THE STRUCTURE OF HEPATITIS B ANTIGENS

这个项目的第一个目标是确定 乙肝病毒的表面蛋白，称为乙肝 表面抗原(HBs Ag)，并确定它们之间的关系 结构和功能既是病毒的基本蛋白又是 预防这种病毒疾病的重要宿主目标。乙肝表面抗原是 在乙肝病毒感染的正常过程中大量产生， 被广泛利用的事实：乙肝表面抗原是 乙肝病毒感染的诊断及其作为当前疫苗的应用 乙肝病毒。乙肝表面抗原由一组三种蛋白质组成，称为 S、M和L蛋白，每一种都以两种形式出现，原因是 进一步的翻译后修改。这些项目的结构将是 从自然感染中分离出蛋白质后确定的 人血浆，或随后通过克隆表达相关蛋白 真核或原核表达载体中的病毒DNA，使用 物理(圆二色谱、FTIR、质谱学、 超速离心)，化学(埃德曼降解，羧基肽酶 消化、还原和烷基化)和免疫学(单抗 抗体结合研究、免疫原性研究)技术。这个 这些蛋白中的每一种作为细胞受体结合蛋白的功能 并对聚合白蛋白进行检测。黄曲霉毒素的抗原性 这些蛋白质将通过定点突变、化学方法进行检测 修饰，使用抗合成肽和单抗。 这个项目的第二个目标是利用这些信息 从上述研究中获得，以确定特定的抗原域 用于掺入新型嵌合体的表面蛋白(S、M和L) 含有霍乱B毒素亚单位的蛋白质作为 潜在的抗乙肝病毒口服免疫原。这将通过以下方式完成 合成的DNA与霍乱B亚单位基因融合，并通过 合适的原核表达载体。

The first goal of this project is to determine the structures of the surface proteins of the hepatitis B virus, referred to as the hepatitis B surface antigen (HBsAg), and to determine the relationship between their structures and functions both as essential viral proteins and as the important host targets for prevention of the viral disease. HBsAg is produced in large amounts during the normal course of HBV infection, a fact which has been extensively exploited: HBsAg serves as the basis for the diagnosis of HBV infection and also as the current vaccine against HBV. HBsAg consists of a "nested" set of three proteins, referred to as the S, M, and L proteins, each of which occurs in two forms due to further post-translational modifications. The structure of these will be determined following isolation of the protein from naturally infected human plasma, or following expression of the relevant protein by cloned viral DNA in eukaryotic or prokaryotic expression vectors, using a combination of physical (circular dichroism, FTIR, mass spectrometry, ultracentrifugation), chemical (Edman degradation, carboxypeptidase digestion, reduction and alkylation), and immunological (monoclonal antibody binding studies, studies of immunogenicity) techniques. The function of each of these proteins as binding proteins to cell receptors and polymerized albumin will be examined. The antigenic activity of these proteins will be examined by site specific mutagenesis, chemical modification, use of anti- synthetic peptide and monoclonal antibodies. The second goal of this project will be to utilize the information gained from the above studies to identify specific antigenic domains of the surface proteins (S,M, and L) for incorporation into novel chimeric proteins containing the cholera B toxin subunit for investigation as a potential oral immunogen against HBV. This will be done utilizing synthetic DNA fused to the Cholera B subunit gene, and expression by appropriate prokaryotic expression vectors.