Detection of GP5 and M proteins in PRRSV VLPs. The protein components in the VLPs were determined by western blot. a The recombinant GP5 protein and the VLPs were reacted with rabbit anti-GP5 polyclonal antibody. A GP5-specific band was identified at 27.5 kDa. Lane 1, standard protein marker; lane 2, recombinant GP5 protein; lane 3, VLPs composed of the GP5 and M proteins. b VLPs were reacted with mouse anti-M monoclonal antibody. An M-protein-specific band was detected at 19 kDa. Lane 1, standard protein marker; lane 2, VLPs composed of the GP5 and M proteins