The most differently expressed proteins (p < 0.001) in PEV were pregnancy zone protein (PZP) (α2-macroglobulin protease inhibiter associated with pregnancy (47)], cytochrome b5 reductase 1 (CBR1) [a NADPH-dependent oxidoreductase important in ATP production found to decrease oxidative stress and inflammation (48, 49)], endophilin-β2 (SH3GLB2) [elevated after viral infection, associated with autophagy (50, 51)], and immunoglobulins (Ig) V2-14 and V3-9 (Figure 4C). Here, CYB5R1 is linked to viral infectious disease.