Figure 2. PRRSV nonstructural proteins nsp2 and nsp4 induced apoptosis.

Marc-145 cells were transfected with each of the PRRSV structural protein expression vectors (A), nonstructural protein expression vectors (B), or pcDNA 3.1 (+) vector as control. At 48 hours post transfection, cells were fixed for TUNEL analysis. Results represent means ± SD of three independent experiments. P<0.01 (**) as determined by student’s t test.