Furthermore, compared to vvRB1B infection, the significant upregulation of interleukins and pro-inflammatory cytokines, including IL-1β and IL-6 under the influence of CVI988 (Figure 4) further postulated that the proliferation of Th1 cells under the influence of IL-6 and IL-1β might be a characteristic of the MDV vaccine in spleen. The gene discussed is IL1B; the disease is infection.