CD4+ T cells recognize exogenously derived peptide antigens. The antigens are taken up by APCs and loaded onto newly synthesized MHC class II molecules that intersect with an endosomal-lysosomal compartment where the antigens are proteolyzed. In contrast, polypeptides synthesized by cells are broken down to 8-10 residue peptides in the cytosol, transported into the ER, loaded onto class I MHC molecules and expressed on the cell surface for recognition by CD8+ T cells. We reasoned that alpha beta T cells lacking CD4 and CD8 coreceptors might recognize foreign antigens using antigen presenting molecules other than the classical MHC class I and II complexes. Here we characterize the antigen presenting pathway mediated by nonMHC encoded CD1 molecules. CD1 proteins consist of single heavy chains associated with beta2m thus resembling class I complexes. However, CD1 molecules present exogenously derived mycobacterial antigens via a chloroquine sensitive pathway. Surprisingly, the antigens presented are complex lipids displaying chromatographic characteristics typical of mycolic acids, a major component of the mycobacterial cell wall. Here we propose to purify and determine the fine structure of the bacterial lipids recognized by these alpha beta T cells. We examine critical steps in the assembly of CD1 proteins, including their interactions with the molecular chaperone calnexin, and with the invariant chain (Ii) that normally assembles with class II molecules. We test the hypothesis that Ii directs trafficking of newly synthesized CD1 molecules to intersect with endocytosed exogenously derived nonprotein antigens. We will determine if Ii plays an important role in antigen presentation by CD1 molecules by comparing recognition in Ii+ and Ii minus cells and confirm that recognition of the CD1-lipid antigen complex is TCR alpha beta mediated by conferring recognition by transfection of the TCR genes. Recognition of mycolic acid antigens recognized by T cells may be substantially more diverse than previously appreciated.

Agency
National Institute of Health (NIH)
Institute
National Institute of Allergy and Infectious Diseases (NIAID)
Type
Method to Extend Research in Time (MERIT) Award (R37)
Project #
5R37AI028973-11
Application #
2837409
Study Section
Allergy and Immunology Study Section (ALY)
Program Officer
Ridge, John P
Project Start
1989-12-01
Project End
1999-11-30
Budget Start
1998-12-01
Budget End
1999-11-30
Support Year
11
Fiscal Year
1999
Total Cost
Indirect Cost
Name
Brigham and Women's Hospital
Department
Type
DUNS #
071723621
City
Boston
State
MA
Country
United States
Zip Code
02115
Lynch, Lydia; Hogan, Andrew E; Duquette, Danielle et al. (2016) iNKT Cells Induce FGF21 for Thermogenesis and Are Required for Maximal Weight Loss in GLP1 Therapy. Cell Metab 24:510-519
Garg, Salil; Brenner, Michael B (2015) RNAi screens of lysosomal trafficking. Methods Cell Biol 126:119-38
Lynch, Lydia; Michelet, Xavier; Zhang, Sai et al. (2015) Regulatory iNKT cells lack expression of the transcription factor PLZF and control the homeostasis of T(reg) cells and macrophages in adipose tissue. Nat Immunol 16:85-95
Hu, Xinli; Kim, Hyun; Brennan, Patrick J et al. (2013) Application of user-guided automated cytometric data analysis to large-scale immunoprofiling of invariant natural killer T cells. Proc Natl Acad Sci U S A 110:19030-5
Brennan, Patrick J; Brigl, Manfred; Brenner, Michael B (2013) Invariant natural killer T cells: an innate activation scheme linked to diverse effector functions. Nat Rev Immunol 13:101-17
Tatituri, Raju V V; Watts, Gerald F M; Bhowruth, Veemal et al. (2013) Recognition of microbial and mammalian phospholipid antigens by NKT cells with diverse TCRs. Proc Natl Acad Sci U S A 110:1827-32
León, Luis; Tatituri, Raju V V; Grenha, Rosa et al. (2012) Saposins utilize two strategies for lipid transfer and CD1 antigen presentation. Proc Natl Acad Sci U S A 109:4357-64
King, Irah L; Fortier, Anne; Tighe, Michael et al. (2011) Invariant natural killer T cells direct B cell responses to cognate lipid antigen in an IL-21-dependent manner. Nat Immunol 13:44-50
Brigl, Manfred; Tatituri, Raju V V; Watts, Gerald F M et al. (2011) Innate and cytokine-driven signals, rather than microbial antigens, dominate in natural killer T cell activation during microbial infection. J Exp Med 208:1163-77
Garg, Salil; Sharma, Mahak; Ung, Cindy et al. (2011) Lysosomal trafficking, antigen presentation, and microbial killing are controlled by the Arf-like GTPase Arl8b. Immunity 35:182-93

Showing the most recent 10 out of 32 publications