IL2 and infection: Cytokine withdrawal-induced cell death (CWID) is the critical apoptosis program responsible for culling the majority of effector T cells, triggered by waning interleukin-2 (IL-2) levels after an infection is cleared.8 CWID is primarily regulated by pro- and anti-apoptotic members of the B-cell lymphoma 2 (Bcl-2) protein family.9,10,11 Anti-apoptotic proteins such as Bcl-2 and Bcl-xL normally help to maintain mitochondrial outer membrane integrity.11,12 In the absence of IL-2 receptor (IL-2R) signaling, however, pro-apoptotic BH3-only proteins such as BIM are de-repressed.