During the interaction of T cells with antigen presenting cells (APCs), receptors and intracellular proteins translocate into the contact region known as the Immunological Synapse (IS). In the first Aim we will examine whether CD8 behaves as a coreceptor within the immunological synapse, for the activation of peripheral T cells. In the other component of this proposal we shall follow up on our recent observation that cross-linking of CD8, but not CD4, with antibodies or MHC class I molecules, results in rapid apoptosis of CD4+CD8+ (DP) thymocytes. We have identified the thymocytes that are susceptible to this CD8 mediated apoptosis as an early DP population that expresses low levels of CD2 and CD5 and is CD69-. Treatment with the phorbol ester, PMA, or antibodies to CD3, prevents this induction of apoptosis. We hypothesize that ligation of CD8 by MHC class I molecules in the absence of TCR engagement leads to the death of a subpopulation of early DP thymocytes. Furthermore, our system may provide a model for thymocytes that fail positive selection and are said to undergo """"""""death by neglect"""""""". In this proposal we shall further characterize the induction of apoptosis in DP thymocytes by CD8 antibodies and MHC class I molecules according to 3 specific aims: (i) to determine the biochemical events leading to the CD8 mediated death of DP thymocytes; (ii) to determine the mechanism by which treatment with PMA, or engagement of the TCR, prevents CD8 mediated death in DP thymocytes; (iii) to determine whether CD8 mediated death functions under physiological conditions.

Agency
National Institute of Health (NIH)
Institute
National Institute of Allergy and Infectious Diseases (NIAID)
Type
Research Project (R01)
Project #
1R01AI055701-01A2
Application #
6869103
Study Section
Cellular and Molecular Immunology - B (CMI)
Program Officer
Macchiarini, Francesca
Project Start
2004-12-01
Project End
2009-11-30
Budget Start
2004-12-01
Budget End
2005-11-30
Support Year
1
Fiscal Year
2005
Total Cost
$198,975
Indirect Cost
Name
National Jewish Health
Department
Type
DUNS #
076443019
City
Denver
State
CO
Country
United States
Zip Code
80206
Kearney, Staci; Delgado, Christine; Lenz, Laurel L (2013) Differential effects of type I and II interferons on myeloid cells and resistance to intracellular bacterial infections. Immunol Res 55:187-200
Schmidt, Rebecca L; Lenz, Laurel L (2012) Distinct licensing of IL-18 and IL-1? secretion in response to NLRP3 inflammasome activation. PLoS One 7:e45186
Cole, Caroline; Thomas, Stacey; Filak, Holly et al. (2012) Nitric oxide increases susceptibility of Toll-like receptor-activated macrophages to spreading Listeria monocytogenes. Immunity 36:807-20
Jin, Lei; Hill, Krista K; Filak, Holly et al. (2011) MPYS is required for IFN response factor 3 activation and type I IFN production in the response of cultured phagocytes to bacterial second messengers cyclic-di-AMP and cyclic-di-GMP. J Immunol 187:2595-601
Schmidt, Rebecca L; Filak, Holly C; Lemon, Jack D et al. (2011) A LysM and SH3-domain containing region of the Listeria monocytogenes p60 protein stimulates accessory cells to promote activation of host NK cells. PLoS Pathog 7:e1002368
Knowles, Heather; Heizer, Justin W; Li, Yuan et al. (2011) Transient Receptor Potential Melastatin 2 (TRPM2) ion channel is required for innate immunity against Listeria monocytogenes. Proc Natl Acad Sci U S A 108:11578-83
Humann, Jessica; Lenz, Laurel L (2010) Activation of naive NK cells in response to Listeria monocytogenes requires IL-18 and contact with infected dendritic cells. J Immunol 184:5172-8
Rayamajhi, Manira; Humann, Jessica; Kearney, Staci et al. (2010) Antagonistic crosstalk between type I and II interferons and increased host susceptibility to bacterial infections. Virulence 1:418-22
Young, Ryan M; Hardy, Ian R; Clarke, Raedun L et al. (2009) Mouse models of non-Hodgkin lymphoma reveal Syk as an important therapeutic target. Blood 113:2508-16
Clarke, Raedun L; Thiemann, Sandra; Refaeli, Yosef et al. (2009) A new function for LAT and CD8 during CD8-mediated apoptosis that is independent of TCR signal transduction. Eur J Immunol 39:1619-31