The principal objective of this proposal is to demonstrate the applicability of the new technology based on the expression of recombinant viral empty capsids in insect cells using the baculovirus expression system (BEVS) for the production of vaccines on an industrial scale. The production of empty particles that mimic perfectly the original viral structures is becoming more and more popular in the literature. Most, if not all, of these empty particles have shown optimal immunological properties that make them suitable candidates for vaccine production. Unfortunately, the applicability of this technology has been hampered by several factors, including: lack of knowledge of the BEVS culture and recovery conditions for medium and large scale in insect cells, the cost and organization of the experiments required for showing the efficacy and potency of the antigens in field conditions, and, finally, the burden and complexity of the regulatory affairs to get the registration of a recombinant vaccine. In this proposal we address the first two problems using the production of porcine parvovirus empty particles as a model. PPV is responsible for a major reproductive disease in pigs, which is usually controlled by vaccination. This product has been successfully expressed in the baculovirus system but need application of medium to large scale culture technology to demonstrate that they have real potential as cost-effective recombinant vaccines. It is anticipated that knowledge derived from the study of this target will also be useful for the production of other proteins and vaccines. The problem will be studied through several work packages. The first package will address the issue of optimising expression of the recombinant particles, to maximize protein production.
Optimal growth conditions for the insect cells will be determined and the requirements for efficient infection by the recombinant baculovirus will be established. Analyses of the infection process including the quantity and characteristics of the expressed products will be performed. Successive steps will study the optimal conditions for downstream processing, vaccine formulation and dose-response experiments to demonstrate the efficacy and potency of the vaccine. Safety of these vaccines will be a major issue in our proposal. To this end, several experiments on different animal species will be carried out to study the effect of several parameters such as age, sex, etc. in the response to the vaccine. Finally, large immunization trials in field conditions are planned along the proposal time.
The project is structured so that each objective can be achieved largely independently, which permit consistent progress throughout the contract. The current levels of expression do allow the production of sufficient material to perform the first efficacy, potency and safety experiments immediately after starting the project. The data, collected by the consortium of the project, will determine the key parameters in all aspects of the vaccine production and formulation, which will lead to an optimised protein production for both routine laboratory work and industrial scale up level. The information obtained in this project will be immediately applied to other coming-up vaccines in human and animal health.
Funding SchemeCSC - Cost-sharing contracts
8200 AB Lelystad