Development of a new inactivated porcine reproductive and respiratory syndrome virus (PRRSV) vaccine

Porcine reproductive and respiratory syndrome virus (PRRSV) is responsible for reproduction disorders in sows, which leads to tremendous economic losses in the pig industry worldwide. It is also associated with porcine respiratory disease complex (PRDC), which supports massive use of antibiotics. Although several modified live virus (MLV) and killed virus (KV) vaccines are on the market, PRRSV remains difficult to control in the field. The major aim of this thesis was to develop a new experimental inactivated PRRSV vaccine. The different processes to develop a vaccine are virus production, virus inactivation or attenuation and vaccine formulation. In this thesis, the virus production and the virus inactivation of PRRSV were optimized to develop an efficient KV vaccine. The first section of chapter 1 gives an introduction on PRRSV, more particular its history, classification, virus structure, genomic organization, viral proteins, replication cycle, clinical signs, pathogenesis, innate and adaptive immune response to PRRSV and the available vaccines. A second section of chapter 1 gives an overview of different viral inactivation procedures, such as cross-linkers (formaldehyde, glutaraldehyde and AT-2), denaturing agents (pH and temperature), irradiation (ultraviolet (UV) and gamma irradiation) and alkylating agents (binary ethyleneimine (BEI)), and their effect on viruses