ADENOVIRIDAE

Adenoviruses were first identified in 1953 as the causative agents of the common cold. In 1977, Frank Graham developed a cell line which enabled the first production of recombinant adenoviruses as gene transfer agents that required no additional assistance. Adenoviral virions (i.e. a complete, infective viral particle consisting of genetic material surrounded by a protein shell or capsid) are icosahedral in shape, 70-90nm in diameter, and are not enveloped. The majority of the viral capsid consists of the three proteins: penton based (involved in cell internalization and receptor binding), fiber, and hexon. The viral genome consists of a single double stranded DNA molecule 36-38 kilobases long. All recombinant adenoviral vectors have deletion of the E1A region which is the first gene transcribed upon host cell nuclear entry and essential for viral replication. Termed "replication-deficient," these vectors can infect a cell only once and with no viral propagation. As a result, the..