Ad3.0: Studying infection biology of the natural diversity of adenoviruses and implications for gene-based medicine

• Applicant: Professorin Anja Ehrhardt, Ph.D.
• Subject Area: Virology
• Term: from 2011 to 2023
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 192749484

Adenoviruses are widely used in therapeutic and vaccination studies or simply as a tool for efficient DNA transfer. Over the recent years we have focused on analyzing the fate and stability of adenoviral genomes after infection of mammalian cells. However, besides the fate of the adenoviral DNA molecule the capsid also plays a key role during cellular transduction with adenovirus. The major capsid components are represented by the fiber, penton and hexon proteins. Until recently it was believed that the adenovirus fiber and penton proteins are predominantly involved in virus tropism. This paradigm was changed when it was found that also the hypervariable regions (HVRs) of the hexon, besides being a dominant immune-modulator, also play a key role in tropism. However, until now only a limited number of adenoviruses modified within the HVRs were generated due to the lack of a sufficient system for genetic manipulation. In general the characterization of the 53 identified human adenovirus serotypes with their distinct properties is hindered due to the absence of an efficient genetic system for cloning and modification of adenovirus genomes. Therefore, for the first time this proposal aims at utilizing a systematic approach to genetically modify adenovirus. Based on our established bacterial artificial chromosome (BAC)-cloning technology, we have begun to generate a set of recombinant adenoviruses. In this proposal we plan to (1) clone hexon-chimeric sequences from the entire spectrum of human adenovirus serotypes into a recombinant adenoviral vector. To ensure integrity of the hexon and for direct comparison we also plan for the first time to subclone the complete spectrum of wild-type adenovirus genome as BACs. Reconstituted adenoviruses will be (2) evaluated in vitro including the neutralizing capacity of human sera and (3) the tropism and innate immune responses will be analyzed in vivo. With this approach we will gain pivotal information about factors influencing tropism of adenoviruses. In concert with subcloning of complete adenovirus genomes derived from various serotypes, this approach will pave the way towards design of novel therapeutic adenoviruses including our established gutless adenovirus technology.

• DFG Programme: Research Grants