Fig. 1.

(a) Morphology of PRRSV Ags entrapped PLGA nanoparticles. Scanning electronic photomicrograph of PLGA nanoparticles prepared by a standard multiple emulsion method. The size of the nanoparticles appears to be variable ranging 200–600 nm. (b) Mucosal vaccination of pigs with PRRSV Ags entrapped in nanoparticles (Nano-KAg) cleared the viremia by PC 15. Pigs were unvaccinated (n = 3) or vaccinated with either killed PRRSV antigens (K-Ag) (n = 3) or Nano-KAg (n = 3) once, intranasally, and on DPI 21 challenged with PRRSV VR2332 strain. Serum samples collected on indicated post-challenge day (PC) were analyzed to measure PRRSV titers. Each bar represents the geometric mean of three pigs ± SEM.