CD4 and infection: Looking at the composition of the infiltrate at later time points (from day 12), as well as the chemokine and cytokine levels, it is striking that infection with PrV‐∆UL21/US3∆kin led to a polarization of the brain infiltrate from mainly CD4+ T cell response toward a Th1 chemokine profile (CXCL10) and a subsequent CD8+ T cell infiltration.