Porcine Kidney Cell Culture and PCV2 Infection

Porcine kidney 15 (PK15) cells purchased from ATCC (CCL-33) were cultured in Dulbecco’s Modified Eagle’s Medium (Gibco BRL, Gaithersburg, MD, USA) supplemented with 10% heat-inactivated fetal bovine serum (Thermo Scientific HyClone, Beijing, China), and incubated at 37 °C in a 5% CO₂ atmosphere incubator. The PCV2 strains (GenBank No. EU366323) used in this study were isolated and purified previously by our team and stocked in our laboratory, the UV-inactivation was performed by UV radiation of the virus for 45 min in the hood. The anti-PCV2 Cap primary antibodies were produced by our team [12 (link), 13 (link)]. The primary monoclonal rabbit antibodies of p53, p21 and anti-BrdU were purchased from Cell Signaling (Cell Signaling Technology, Danvers, MA, USA). CDK2, Cyclin A and Cyclin E antibodies were purchased from Santa Cruz Biotechnology (Santa Cruz, California, CA, USA). The monoclonal antibody of β-actin was purchased from sigma (Sigma-Aldrich, St. Louis, MO, USA). The FITC goat anti-mouse IgG was purchased from BD Biosciences (BD, San Jose, CA, USA).