Molecular Characterization of Epitopes for Porcine Respiratory and Reproductive Virus

Porcine reproductive and respiratory syndrome was recognized in the U.S. in 1987 as a new infectious disease of swine causing late-term reproductive failure and severe pneumonia in neonatal pigs. The etiological agent is PRRS virus (PRRSV). Current attenuated vaccines against PRRSV are not totally effective in prevention of the infection and disease. In addition, there is emerging evidence that the current attenuated vaccines are not 100% safe due to reversion to virulence. A new generation of safe vaccines with a better performance will help in prevention of this disease. Most, if not all, viral vaccines protect via preexistent specific neutralizing antibodies. There is also strong evidence for a protective role of neutralizing antibodies in protection to PRRSV infection. We propose here to characterize neutralizing epitopes (mimotopes) for PRRSV using phage display libraries of peptides. To select the mimotopes we will take advantage of the characteristic features of porcine antibodies and the humoral response of swine to PRRSV infection. The capacity of these mimotopes to compete to neutralizing anti- PRRSV antibodies will be tested in vitro and selected ones will be used to induce a neutralizing antibody response as a proof of principle.