CD40 and infection: Of interest, 11 genes were not found to be significantly influenced by RSV infection over days 1, 3, or 5, including CD40, CD80, IFIH1, IL-18, JUN, MAPK3, MyD88, NFKB1, PYCARD, TBKBP1, and TRAF3. For the remainder of the study we focused on cytokines, OPN and IL-1β (upregulated >3-fold after infection in young mice) because of their associated roles in leukocyte migration and inflammasome activation, respectively.