| 摘要 |
The principle of this invention is to produce mini-Ad vectors using packaging-attenuated and replication-defective helper Ad and an E1-complementing Ad helper cell line. Since the essential cis-acting elements for Ad DNA replication and packaging are located at the ends of the viral genome (ITRs plus the packaging signal, less than 1 kb), the backbone of the mini-Ad vectors is trimmed down to contain only the essential <i>cis</i>-elements. The remainder of the Ad genome is to be replaced by non-viral DNA for gene transfer, retention, and expression. The capacity of the mini-Ad vectors may be up to 36 kb. The viral proteins required for DNA replication and encapsidation of the mini-Ad vectors are designed to be provided <i>in trans</i> from the helper Ad (<i>trans</i>)-complementation) and the helper cell line. In order to generate relatively pure preparations of the mini-Ad virions, packaging of the helper Ad genome is controlled by selective attenuation of the packaging signal while that of the mini-Ad vector genome proceeds normally. In the absence of mini-Ad vector genome, the helper Ad does replicate and is propagated in an inefficient manner. In this system, the Ad helper cell line is necessary for the E1-complementation of the helper virus and may also provide other functions for packaging attenuation of the helper viral genome and enhancement of mini-Ad vector replication. If the preparation of mini-Ad vectors is not sufficiently pure, biochemical or other physical methods will be utilized to achieve further purification. |
