T cell homeostasis is the maintenance of peripheral T cells at a relatively constant level. When total T cell numbers are reduced, the remaining T cells proliferate to restore the normal T cell number. Similarly, naive T cells proliferate when a small number is transferred into lymphopenic hosts such as mice deficient in recombination activating gene-1 (RAG1-/-). The homeostatic T cell proliferation requires the recognition of cognate self-peptide/MHC (pepMHC) complexes by T cell receptor (TCR) and a lymphopenic condition, or """"""""space."""""""" Recent studies have further shown that as naive CD8 T cells proliferate in lymphopenic hosts, they progressively acquire cell surface markers and functional properties of antigen-induced memory CD8 T cells. The long-term goal of the proposed studies is to understand molecular mechanisms that promote T cell proliferation and differentiation in lymphopenic hosts. Findings from the proposed studies may help to better understand T cell homeostasis and mechanisms underlying the increased incidence of autoimmune diseases in lymphopenic individuals, as in those with AIDS and in patients given radiation, or chemotherapy and bone marrow transplants.
Specific aim #1 will identify the molecular basis of """"""""space"""""""" for homeostatic T cell proliferation. Using a novel T cell-dendritic cell (T-DC) cocuture system in which T cell proliferation mimics homeostatic proliferation in mice, dendritic cells were found to produce soluble factors that stimulate T cell proliferation. The stimulatory factors secreted by dendritic cells will be identified by screening candidate factors and by biochemical purification. Once they are identified, their role in homeostatic T cell proliferation in mice will be evaluated. In addition, whether """"""""space"""""""" involves relief of inhibitory signals among T cells or stimulatory cell-cell contacts mediated by receptors other than TCR will be investigated m the T-DC coculture system.
Specific aim #2 will characterize a fraction of polyclonal CD4 and CD8 T cells that undergo exceptionally rapid proliferation in syngeneic lymphopenic hosts. The activation status, repertoire diversity and the ability to respond to environmental antigens by the rapidly proliferating T cells will be analyzed.
Specific aim #3 will investigate the role of cell proliferation in homeostasis-driven differentiation and maintenance of memory-like T cells. Naive TCR transgenic T cells expressing the Coxsackie and adenovirus receptor (CAR) will be infected with adenovirus expressing a cyclin dependent kinase inhibitor gene to evaluate the effects of inhibiting cell division on homeostasis-driven differentiation of memory-like cells. Proliferation of homeostatic memory CD8 T cells will be similarly inhibited to evaluate the effects on the maintenance of their surface phenotype and functional characteristics. In addition, the role of cell division in facilitating changes in chromatin structure at the IFN-g locus will be investigated by measuring the extent of DNA methylation, histone acetylation and factor binding.

Agency
National Institute of Health (NIH)
Institute
National Institute of Allergy and Infectious Diseases (NIAID)
Type
Research Project (R01)
Project #
5R01AI050631-04
Application #
6886098
Study Section
Special Emphasis Panel (ZRG1-SSS-F (01))
Program Officer
Nabavi, Nasrin N
Project Start
2002-05-05
Project End
2007-04-30
Budget Start
2005-05-01
Budget End
2006-04-30
Support Year
4
Fiscal Year
2005
Total Cost
$322,670
Indirect Cost
Name
Massachusetts Institute of Technology
Department
Internal Medicine/Medicine
Type
Schools of Arts and Sciences
DUNS #
001425594
City
Cambridge
State
MA
Country
United States
Zip Code
02139
Roper, Jatin; Tammela, Tuomas; Cetinbas, Naniye Malli et al. (2017) In vivo genome editing and organoid transplantation models of colorectal cancer and metastasis. Nat Biotechnol 35:569-576
Chervin, Adam S; Stone, Jennifer D; Holler, Phillip D et al. (2009) The impact of TCR-binding properties and antigen presentation format on T cell responsiveness. J Immunol 183:1166-78
Leng, Qibin; Nie, Yuchun; Zou, Yongrui et al. (2008) Elevated CXCL12 expression in the bone marrow of NOD mice is associated with altered T cell and stem cell trafficking and diabetes development. BMC Immunol 9:51
Bai, Ailin; Higham, Eileen; Eisen, Herman N et al. (2008) Rapid tolerization of virus-activated tumor-specific CD8+ T cells in prostate tumors of TRAMP mice. Proc Natl Acad Sci U S A 105:13003-8
Kocher, Olivier; Yesilaltay, Ayce; Shen, Ching-Hung et al. (2008) Influence of PDZK1 on lipoprotein metabolism and atherosclerosis. Biochim Biophys Acta 1782:310-6
Bai, Ailin; Hu, Hui; Yeung, Mandy et al. (2007) Kruppel-like factor 2 controls T cell trafficking by activating L-selectin (CD62L) and sphingosine-1-phosphate receptor 1 transcription. J Immunol 178:7632-9
Leng, Qibin; Ge, Qing; Nguyen, Tam et al. (2007) Stage-dependent reactivity of thymocytes to self-peptide--MHC complexes. Proc Natl Acad Sci U S A 104:5038-43
Ge, Qing; Holler, Phillip D; Mahajan, Vinay S et al. (2006) Development of CD4+ T cells expressing a nominally MHC class I-restricted T cell receptor by two different mechanisms. Proc Natl Acad Sci U S A 103:1822-7
Jones, Brendan; Chen, Jianzhu (2006) Inhibition of IFN-gamma transcription by site-specific methylation during T helper cell development. EMBO J 25:2443-52
Mahajan, Vinay S; Leskov, Ilya B; Chen, Jian Zhu (2005) Homeostasis of T cell diversity. Cell Mol Immunol 2:1-10

Showing the most recent 10 out of 19 publications