Lnc641 overexpression enhances PRV replication. A 3D4/21 cells were transfected with 1 μg pcDNA3.1(+)-641 or pcDNA3.1(+). At 24 h post-transfection, the overexpression efficiency of lnc641 was determined by qRT-PCR. B–E 3D4/21 cells were transfected with the indicated doses of pcDNA3.1(+)-641 or pcDNA3.1(+) for 24 h, followed by infection with ZJ01 (0.01 MOI) for 24 h. The viral gB protein and mRNA levels were evaluated by qRT-PCR (B) and Western blot (C). The supernatant was used to measure viral titers by TCID50 analysis (D). The cells were treated as described previously, and IFA was performed with a primary anti-gB protein monoclonal antibody to analyze the antiviral effect of PRV. Viral gB-protein is green, and nuclei are blue (E). Results are presented as means ± SEM of from three independent experiments. *P value < 0.05, **P < 0.01, ***P < 0.0001.