δ因子是1977年首次在意大利由Rizzetto等发现并报道的。近几年来,有关这方面的研究和进展很快,现综述如下。δ因子的性质从急性感染的黑猩猩及人血中已经分离出了δ因子。δ因子直径为35—37nm,由δ抗原形成核心,外包有HBsAg膜而组成,故被认为是一缺陷因子。δ遗传基因是小分子量的RNA(5.5×10~5道尔顿,1.75kb),与宿主rRNA The δ-factor was first discovered and reported by Rizzetto et al. in Italy in 1977. In recent years, the research and progress in this area are fast and are summarized as follows. The nature of the delta factor The delta factor has been isolated from acutely infected chimpanzees and human blood. The δ factor is 35-37 nm in diameter and is composed of δ antigen and is composed of HBsAg film and is therefore considered a defect factor. The delta gene is a small molecular weight RNA (5.5x10-5 Daltons, 1.75 kb) that binds to the host rRNA