CTLA4 and infection: In this model however, the presence of apoptotic cells including apoptotic neurons, and a pattern of gene expression that suggest the presence of activated microglia/macrophage (C3, Tnf, Ccl5, Cxcl10), ongoing antigen presentation (β2m, H2-Eb1, Cd86), and activated T cells (Cd3ε, Cd8, Cd4, Ifnγ, GrzmB, Prf1, but not Ctla4 or Pd1) as late as a year post infection suggests that the cells infiltrating these foci are not quiescent, but actively responding and possibly controlling the infection.