Pro-Apoptotic BCG as an HCV vaccine vector

描述（由申请人提供）：丙型肝炎病毒和结核分枝杆菌都是非常成功的病原体，它们之间的共同点是宿主细胞免疫反应在控制感染方面非常重要。我们的研究小组对世界上最常用的卡介苗进行了新的基因修饰，以消除免疫逃避基因。这种被称为“促凋亡卡介苗”的改良卡介苗在易感小鼠品系中显示出强有力的免疫应答。与亲本卡介苗相比，新疫苗在对疫苗接种的初次应答中引起t细胞产生更多的IL-2，在再次应答中引起更快的召回反应。我们应用R21的目标是将HCV抗原引入这些修饰的卡介苗株中，以开发能够引发有效细胞免疫反应的结核-HCV混合疫苗。1)构建表达HCV抗原的重组促凋亡卡介苗（rpaBCG）疫苗。2)验证以前从慢性或缓解型HCV感染的黑猩猩身上分离的T细胞克隆和外周血单个核细胞对疫苗表达的HCV抗原的识别。3)评价这些疫苗在HLA - i类转基因小鼠中的免疫原性。如果成功，我们未来的目标将包括更大规模的小鼠研究和小型灵长类动物研究，以评估含有不同HCV插入物的疫苗的免疫原性。促凋亡卡介苗作为抗原递送平台的优势在于，尽管经过修饰使其更弱，但它能够引发比卡介苗更强的免疫反应，这也应该在人类已经很好的安全性基础上得到改善。本提案将利用每位研究者的独特专业知识。我们计划在一种高免疫原性和安全的载体中表达HCV抗原，这将有助于这种疫苗从实验室转移到临床。项目简介：丙型肝炎病毒目前感染全球1.7亿人，是肝硬化的主要原因。我们的目标是将丙型肝炎蛋白纳入一种广泛使用的安全结核病疫苗的改良版本，我们称之为“促凋亡卡介苗”。我们改良的卡介苗在小鼠模型中比原卡介苗株引起更好的免疫反应，并且作为促凋亡的BCG- hcv联合疫苗可以迅速从小鼠试验转移到人类试验。

DESCRIPTION (provided by applicant): Hepatitis C virus and Mycobacterium tuberculosis are each immensely successful pathogens, with the common thread between them that host cellular immune responses are extremely important in controlling infection. Our group has made novel genetic modifications to eliminate immune-evasive genes in the most commonly administered worldwide vaccine, BCG. The modified BCG vaccine, called "pro-apoptotic BCG", demonstrates potent immune responses in susceptible mouse strains. Compared to the parent BCG vaccine, the new vaccine elicits greater IL-2 production by T-cells during the primary response to vaccination and quicker recall responses during re-challenge. Our goal with this R21 application is to introduce HCV antigens into these modified BCG strains to develop a hybrid TB-HCV vaccine capable of eliciting potent cellular immune responses. We will 1) Construct recombinant pro-apoptotic BCG (rpaBCG) vaccines that express HCV antigens. 2) Verify recognition of vaccine-expressed HCV antigens by T cell clones and peripheral blood mononuclear cells previously isolated from chimpanzees with chronic or resolved HCV infection. 3) Evaluate immunogenicity of these vaccines in HLA Class I-transgenic mice. If successful, our future goals will include larger scale mouse studies, and small primate studies to evaluate the immunogenicity of vaccines with different HCV inserts. The advantage of pro-apoptotic BCG as a platform for antigen delivery is its ability to elicit stronger immune responses than BCG despite modifications which make it more attenuated, which should also improve upon an already good safety profile in humans. This proposal will take advantage of the unique expertise of each investigator. Our plan to express HCV antigens in a highly immunogenic and safe vector will facilitate the migration of this vaccine from the bench to the clinic. Project Narrative: Hepatitis C virus currently infects 170 million people worldwide, and is a leading cause of cirrhosis of the liver. Our goal is to incorporate Hepatitis C proteins in a modified version of a widely used and safe tuberculosis vaccine, which we call "pro-apoptotic BCG". Our modified BCG vaccine elicits better immune responses in a mouse model than the original BCG strain, and as a combined pro-apoptotic BCG-HCV vaccine could move quickly from testing in mice to humans.