Maintenance of T cell homeostasis is critical for normal functioning of the adaptive immune system. Although T cell homeostasis is ultimately achieved through maintenance of distinct T cell populations (naive, effector, memory), the mechanisms by which homeostasis is maintained in each population is unclear. Although IL-7 is critical for survival of T cells in vivo at each of these stages, little is known about the downstream survival mechanisms by which homeostasis of distinct T cell populations are controlled. Our preliminary data indicate that the anti-apoptotic molecule, Bim and its anti-apoptotic antagonist, Bcl-2, regulate T cell homeostasis, at least in part by altering T cell survival in distinct populations. Bcl-2 is critical for naive T cell survival, at least in part, to counteract the pro-apoptotic effects of Bim. In viral-specific effector T cells, levels of IL-7Ralpha and Bcl-2 are decreased on most viral-specific T cells, leaving them susceptible to the pro-apoptotic effects of Bim. In the absence of Bim the numbers of a particular type of viral-specific memory T cell are increased, both functionally and phenotypically. These data suggest that the role of Bim is to limit the numbers of effector T cells that can enter the memory compartment. However, not all memory T cells are affected and the long-term survival of memory T cells may not require Bim or Bcl-2. Taken together, these data suggest that the maintenance of independent populations of T cells within the host is controlled by their different dependence on apoptosis/survival molecules. The central hypothesis of this proposal is that progression from naive to memory T compartments Involves stage-specific dependence on a dynamic balance between Bim and Bcl-2, a balance that affects IL-7-dependent survival of naive, effector, and effector memory but not central memory T cells.
The aims of the project are to determine the roles of Bim and Bcl-2 in : 1. naive T cell homeostasis; 2. effector T cell apoptosis; 3. memory T cell survival and phenotype. The long-term goal of this research is to identify molecular targets that could be exploited therapeutically to enhance T cell survival (i.e. to improve vaccination) or to decrease T cell survival (i.e. suppress autoimmune disease or transplant rejection).
|McNally, Jonathan P; Millen, Scott H; Chaturvedi, Vandana et al. (2017) Manipulating DNA damage-response signaling for the treatment of immune-mediated diseases. Proc Natl Acad Sci U S A 114:E4782-E4791|
|Li, Kun-Po; Fähnrich, Anke; Roy, Eron et al. (2017) Temporal Expression of Bim Limits the Development of Agonist-Selected Thymocytes and Skews Their TCR? Repertoire. J Immunol 198:257-269|
|Tripathi, Pulak; Morris, Suzanne C; Perkins, Charles et al. (2016) IL-4 and IL-15 promotion of virtual memory CD8+ T cells is determined by genetic background. Eur J Immunol 46:2333-2339|
|Ladle, Brian H; Li, Kun-Po; Phillips, Maggie J et al. (2016) De novo DNA methylation by DNA methyltransferase 3a controls early effector CD8+ T-cell fate decisions following activation. Proc Natl Acad Sci U S A 113:10631-6|
|Kurtulus, S; Sholl, A; Toe, J et al. (2015) Bim controls IL-15 availability and limits engagement of multiple BH3-only proteins. Cell Death Differ 22:174-84|
|Niss, Omar; Sholl, Allyson; Bleesing, Jack J et al. (2015) IL-10/Janus kinase/signal transducer and activator of transcription 3 signaling dysregulates Bim expression in autoimmune lymphoproliferative syndrome. J Allergy Clin Immunol 135:762-70|
|Tripathi, P; Koss, B; Opferman, J T et al. (2013) Mcl-1 antagonizes Bax/Bak to promote effector CD4(+) and CD8(+) T-cell responses. Cell Death Differ 20:998-1007|
|Kurtulus, Sema; Hildeman, David (2013) Assessment of CD4(+) and CD8 (+) T cell responses using MHC class I and II tetramers. Methods Mol Biol 979:71-9|
|Sena, Laura A; Li, Sha; Jairaman, Amit et al. (2013) Mitochondria are required for antigen-specific T cell activation through reactive oxygen species signaling. Immunity 38:225-36|
|Raynor, Jana; Lages, Celine S; Shehata, Hesham et al. (2012) Homeostasis and function of regulatory T cells in aging. Curr Opin Immunol 24:482-7|
Showing the most recent 10 out of 28 publications