Dendritic cell targeted hepatitis c virus immunotherapy

描述（由申请人提供）： 丙型肝炎是世界上最流行和最阴险的疾病之一。不到41%的患者对目前的治疗有反应，很大一部分患者不适合接受治疗。因此，迫切需要新的治疗策略。丙型肝炎病毒（HCV）的清除与HCV特异性CD 4 + T细胞的水平相关，并且已经在免疫显性CD 4 + T细胞表位中鉴定出病毒逃逸突变。这些结果表明，旨在增加和扩大HCV特异性CD 4 + T细胞的免疫疗法可以提供一种新的治疗方法。树突状细胞（Dendritic cells，DCs）是最重要的一类专职抗原提呈细胞，具有诱导体液和细胞免疫应答的能力。这些细胞准备捕获病原体，迁移到引流淋巴结，并选择抗原特异性CD 4 + T细胞来调节T、B和NK细胞，所有这些都可能有助于保护性免疫。该提案的目的是开发一种新的疫苗策略，将HCV非结构蛋白3（NS 3）直接靶向DC亚群，例如，朗格汉斯细胞（LC）。最近，我们表明可以通过用GM-CSF+ IL 15培养单核细胞来产生LC。此类LC在体内诱导显著的T细胞活化。此外，我们已经从噬菌体展示肽库中产生了特异性结合LC或间质DC的肽。我们假设直接将NS 3靶向DC将增加特异性免疫应答的水平和持续时间。因此，我们将通过将NS 3偶联或融合到DC特异性肽来将其靶向DC。我们进一步假设，NS 3可以进行结构修饰，以消除免疫显性表位，因此招募新的T细胞抗HCV。具体目标是：1）通过分析人源化SCID小鼠中的T细胞增殖/活化来确定特异性靶向DC亚群的NS 3是否增强针对HCV的特异性免疫应答;和2）通过工程化HCV NS 3的三维结构来增强产生IFN 3 γ的NS 3特异性CD 4 + T细胞的发育。将探索加载DC亚群的替代模式，包括通过表达和分泌DC靶向NS 3的重组乳杆菌属。无针和无毒的免疫疗法将为目前没有丙型肝炎的患者提供治疗。

DESCRIPTION (provided by applicant): Hepatitis C is one of the worlds most pandemic and insidious diseases. Less than 41% of patients respond to the current treatment, and a large fraction is ineligible for therapy. Thus, there is an urgent need for new therapeutic strategies. Clearance of hepatitis C virus (HCV) is correlated with the level of HCV-specific CD4+ T cells, and viral escape mutations have been identified in immunodominant CD4+ T-cell epitopes. These results suggest that an immunotherapy designed to increase and broaden HCV-specific CD4+ T cells could provide a new therapeutic approach. Dendritic cells (DCs), the most important class of professional antigen presenting cells, possess the ability to elicit both humoral and cellular immune responses. These cells are poised to capture pathogens, migrate to draining lymph nodes, and select antigen-specific CD4+ T cells to regulate T, B, and NK cells, all of which may contribute to protective immunity. The objective of this proposal is to develop a novel vaccine strategy targeting the HCV nonstructural protein 3 (NS3) directly to DC subsets, e.g., Langerhans Cells (LCs). Recently we showed that LCs can be generated by culturing monocytes with GM-CSF+IL15. Such LCs induce significant T-cell activation in vivo. Furthermore, we have generated peptides that bind specifically to LCs or interstitial DCs from a phage display peptide library. We hypothesize that targeting NS3 directly to DCs will increase the level and duration of specific immune responses. Thus, we will target NS3 to DCs by coupling or fusing it to DC-specific peptides. We further hypothesize that NS3 can be structurally modified in order to eliminate the immunodominant epitopes and therefore recruit new T cells against HCV. Specific aims are: 1) To determine whether targeting NS3 specifically to DC subsets enhances specific immune responses against HCV by analyzing T-cell proliferation/activation in humanized SCID mice; and 2) To augment the development of IFN3 gamma-producing NS3-specific CD4+ T cells by engineering the three-dimensional structure of HCV NS3. Alternative modes of loading DC subsets will be explored, including via recombinant Lactobacillus sp. that express and secrete DC-targeted NS3. A needle-less and non-toxic immunotherapy would provide a treatment for hepatitis C patients who currently have none.