序、合成和测试。如果表位的变异范围仍能被CTL识别，那么它将构成合乎逻辑的疫苗成分。最近的实验证明了hcv特异性CTL表达抑制和激活受体（NKR）阵列。NKR配体库取决于人的HLA类型，这表明NKR+ CTL可能受到肝脏中配体相互作用的可变调节。这将在Aim 3中进行测试。总的来说，这项研究将为HCV免疫保护机制提供独特的见解。它还将为疫苗设计奠定基础。

DESCRIPTION (provided by applicant): In the US, hepatitis C virus (HCV) is the leading cause of progressive hepatitis, cirrhosis and liver cell cancer. Understanding the type of immunity that allows approximately 15% people to clear acute hepatitis C holds the key to developing a vaccine. Exploratory studies in chimpanzee and humans show that T cells targeting multiple HCV proteins seem necessary for HCV clearance. To better understand the type of immunity that correlates with protection, careful study of successful responses will be required. Injection drug users have the highest rates of new HCV infection but typically many get lost to follow-up. In a local epidemiological cohort of over 200 injectors a high rate (28%/person/year) of new HCV infections has been identified and followed up. This now permits prospective study of people with acute hepatitis C. In this project, Aim 1 proposes to prospectively examine HCV-specific antibody and T cell responses from the point of diagnosis (based on conversion to HCV RNA or antibody positivity). The HCV protein targets and vigor of CD4+ T cell and CD8+ T cell responses will be determined by combining lymphoproliferation, intracellular cytokine staining, and ELISpot assays. Qualitative and quantitative antibody analysis will be conducted and CTL specific for HCV will be expanded, their repertoires examined and their epitopes and HLA restriction precisely mapped. MHC class I tetramers of some HLA/peptide epitopes will be synthesized for higher resolution comparison of CTL repertoires in resolvers and progressors. Evolution within peptide epitopes is hypothesized to result in viral escape from CTL. This model of immune escape will be tested in Aim 2, as CTL epitope variants are sequenced, synthesized and tested in CTL assays. An epitope whose ange of variants can still be recognized by CTL would constitute a logical vaccine component. Recent experiments have demonstrated expression of arrays of inhibitory and activating receptors (NKR) by HCV-specific CTL. The NKR ligand repertoire depends on the person's HLA type suggesting that NKR+ CTL may be variably regulated depending on ligand interaction in the liver. This will be tested in Aim 3. Overall this investigation will provide unique insights into protective mechanisms of immunity against HCV. It will also lay a foundation for vaccine design.