To further confirm that FcRn is important for multiple PRRSV strains infection, three single-gene KO and WT cells were inoculated with PRRSV-2 strain XJ (sublineage 8.7), JXA1-R (attenuated vaccine strain from HP-RRSV strain JXA1), and R98 (sublineage 5.1). The gene discussed is FCGRT; the disease is infection.