MCL1 and infection: Upon i.v. infection of mice with MVA for instance viral gene expression in spleen is primarily found in macrophages and dendritic cells.22 Similarly, MCMV has been found to infect monocytes and induce their differentiation to macrophages before spreading of the virus.28 In terms of anti-apoptotic proteins, macrophages are unique among the tested haematopoietic cells in that they do not depend on Mcl-1 for survival.12 This suggested that the viral strategy of replacing Mcl-1-function may not be able to protect macrophages during infection.