Fig. 3

Expression (a), purification (b), and western blotting analysis (c) of rLip40 protein. Protein samples were separated with 12 % SDS-PAGE and blotted onto nitrocellulose membrane. The membrane was sequentially incubated with porcine convalescent serum directed against A. pleuropneumoniae and HRP-labeled goat anti-porcine IgG secondary antibody, and the color was developed with a 3,3′-diaminobenzidine (DAB) peroxidase substrate (Tiangen, Beijing, China). M, prestained protein ladder (Fermentas, Vilnius, Lithuania); lane 1, GST; lane 2, rLip40