Apoptosis regulators Fas and Bim cooperate in shutdown of chronic immune responses and prevention of autoimmunity - PubMed (original) (raw)

Apoptosis regulators Fas and Bim cooperate in shutdown of chronic immune responses and prevention of autoimmunity

Peter D Hughes et al. Immunity. 2008 Feb.

Abstract

Apoptotic death of T lymphocytes is critical for shutdown of immune responses and hemopoietic cell homeostasis. Both death receptor (Fas) activation and mitochondrial apoptosis triggered by the BH3-only protein Bim have been implicated in the killing of antigen-stimulated T cells. We examined mice lacking the gene encoding Bim (Bcl2l11) and with the inactivating lpr mutation in the gene encoding Fas (Fas), designated Bcl2l11(-/-)Fas(lpr/lpr) mice. Shutdown of an acute T cell response to herpes simplex virus involved only Bim with no contribution by Fas, whereas both pathways synergized in killing antigen-stimulated T cells in chronic infection with murine gamma-herpesvirus. Bcl2l11(-/-)Fas(lpr/lpr) mice developed remarkably enhanced and accelerated fatal lymphadenopathy and autoimmunity compared to mice lacking only one of these apoptosis inducers. These results identify critical overlapping roles for Fas and Bim in T cell death in immune response shutdown and prevention of immunopathology and thereby resolve a long-standing controversy.

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Figures

Figure 1

Figure 1

Leukocytes from Bcl2l11−/−Faslpr/lpr Mice Are Resistant to Both FasL as well as to Bim-Dependent Apoptotic Stimuli (A) CD4+8+ thymocytes from mice of the genotypes indicated were purified by FACS after staining with antibodies to CD4 and CD8. Cells were challenged in culture with the apoptotic stimuli indicated and survival assessed daily by propidium iodide staining and FACS analysis. (B and C) Similar experiments were performed with CD4+CD8− and CD4−CD8+ T cells (B) and αβTCR+CD4−CD8−B220+ T cells (C) purified from lymph nodes of mice of the genotypes indicated. Data represent the mean ± SEM of 3–7 mice for each genotype.

Figure 2

Figure 2

Accumulation of Leukocytes, Total CD8+ T Cells, and HSV-1-Specific CD8+ T Cells in Bcl2l11−/−Faslpr/lpr, Bcl2l11−/−, Faslpr/lpr, or WT Mice after HSV-1 Infection (A–D) Total numbers of leukocytes (A, C) and total numbers of CD8+ T cells (B, D) from spleen and popliteal lymph nodes of HSV-1-infected mice were quantified by cell counting and staining with CD8 mAbs followed by FACS analysis. Data from spleens represent the mean ± SEM from 3–4 mice of each genotype (2 for Bcl2l11+/−Faslpr/lpr). Lymph node samples from mice of the same genotype (3–4 mice of each genotype except 2 for Bcl2l11+/−Faslpr/lpr) were pooled and analyzed together 17 and 35 days after infection. (E and F) Mice of the indicated genotypes were injected subcutaneously with HSV-1 in each hindfoot, and HSV-specific CD8+ T cells in spleen (E) and popliteal lymph nodes (F) were enumerated after 17 and 35 days by immunofluorescent staining with antibodies to CD8 plus PE-streptavidin-conjugated Kb tetramers loaded with the immunodominant HSV-1 epitope followed by FACS analysis. Lymph node samples from mice of the same genotype were pooled. Data points represent the mean ± SEM of 3–4 mice (2 for Bcl2l11+/−Faslpr/lpr).

Figure 3

Figure 3

After Intranasal MHV-OVA Infection, Bcl2l11−/−Faslpr/lpr Mice Accumulate More Viral Antigen-Specific CD8+ T Cells than Bcl2l11−/−, Faslpr/lpr, or WT Mice Mice were infected intranasally with MHV-OVA and sacrificed after 14, 40, or 60 days, and mediastinal lymph nodes and spleen were analyzed. (A–D) Total leukocytes (A, B) and total numbers of CD8+ T cells (C, D) from spleen and mediastinal lymph nodes were quantified by cell counting and staining with CD8 mAbs followed by FACS analysis. Data represent the mean ± SEM from 3–4 mice of each genotype. Lack of data at day 14 for the Bcl2l11+/−Faslpr/lpr genotype is indicated with an asterisk. (E–H) MHV-OVA-specific CD8+ T cells were measured by immunofluorescent staining with PE-streptavidin-conjugated Kb/SIINFEKL tetramers plus antibodies to CD8 (E, F), or, after brief antigenic stimulation in vitro, by intracellular staining for IFN-γ (G, H), both followed by FACS analysis. Lymph node samples from mice of the same genotype were pooled. Data points represent the mean ± SEM of 3–4 mice (2 mice at some time points for Bcl2l11+/−Faslpr/lpr and Faslpr/lpr mice).

Figure 4

Figure 4

Loss of Bim and Fas Synergize in the Development of Lymphadenopathy and Splenomegaly Mice (WT, Bcl2l11−/−, Faslpr/lpr, Bcl2l11+/−Faslpr/lpr, and Bcl2l11−/−Faslpr/lpr) were analyzed between the ages of 6 and 10 weeks. Spleen and lymph node cells were counted and analyzed by immunofluorescent staining with surface marker-specific antibodies and FACS analysis. Data represent mean ± SEM from 3–6 mice of each genotype.

Figure 5

Figure 5

Bcl2l11−/−Faslpr/lpr Mice Have a Normal Polyclonal Usage of TCR-Vβ Chains in Lymph Node T Cells TCR-Vβ chain expression on lymph node T cells from Bcl2l11−/−Faslpr/lpr and WT mice was analyzed by FACS after staining with mAbs to Thy-1 plus mAbs to Vβ3, Vβ4, Vβ5, Vβ6, Vβ7, Vβ8, or Vβ10. The percentages of T cells expressing each TCR-Vβ chain and the mean are represented.

Figure 6

Figure 6

Accelerated Immunopathology and Premature Death in Bcl2l11−/−Faslpr/lpr and Bcl2l11+/−Faslpr/lpr Mice (A) Lungs (i, iv), kidney (ii, v), and liver (iii, vi) of a 260-day-old Bcl2l11+/+Faslpr/lpr mouse (i, ii, iii) and a 114-day-old Bcl2l11−/−Faslpr/lpr mouse (iv, v, vi) showing large lymphocyte infiltrates in Bcl2l11−/−Faslpr/lpr tissues. Scale bars represent 1 mm. (B) Bcl2l11−/−Faslpr/lpr (n = 8) and Bcl2l11+/−Faslpr/lpr (n = 10) mice were found dead in their cages at the indicated times. No Bcl2l11+/+Faslpr/lpr, Bcl2l11−/− or WT mice (n = 10) were found dead by 250 days. p < 0.001 for both Bcl2l11+/−Faslpr/lpr and Bcl2l11−/−Faslpr/lpr mice. (C) Model for induction of apoptosis in T lymphocytes during shutdown of an acute or chronic immune response. Single stimulation of the TCR in an acute response triggers activated T cell death via Bim, whereas repeated stimulation in a chronic infection recruits Fas to contract the activated T cell population.

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References

    1. Ashkenazi A., Dixit V.M. Death receptors: signaling and modulation. Science. 1998;281:1305–1308. - PubMed
    1. Bouillet P., Metcalf D., Huang D.C.S., Tarlinton D.M., Kay T.W.H., Köntgen F., Adams J.M., Strasser A. Proapoptotic Bcl-2 relative Bim required for certain apoptotic responses, leukocyte homeostasis, and to preclude autoimmunity. Science. 1999;286:1735–1738. - PubMed
    1. Bouillet P., Purton J.F., Godfrey D.I., Zhang L.-C., Coultas L., Puthalakath H., Pellegrini M., Cory S., Adams J.M., Strasser A. BH3-only Bcl-2 family member Bim is required for apoptosis of autoreactive thymocytes. Nature. 2002;415:922–926. - PubMed
    1. Brunner T., Mogil R.J., LaFace D., Yoo N.J., Mahboubi A., Echeverri F., Martin S.J., Force W.R., Lynch D.H., Ware C.F. Cell-autonomous Fas (CD95)/Fas-ligand interaction mediates activation-induced apoptosis in T-cell hybridomas. Nature. 1995;373:441–444. - PubMed
    1. Davey G.M., Kurts C., Miller J.F., Bouillet P., Strasser A., Brooks A.G., Carbone F.R., Heath W.R. Peripheral deletion of autoreactive CD8 T cells by cross presentation of self-antigen occurs by a Bcl-2-inhibitable pathway mediated by Bim. J. Exp. Med. 2002;196:947–955. - PMC - PubMed

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