EGF and infection: Moreover, in contrast to VGF’s capacity to restore EGFR phosphorylation levels upon vΔVGF infection, the observed decrease in EGFR phosphorylation in the presence of EGF peptide upon vΔVGF infection is indicative that VGF, despite its homology to cellular EGF, is markedly more efficacious in mediating EGFR activation upon VACV infection.