Objectives To use microcarriers and a bioreactor to culture BHK cells and to inoculate those cells with the recombinant vaccinia virus rVTT-ORF2-EU-RF3O5 in order to establish a process for large-scale preparation of a recombinant vaccinia virus against Eu-PRRSV and PCV2. Methods Perfusion culture was performed using a working volume of 2Lto culture BHK cells.Culture parameters were a temperature of 37℃,a dissolved oxygen(DO)concentration of60%,a mixing speed of 80r/min,and a pH of 7.3.BHK cells were inocul...