Development of Preventative and Therapeutic HCV Vaccines

描述（由申请人提供）：本申请的总体目标是开发丙型肝炎病毒（HCV）特异性免疫原，可作为预防和/或治疗性疫苗，用于预防或治疗慢性HCV感染。提出了两种一般的非排他性方法。在第一种方法（Specific Aim 1）中，我们建议开发一种预防性丙型肝炎疫苗，旨在诱导丙型肝炎病毒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平台能够容纳多种插入的B细胞和CD4 + T细胞表位，并引发针对插入的B细胞表位的极高水平的抗体和引物插入特异性CD4 v T细胞。三种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hvr1 E2表位；(b) E2高度可变的HVR1区域的一致序列，这将解决HCV的遗传变异性问题；(c) HVR1区域内存在保守的“框架基序”。将对E2- WHcAg杂交颗粒进行蛋白表达、组装能力、E. coil表达系统产量、抗原性和免疫原性等方面的优化。由于针对HCV抗原，特别是非结构3 （NS3）蛋白的强烈T细胞反应（CD4 vand cd8v）与急性和慢性HCV感染的病毒清除有关，我们的第二种方法将旨在开发一种NS3/ 4a特异性DNA候选疫苗（Specific Aim 2）。NS3蛋白是高度保守的，DNA疫苗的一个优势是能够诱导CD4 v Th细胞和CD8 v CTL以及抗体。我们发现NS3/ 4a基因比广泛使用的NS3基因更有效地引发免疫反应。预计NS3/4A DNA疫苗可单独或与E2-WHcAg杂交颗粒联合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.