Adenovirus as a carrier for the development of influenza virus-free avian influenza vaccines

Abstract

A long-sought goal during the battle against avian influenza is to develop a new generation of vaccines capable of mass immunizing humans as well as poultry (the major source of avian influenza for human infections) in a timely manner. Although administration of the currently licensed influenza vaccine is effective in eliciting protective immunity against seasonal influenza, this approach is associated with a number of insurmountable problems for preventing an avian influenza pandemic. Many of the hurdles may be eliminated by developing new avian influenza vaccines that do not require the propagation of an influenza virus during vaccine production. Replication-competent adenovirus-free adenovirus vectors hold promise as a carrier for influenza virus-free avian influenza vaccines owing to their safety profile and rapid manufacture using cultured suspension cells in a serum-free medium. Simple and efficient mass-immunization protocols, including nasal spray for people and automated in ovo vaccination for poultry, convey another advantage for this class of vaccines. In contrast to parenteral injection of adenovirus vector, the potency of adenovirus-vectored nasal vaccine is not appreciably interfered by pre-existing immunity to adenovirus.

Keywords::

• adenovirus
• AdHigh
• avian influenza
• influenza virus-free influenza vaccine
• in ovo vaccine
• mass immunization
• nasal vaccine
• RCA

Acknowledgements

The authors thank the University of Alabama at Birmingham for providing the animal facility and performing a human clinical trial on an adenovirus-vectored avian influenza (H5N1) vaccine; Southern Research Institute for performing some of the assays and animal challenge studies in their BSL-3⁺ facility; Southeast Poultry Research Laboratory for challenging chickens with highly pathogenic avian influenza viruses in their BSL-3⁺ facility; and Southern Drug Research for performing a human clinical trial on an adenovirus-vectored influenza (H1N1) vaccine.

Financial & competing interests disclosure

The authors at Vaxin Inc. and Auburn University are shareholders of Vaxin Inc. and inventors on patents pertaining to adenovirus-vectored vaccines. The National Institutes of Health and the US Navy provided grant support. The authors have no other relevant affiliations or financial involvement with any organization or entity with a financial interest in or financial conflict with the subject matter or materials discussed in the manuscript apart from those disclosed.

No writing assistance was utilized in the production of this manuscript.