CASP3 and infection: By in situ detection of effector caspase-3 (recall Fig 2A) previous work by Cicin-Sain and colleagues [76] has unequivocally shown that infection with mCMV-ΔM36 leads to apoptosis of infected cells in vivo, including liver macrophages, and that this phenotype of effector caspase-3 expression is reversed after infection with mCMV-ΔM36-Rev blocking apoptosis.