Demonstrate the Safety and Efficacy of a PRRS-RP Vaccine Candidate

Porcine Reproductive and Respiratory Syndrome Virus (PRRSV) costs the swine industry approximately $560M annually through reproductive loss in mature females and respiratory disease in growing pigs. There is a need for new vaccines for PRRSV to battle the strain evolution and heterogeneity of this RNA virus. Currently the only available US commercial product is a Modified Live Virus (MLV) from BI-Vetmedica. Use of a MLV PRRSV vaccine poses the risks of reversion to virulence and recombination with field viruses and thus is not compatible with an eradication program. Traditional killed autogenous vaccines for PRRSV are also available but are slow to produce / prepare (up to 3 months) and because they contain the whole virus they are not compatible with differential diagnostic tests. In a recent meeting at the University of Illinois attended by renowed scientists and chaired/organized by Dan Rock a white paper was produced which concluded that MLV and inactivated whole virus vaccines were not efficaciouis under field conditions. Unfortunately, Live Virulent Virus Inoculation (LVI) has been thought of as a last resort which leads to dramatic losses of animals and profits of an affected farm. As a result a number of requirements were presented in the white paper for the identification of an effective vaccine; 1 ? Rapid induction of immunity 2 ? Cross-protection against most currently prevalent strains 3 ? No adverse outcomes to swine health 4 ? DIVA (Differentiate Infected from Vaccinated Animals) 5 ? Simplicity of administration to ensure compliance. Based on these set criteria we believe that PRRS-RP technology not only has a potential significant advantage over traditional vaccines but also meets each of these requirements as a new effective PRRS vaccine. The objective of the proposal is to show the PRRS-RP vaccine candidate is not only able to significantly reduce viremia but is safe and efficacious. We aim to accomplish this by; determining if vaccinated pigs shed PRRS-RP and if so do non-vaccinated co-mingled pigs become infected. In response to this data we will determine if a non-target species is capable of shedding the PRRS-RP and if so can it infect other comingled animals. To aid in potency testing we aim to build on the current potency assay (IFA based) by developing a qPCR assay to quantify genome number (total particles / total genomes) giving a reproducible measure of complete PRRS-RP per dose hence aid in the determination of an effective dose. To determine the PRRS-RP product safety profile a study will be performed. These studies will position Harrisvaccines, Inc. to effectively pursue a USDA licensed product, to combat and alleviate the effects of PRRSV on the swine industry. In addition, this newly licensed product will not induce antibodies currently detected in the standard ELISA diagnostic test for PRRSV (DIVA) which will be essential in a national eradiction program, as endorsed by the AASV and producers.