Development of Preventative and Therapeutic HCV Vaccines

描述(申请人提供)：这项建议的总体目标是开发丙型肝炎病毒(丙型肝炎病毒)特异性免疫原，可用作预防或治疗慢性丙型肝炎病毒感染的预防性和/或治疗性疫苗。提出了两种一般的非排他性方法。在第一种方法(特定目标1)中，我们建议开发一种预防性丙型肝炎疫苗，旨在诱导针对丙型肝炎病毒E2蛋白的中和抗体。为此，我们开发了土拨鼠肝炎核心蛋白(WHcAg)作为颗粒疫苗载体平台。WHcAg平台能够容纳各种插入的B细胞和CD4T细胞表位，并诱导出针对插入的B细胞表位和质粒插入特异性的CD4v T细胞的极高水平的抗体。三类E2特异性中和B细胞表位将被插入到WHcAg疫苗平台中：(A)我们已经确定的高度保守的非HVR1E2表位；(B)来自E2的高度可变的hvr1区域的共识序列，它将解决丙型肝炎病毒的遗传变异性问题；以及(C)存在于hvr1区域内的保守的“框架基序”。E2-WHcAg杂化颗粒将在蛋白质表达、组装能力、在E.CoIL表达系统中的得率、抗原性和免疫原性方面进行优化。由于针对丙型肝炎病毒抗原，特别是非结构蛋白3(NS3)的强大T细胞反应(CD4v和CD8v)与急、慢性丙型肝炎病毒的清除有关，我们的第二个方法将致力于开发一种针对NS3/4A的特异性DNA疫苗候选(特定目标2)。NS3蛋白高度保守，DNA疫苗的一个优势是能够诱导CD4v Th细胞和CD8vCTL以及抗体。我们发现，NS3/4A基因比广泛使用的NS3基因诱导的免疫反应明显更有效。预计NS3/4A DNA疫苗可单独或与E2-WHcAg杂化颗粒一起用于预防或治疗应用。

DESCRIPTION (provided by applicant): The overall objective of this proposal is to develop hepatitis C virus (HCV)-specific immunogens that may be useful as prophylactic and/or therapeutic vaccines for the prevention or treatment of chronic HCV infection. Two general nonexclusive approaches are proposed. In the first approach (Specific Aim 1) we propose to develop a prophylactic HCV vaccine designed to elicit neutralizing antibodies to the HCV E2 protein. For this purpose we have developed the woodchuck hepatitis core protein (WHcAg) as a particulate vaccine carrier platform. The WHcAg platform is capable of accommodating a variety of inserted B cell and CD4 + T cell epitopes and elicits extremely high levels of antibodies to the inserted B cell epitopes and primes insert-specific CD4 v T cells. Three categories of E2-specific neutralizing B cell epitopes will be inserted into the WHcAg vaccine platform: (a) highly conserved, non-HVR1 E2 epitopes that we have identified; (b) consensus sequences derived from the highly variable HVR1 region of E2, which will address the problem of genetic variability of HCV; and (c) conserved "framework motifs" present within the HVR1 region. The E2- WHcAg hybrid particles will be optimized for protein expression, assembly competence, yield in the E. coil expression system, antigenicity and immunogenicity. Because strong T cell responses (both CD4 vand CD8 v) against HCV antigens and especially the nonstructural 3 (NS3) protein have been linked to viral clearance in acute and chronic HCV infection, our second approach will be aimed at developing a NS3/4A-specific DNA vaccine candidate (Specific Aim 2). The NS3 protein is highly conserved and an advantage of a DNA vaccine is the ability to elicit CD4 v Th cells and CD8 v CTL as well as antibody. We have found that a NS3/4A gene elicits significantly more efficient immune responses than the widely used NS3 gene. It is anticipated that a NS3/4A DNA vaccine may be used for prophylactic or therapeutic applications either alone or in combination with E2-WHcAg hybrid particles.