title: Bim/Bcl-2 balance is critical for maintaining naive and memory T cell homeostasis.
abstract: We examined the role of the antiapoptotic molecule Bcl-2 in combating the proapoptotic molecule Bim in control of naive and memory T cell homeostasis using Bcl-2(-/-) mice that were additionally deficient in one or both alleles of Bim. Naive T cells were significantly decreased in Bim(+/-)Bcl-2(-/-) mice, but were largely restored in Bim(-/-)Bcl-2(-/-) mice. Similarly, a synthetic Bcl-2 inhibitor killed wild-type, but not Bim(-/-), T cells. Further, T cells from Bim(+/-)Bcl-2(-/-) mice died rapidly ex vivo and were refractory to cytokine-driven survival in vitro. In vivo, naive CD8(+) T cells required Bcl-2 to combat Bim to maintain peripheral survival, whereas naive CD4(+) T cells did not. In contrast, Bim(+/-)Bcl-2(-/-) mice generated relatively normal numbers of memory T cells after lymphocytic choriomeningitis virus infection. Accumulation of memory T cells in Bim(+/-)Bcl-2(-/-) mice was likely caused by their increased proliferative renewal because of the lymphopenic environment of the mice. Collectively, these data demonstrate a critical role for a balance between Bim and Bcl-2 in controlling homeostasis of naive and memory T cells.
authors.affiliation: Division of Immunobiology, Cincinnati Children's Hospital, Cincinnati, OH 45229, USA.
authors.forename: Sara
authors.initials: S
authors.lastname: Wojciechowski
authors.forename: Pulak
authors.initials: P
authors.lastname: Tripathi
authors.forename: Tristan
authors.initials: T
authors.lastname: Bourdeau
authors.forename: Luis
authors.initials: L
authors.lastname: Acero
authors.forename: H Leighton
authors.initials: HL
authors.lastname: Grimes
authors.forename: Jonathan D
authors.initials: JD
authors.lastname: Katz
authors.forename: Fred D
authors.initials: FD
authors.lastname: Finkelman
authors.forename: David A
authors.initials: DA
authors.lastname: Hildeman
mesh_terms: D000818:Animals; D051017:Apoptosis Regulatory Proteins / Q000172:deficiency / Q000235:genetics / Q000502:physiology*; D000072224:Bcl-2-Like Protein 11; D001853:Bone Marrow / Q000276:immunology / Q000502:physiology; D006706:Homeostasis; D007156:Immunologic Memory / Q000502:physiology*; D015851:Interleukin-7 / Q000172:deficiency; D008213:Lymphocyte Activation; D008216:Lymphocytic Choriomeningitis / Q000276:immunology; D008565:Membrane Proteins / Q000172:deficiency / Q000235:genetics / Q000502:physiology*; D051379:Mice; D018345:Mice, Knockout; D011518:Proto-Oncogene Proteins / Q000172:deficiency / Q000235:genetics / Q000502:physiology*; D019253:Proto-Oncogene Proteins c-bcl-2 / Q000172:deficiency / Q000235:genetics / Q000502:physiology*; D013601:T-Lymphocytes / Q000276:immunology* / Q000502:physiology; D013934:Thymectomy
chemical_list: D051017:Apoptosis Regulatory Proteins; D000072224:Bcl-2-Like Protein 11; C000606776:Bcl2l11 protein, mouse; D015851:Interleukin-7; D008565:Membrane Proteins; D011518:Proto-Oncogene Proteins; D019253:Proto-Oncogene Proteins c-bcl-2