PCV2 replication is required for JNK1/2 and p38 MAPK phosphorylation. Monolayer PK15 cells were infected with PCV2 strain BJW at an MOI of 1 TCID50. PCV2-infected cells at 0.25, 1, 3, 5, and 24 h as well as UV-irradiated PCV2-infected cells at 72 h were fixed with 4% formaldehyde. A FACE assay was used for determination of JNK1/2 (A) or p38 (B) activation. JNK1/2 and p38 and their phosphorylated forms were each assayed in triplicate. Cell numbers were normalized by using crystal violet. These results are representative of three independent experiments. Values are means ± the SD from triplicate wells. p-, Phosphorylated.