CREB1 and infection: However, when normalized to account for the intrinsic differences observed at baseline between uninfected P2X7R-/- and wild-type C57BL/6J mice, infection did not differentially induce the phosphorylation of NFκB (Fig 4F) or CREB (Fig 4H), but elevated levels of phosphorylated IκB (Fig 4E) and p38 MAPK (Fig 4G) were identified in P2X7R-/- mice, although this did not reach statistical significance using a two-way ANOVA test.