The mechanism for generation of autoreactive alpha beta T cells in normal mice and their physiological significance in the immune system are not yet established. We have previously reported that generation of alpha beta T cells with reactivity to autologous cells occurs naturally and that such cells can be identified as a small alpha beta CD4+ T cell subset, termed """"""""Thy0"""""""" in the thymus. Thy0 cells promptly secrete a diverse array of cytokines upon incubation with autologous cells, particularly class II+ cells. Understanding the developmental mechanism and the fate of such autoreactive T cells is important since these cells have the potential to influence the immune response if appropriately activated. Our recent data suggest that NK1.1+ alpha beta cells, capable of TH2 cell induction and cytotoxicity, may represent the ultimate fate of Thy0. However, since there is an emerging consensus that the NK1.1+ alpha beta cell subset represents a third T cell """"""""lineage"""""""", recognizing the non-classical class I molecule CD1 as a ligand, our observation of class II dependent cell activation is difficult to reconcile. Therefore, we propose to investigate the mechanism of autoreactive alpha beta T cell generation and developmental relationship between Thy0 and NK1.1+ alpha beta T cell populations. Specifically, we will resolve whether the positive selection of autoreactive cells is accounted for simply because the cell possesses an intermediate TCR affinity/avidity or instead results from a unique selection mechanism operating during early ontogeny (Aim 1 and 20. Furthermore, we will determine whether the NK alpha beta cell phenotype results from preferential survival of autoreactive T cells influenced by a balance of receptor-ligand mediated signals (Aim 3 and 4). These investigations encompass our long-term goal to understand the developmental mechanism and functional significance of natural autoreactive lymphocytes in the immune system.

Agency
National Institute of Health (NIH)
Institute
National Institute of Allergy and Infectious Diseases (NIAID)
Type
Research Project (R01)
Project #
5R01AI041726-05
Application #
6373688
Study Section
Special Emphasis Panel (ZRG2-ALY (02))
Program Officer
Nabavi, Nasrin N
Project Start
1997-07-01
Project End
2003-06-30
Budget Start
2001-07-01
Budget End
2003-06-30
Support Year
5
Fiscal Year
2001
Total Cost
$239,541
Indirect Cost
Name
Institute for Cancer Research
Department
Type
DUNS #
872612445
City
Philadelphia
State
PA
Country
United States
Zip Code
19111
Roberts, Tonya J; Sriram, Venkataraman; Spence, Philip M et al. (2002) Recycling CD1d1 molecules present endogenous antigens processed in an endocytic compartment to NKT cells. J Immunol 168:5409-14
Gui, M; Li, J; Wen, L J et al. (2001) TCR beta chain influences but does not solely control autoreactivity of V alpha 14J281T cells. J Immunol 167:6239-46