The TIM gene family was identified using a congenic mouse model in which polymorphisms in TIM-1 and TIM-3 were associated with differences in Th1-Th2 differentiation and allergen-induced airway hyperreactivity (AHR) between BALB/c and congenic HBA mice. Our goal is to understand how the Tim genes regulate peripheral tolerance, adaptive immune responses, and allergy. We have shown that TIM-1 is an important costimulatory molecule for T cells, that TIM-1 and TIM-4 regulate T cell responses and the development of tolerance, and that TIM-1 and TIM-4 are receptors for phosphatidylserine (PtdSer), a key molecule for recognition and uptake of apoptotic cells. We have recently found that TIM-3, expressed on Th1 cells and APC, is also a receptor for PtdSer and that the allelic variants of TIM-3 associated with asthma differ in binding to PtdSer. These results suggest a new paradigm for TIM proteins as PtdSer receptors that by regulating the recognition, clearance, and response to apoptotic cells, can regulate T cell responses and the induction of peripheral tolerance. To understand how TIM protein recognition of PtdSer regulates immune responses, we propose to:
Specific Aim 1 : Determine the functional consequences of TIM-4 and TIM-3 on APC binding to phosphatidylserine on apoptotic cells. We will examine effects of apoptotic cell engulfment on DCs and macrophages including (a) anti-inflammatory mediator production: IL-10, TGF-B, IDO;(b) expression of co-inhibitory molecules;and (c) expression of co-stimulatory molecules. We will determine the effects of TIM-4- and TIM-3 mediated phagocytosis of apoptotic cell antigen on TReg and T helper subset development.
Specific Aim 2. Determine the structure/function relationship of TIM allelic variants on recognition of phosphatidylserine, phagocytosis, and T cell activation. We will determine if cells expressing HBA and BALB/c alleles of TIM-1 and TIM-3 have different capacities to recognize PtdSer and phagocytose apoptotic cells. We will determine how binding of PtdSer on an apoptotic cell to TIM-1 and TIM-3 on a T cell regulates T cell activation and TReg development, and compare BALB/c and HBA T cells.
Specific Aim 3 : Investigate the in vivo role of TIM-1 and TIM-3 allelic variants in immune responses and regulation of peripheral tolerance. We will compare the roles of the TIM-3 pathway in clearance of apoptotic cells in vivo and in the presentation of apoptotic cell-associated antigen in BALB/c and HBA mice. We will determine the relative roles of TIM-1 and TIM-3 in regulating the development of AHR in BALB/c and HBA mice. These studies will greatly increase our understanding of the function of TIMs in the regulation of T cell responses and tolerance, and characterize a novel and extremely important asthma susceptibility gene family.
The TIM genes have been shown to be important disease susceptibility genes (asthma, allergy, atopic dermatitis, rheumatoid arthritis) and to potently regulate immune responses and peripheral tolerance. TIM proteins recognize dead cells and help remove them from the body. Increased understanding of how TIM proteins regulate immune responses will allow us to design therapies for asthma, allergies, autoimmune disease and cancer.
|Chaudhri, Apoorvi; Xiao, Yanping; Klee, Alyssa N et al. (2018) PD-L1 Binds to B7-1 Only In Cis on the Same Cell Surface. Cancer Immunol Res 6:921-929|
|Kamphorst, Alice O; Wieland, Andreas; Nasti, Tahseen et al. (2017) Rescue of exhausted CD8 T cells by PD-1-targeted therapies is CD28-dependent. Science 355:1423-1427|
|Morales-Kastresana, Aizea; Telford, Bill; Musich, Thomas A et al. (2017) Labeling Extracellular Vesicles for Nanoscale Flow Cytometry. Sci Rep 7:1878|
|Derks, Sarah; Liao, Xiaoyun; Chiaravalli, Anna M et al. (2016) Abundant PD-L1 expression in Epstein-Barr Virus-infected gastric cancers. Oncotarget 7:32925-32|
|Foks, Amanda C; Engelbertsen, Daniel; Kuperwaser, Felicia et al. (2016) Blockade of Tim-1 and Tim-4 Enhances Atherosclerosis in Low-Density Lipoprotein Receptor-Deficient Mice. Arterioscler Thromb Vasc Biol 36:456-65|
|Kim, Hye Young; Umetsu, Dale T; Dekruyff, Rosemarie H (2016) Innate lymphoid cells in asthma: Will they take your breath away? Eur J Immunol 46:795-806|
|Mahoney, Kathleen M; Freeman, Gordon J; McDermott, David F (2015) The Next Immune-Checkpoint Inhibitors: PD-1/PD-L1 Blockade in Melanoma. Clin Ther 37:764-82|
|Mahoney, Kathleen M; Rennert, Paul D; Freeman, Gordon J (2015) Combination cancer immunotherapy and new immunomodulatory targets. Nat Rev Drug Discov 14:561-84|
|Derks, Sarah; Nason, Katie S; Liao, Xiaoyun et al. (2015) Epithelial PD-L2 Expression Marks Barrett's Esophagus and Esophageal Adenocarcinoma. Cancer Immunol Res 3:1123-1129|
|Xiao, Yanping; Yu, Sanhong; Zhu, Baogong et al. (2014) RGMb is a novel binding partner for PD-L2 and its engagement with PD-L2 promotes respiratory tolerance. J Exp Med 211:943-59|
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