Following the infection of lymphocytes with PCV2, this study showed an increase in the expression of p-IκB (from 24 h after inoculation), the expression of p65 in the nucleus (from 6 h), and NF-κB DNA-binding activity (from 12 h) compared to controls, demonstrating that NF-κB signaling was activated in lymphocytes by PCV2 infection, a result consistent with previous reports [16], [20]–[21]. The gene discussed is NFKB1; the disease is infection.