The University of Georgia College of Veterinary Medicine

Georgia Veterinary Scholars Program

GVSP Summer 2006 Scholars

Georgia Veterinary Scholar	Faculty Mentor

John Glidewell University of Georgia Class of 2009	Dr. Ralph Tripp

Silencing of Bovine Respiratory Syncytial Virus Replication by RNA Interference of Phosphoprotein mRNA

John T. Glidewell*, Deborah Haas, Nancy Pritchard, Amelia Woolums, and Ralph Tripp.

Department of Infectious Disease, Center for Disease Intervention, College of Veterinary Medicine, University of Georgia, Athens, GA.

Bovine respiratory syncytial virus (BRSV) is a member of the Paramyxoviridae family and is recognized as a major contributor to bovine respiratory disease. The agricultural and economic impact of BRSV is substantial, thus development of safe and effective vaccines and therapeutics remains a high priority. The recent development of RNA interference (RNAi) strategies to control virus replication has offered a new and novel approach for BRSV disease intervention. For human RSV (HRSV), small interfering RNA molecules (siRNAs) that mediate RNAi, when targeted to the phosphoprotein (P) gene of HRSV, have been shown to be a potent and specific antiviral strategy that prevents virus replication. In this study, we hypothesized that prophylactic intranasal delivery of siRNAs directed to the BRSV P gene (siRNA-P) would direct the degradation of BRSV P gene mRNA to inhibit virus replication, decrease the clinical signs of disease, and ameliorate lung pathology in BRSV-challenged calves. To test this, we screened several siRNA-P and missense control siRNAs in vitro using MDBK cells. The cells were transfected with siRNAs at a concentration of 100 nM six hours prior to infection with 100 pfu BRSV. The results show that we can effectively deliver the siRNAs to MDBK cells, and are currently in the process of determining the efficacy of siRNA-P by quantitating the reduction in the viral plaque number. Upon successful confirmation of in vitro activity, calves will be intranasally treated with the appropriate siRNA-P prior to virulent BRSV challenge. The results of this study should contribute to identifying a novel and virus specific therapy for the treatment and prevention of BRSV infection.