Virus-like-particle (VLP) vaccine for chicken infectious anemia.

The human population relies on food animals as a major source of high quality protein. Maintaining the health of these animals is of critical importance to good human nutrition worldwide. Chicken anemia virus (CAV) is an important immunosuppressive pathogen of poultry. We are proposing to improve vaccines and diagnostics for this pathogen to improve animal health. Chicken infectious anemia (CIA) is the disease caused by CAV, a ubiquitous virus found in all poultry producing regions worldwide. CAV has been controlled by vaccinating breeder flocks one time with a live attenuated vaccine at about 12 weeks of age. The resulting maternal immunity is transferred to chicks and protects them against CAV during the critical early development of their immune systems. However, the immunity to CAV in the breeder flock declines over time, leaving chicks vulnerable to infection. A vaccine is needed that can be used multiple times to create a longer lasting immunity to CAV in breeder flocks. Although CAV often causes only a subclinical disease in young chicks, the resulting infection results in reduced growth rate, poor feed efficiency, lower weight uniformity and most importantly immune suppression that leaves chicks susceptible to secondary and opportunistic infections.Vaccine companies are currently producing live CAV vaccines in cell culture or embryonated chicken eggs. In addition to being expensive and time consuming, the quantity of antigen produced through this method is highly variable. In the poultry vaccine market, profit margins are very tight. Producing CAV vaccine using conventional methods is not only expensive but is a bottleneck in the production of these vaccines that can cause an inability to meet market demand. CAV vaccine manufacturers have also had problems with CAV contamination in their other vaccines. This has caused some very expensive decontamination efforts and loss of the contaminated vaccine lots. Our proposal to produce a CAV vaccine using genetic engineering is one solution to these problems. No infectious CAV is ever used in our system and production quality and quantity is improved.