HCV 6a所致的慢性丙型肝炎在华南等地呈快速增长趋势。我们已经建立了HCV 6a患者研究队列和标本库，构建了多种HCV6a结构基因和非结构基因质粒。HCV不同的基因型具有明显不同的复制与抗病毒应答特点，其关键序列和机制是什么？本项目利用JFH1（2a）可高效细胞培养的特性，以JFH1序列为骨架，用6a的结构基因和非结构基因分别置换JFH1相应基因区，构建两种6a/2a嵌合体质粒，转染Huh7.5细胞，用促进复制相关的适应性突变发生与保持感染性相关E1/E2不变的策略，建立HCV 6a全基因细胞培养系统。随后建立6a/2a/1b 三种亚型的比较分析系统，分析不同基因型以及临床上不同应答结局病人HCV NS5A/C-E2等关键序列对复制和抗病毒应答的影响；阐明华南高流行HCV 6a病毒株的生物学特点、相关免疫学特征，同时为疫苗研制、抗病毒药物的评价和筛选等提供分析平台。

The number of chronic hepatitis C(CHC) patients infected with HCV genotype 6a is rapidly increasing in Southern China and elsewhere. We have established a cohort study of CHC patients infected by HCV 6a and the database of samples. The various recombinant plasmids contained structural genes or nonstructural genes of HCV 6a were constructed. Different HCV genotypes with the different characteristics of replication and responses to the antiviral therapies have fully reported. What are the key viral sequence and its mechanism? We will use the structure-gene and nonstructure-gene of genotype 6a to replace the related regions of JFH1 (2a) that showed robust replication ability in cell culture system, and to construct two 6a/2a chimeras. After transfecting into Huh7.5 cell lines with the RNA from the chimeras, obtaining chimera strains containing cell culture-adaptive mutations, we will further establish the whole genomic cell culture system of HCV 6a with the strategy of promoting the replication enhancing mutations and stablizing the hypervariable regions of E1/E2. With these cell culture systems, the mechanism of HCV NS5A/C-E2 regions influencing on viral replication and host immunological response will be elucidated. The study will provide experimental and theoretical evidences for the analysis of biological features, immunological characteristics, and contribute to the vaccine development and screening new drug against HCV 6a infection.