The differential genes among the immunization-challenged group, the challenged group and the mock group were mainly enriched in complement and coagulation cascades, TNF signaling pathway, osteoclast differentiation, MAPK signaling pathway, Toll-like receptor signaling pathway, NOD-like receptor signaling pathway, influenza A, human cytomegalovirus infection, cytokine-cytokine receptor interaction, herpes simplex virus 1 infection, cholesterol metabolism, and IL-17 signaling pathway (Figure 3D). Here, TNF is linked to cytomegalovirus infection.