NOTCH4 and infection: This level decreased to approximately 45 on day 1 p.i., then slightly increased to approximately 52 on day 4 p.i., before a sharp increase to approximately 90 on day 8 p.i. followed by another slight increase to approximately 95 on day 11 p.i. Vaccination-protected mice exhibited about the same constitutive level of Notch4 transcripts as unvaccinated mice, which decreased to approximately 35 upon infection on day 1 p.i., i.e., to a significantly (p-value < 0.05) lower level than in unvaccinated mice.