Naive antigen-specific T lymphocytes require stimulation via their T cell receptor (TCR) and costimulatory molecules in order to become activated, secrete cytokines, clonally expand, and mount an immune response. When TCR is ligated by antigen alone without costimulation or IL-2, T cells become anergic and are incapable of clonally expanding and transcribing the IL-2 gene. In anergic cells many of the critical signals initiated by T cell activation do not occur, whereas other signals predominate. Anergic cells have defective activation of lck, ZAP 70, Ras, ERK, JKN and Trans activation of AP-1 and NF-AT. In contrast, these cells activate fyn, increase calcium levels, and activate Rap1, indicating that induction of anergy requires active signaling events. We have recently determined that anergizing signals result in increased intracellular cAMP that upregulates the cyclin dependent kinase (cdk) inhibitor p27kipl, rendering cyclin D2 cdk4 defective and preventing progression of T cells through the Gl restriction point of the cell cycle. In contrast, CD28 costimulation prevents p27kipl accumulation by decreasing the levels of intracellular cAMP and promoting ubiquitin-dependent degradation of p27kipl. p27kipl associates with JABi, a coactivator of cJun transcription factor, resulting in its cytoplasmic translocation and defective AP-1 transactivation. Better understanding of the biochemical and molecular basis of T cell anergy will facilitate the reversal of the anergic state of tumor-specific T cells isolated from cancer patients in order to make them capable of clonal expansion prior to the administration of tumor vaccines or immunotherapy. Understanding the molecular basis of T cell anergy will also provide targets to fashion more specific treatment approaches instead of global immunosuppression to prevent graft rejection and GVHD in patients undergoing allogeneic bone marrow and organ transplantation. Although our findings strongly suggest that p27kipl functions as an anergy factor, the regulation of p27kipl expression during T cell activation and the precise mechanism by which it mediates induction and maintenance of the anergic state remain unclear. To achieve these goals I propose three specific aims: 1) to identify the biochemical modification of p27kipl in T cell immunity and anergy 2) to identify molecules that associate with p27kipl and study their role in T cell immunity and anergy, and 3) to determine the role of p27kipl in the stimulation of naive and activated antigen-specific T cells in vitro and in vivo.

Agency
National Institute of Health (NIH)
Institute
National Institute of Allergy and Infectious Diseases (NIAID)
Type
Research Project (R01)
Project #
5R01AI046548-02
Application #
6534219
Study Section
Experimental Immunology Study Section (EI)
Program Officer
Nabavi, Nasrin N
Project Start
2001-09-15
Project End
2004-06-30
Budget Start
2002-09-01
Budget End
2003-06-30
Support Year
2
Fiscal Year
2002
Total Cost
$267,091
Indirect Cost
Name
Dana-Farber Cancer Institute
Department
Type
DUNS #
149617367
City
Boston
State
MA
Country
United States
Zip Code
02215
Li, Lequn; Iwamoto, Yoshiko; Berezovskaya, Alla et al. (2006) A pathway regulated by cell cycle inhibitor p27Kip1 and checkpoint inhibitor Smad3 is involved in the induction of T cell tolerance. Nat Immunol 7:1157-65
Appleman, Leonard J; Chernova, Irina; Li, Lequn et al. (2006) CD28 costimulation mediates transcription of SKP2 and CKS1, the substrate recognition components of SCFSkp2 ubiquitin ligase that leads p27kip1 to degradation. Cell Cycle 5:2123-9
Li, Lequn; Greenwald, Rebecca J; Lafuente, Esther M et al. (2005) Rap1-GTP is a negative regulator of Th cell function and promotes the generation of CD4+CD103+ regulatory T cells in vivo. J Immunol 175:3133-9
Li, Lequn; Godfrey, Wayne R; Porter, Stephen B et al. (2005) CD4+CD25+ regulatory T-cell lines from human cord blood have functional and molecular properties of T-cell anergy. Blood 106:3068-73
Barata, Joao T; Cardoso, Angelo A; Boussiotis, Vassiliki A (2005) Interleukin-7 in T-cell acute lymphoblastic leukemia: an extrinsic factor supporting leukemogenesis? Leuk Lymphoma 46:483-95
Barata, Joao T; Silva, Ana; Brandao, Joana G et al. (2004) Activation of PI3K is indispensable for interleukin 7-mediated viability, proliferation, glucose use, and growth of T cell acute lymphoblastic leukemia cells. J Exp Med 200:659-69
Tzachanis, Dimitrios; Lafuente, Esther M; Li, Lequn et al. (2004) Intrinsic and extrinsic regulation of T lymphocyte quiescence. Leuk Lymphoma 45:1959-67
Grader-Beck, Thomas; van Puijenbroek, Andre A F L; Nadler, Lee M et al. (2003) cAMP inhibits both Ras and Rap1 activation in primary human T lymphocytes, but only Ras inhibition correlates with blockade of cell cycle progression. Blood 101:998-1006
Appleman, Leonard J; Boussiotis, Vassiliki A (2003) T cell anergy and costimulation. Immunol Rev 192:161-80
Appleman, Leonard J; Tzachanis, Dimitrios; Grader-Beck, Thomas et al. (2002) Induction of immunologic tolerance for allogeneic hematopoietic cell transplantation. Leuk Lymphoma 43:1159-67

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