Development of next generation vaccine technology inducing rapid and strong immunity through targeted delivery of antigens to chicken immune cells

Safe and disease-free poultry production systems are crucial for maintaining food supplies to feed the increasing human population and to improve the livelihoods of farming communities. However, the biggest threat in the sustainable growth of farmed animal production is the emergence, re-emergence and continual prevalence of a multitude of infectious animal pathogens, such as avian influenza. Primarily, the control against these pathogens is achieved through vaccination. However, the effectiveness of most of the current vaccines is suboptimal, where they may only reduce manifestation of clinical disease and mortality, but infected animals continue to shed viruses resulting in a continual chain of infections to susceptible naïve and vaccinated animals. For example, despite the large-scale deployment of multiple doses of influenza vaccine to an individual bird, manifestation of disease continues in the form of endemic prevalence and farmers continue to bear debilitating losses with up to 100 percent flock mortality or loss of egg production along with the threat of zoonotic infections. Therefore, improvement of the current vaccines are required that produce stronger immunity and full protection against disease, together with a reduction in shedding of infectious virus from infected animals, preventing the endemic prevalence of these viruses in farmed animals. In this proposal, we plan to develop robust and effective vaccines that elicit strong and durable humoral and cellular immune responses against viral pathogens which cause severe economic losses in poultry industries. As a proof-of-principle, we have demonstrated that targeted delivery of antigens to chicken immune cells potentiate the antigen-specific immune responses in vaccinated chickens compared to the untargeted counterpart or the conventional killed virus vaccines. The targeted vaccines demonstrated a significantly faster and a significantly higher immune response. These studies therefore provided strong data to take this new vaccine technology from laboratory to the farm. To achieve this goal, we have established partnership with a commercial poultry vaccine producer "MSD Animal Health". Through this collaboration, we will investigate how our developed targeted antigen delivery vaccine (TADV) formulation can further be optimised to i) induce even more rapid immunity and provide more potent and broader immune responses against antigenic AIV variants infecting poultry in different geographic regions; ii) enhance the production and delivery methods in chickens using our well-established insect cell cultures and recombinant viral vector (herpesvirus of turkey) system. The result obtained from this proposed research would provide a novel next generation improved AIV vaccine and a platform for improvement of vaccine technology against other important livestock and human pathogens. Availability of these novel highly protective and cost-effective disease control tools and strategies should minimise the impact of infectious diseases on farm animals, and offer substantial indirect economic, public health, environmental and social benefits to the UK and rest of the world.