The TIM gene family was identified using a congenic mouse model in which polymorphisms in TIM-1 and TIM-3 wre associated with Th1-Th2 differentiation and allergen-induced ainway hyperreactivity (AHR) between BALB/c and congenic HBA mice. The long-term goals of Project 3 are to understand how the Tim genes regulate peripheral tolerance, adaptive immune responses, and allergy. In the previous grant period we showed that TIM-1 is an important costimulatory molecule for T cells, that TIM-1 and TIM-4 modulate 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 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 their recognition of PtdSer. These results together suggest a new paradigm for TIM proteins as PtdSer receptors that by regulating the recognition and clearance of apoptotic cells, can regulate tissue homeostasis, T cell responses and the induction of peripheral tolerance.
In Specific Aim 1 we will determine the mechanisms by which TIM-4 expressed on APC, and TIM-1, expressed on activated T cells and Th2 cells, regulate oral tolerance and prevent food allergy. We will examine mechanisms by which TIM-4 blockade inhibits oral tolerance induction.
In Specific Aim 2, we will characterize the cell types and APC subset(s) in the lamina propria and mesenteric lymph node that express TIM-4, the conditions that modulate expression of TIM-3 and TIM-4 following exposure to danger signals such as bacterial products that initiate food allergy. We will examine the consequences of T cell interaction with TIM-expressing APC on T cell subset differentiation.
In Specific Aim 3 we will investigate the role of TIM-3 polymorphic variants, which we have recently shown differ in recognition of apoptotic cells, in modulation of immune responses in BALB/c and HBA mice, and determine the roles of TIM-1 and TIM-3 in modulating the development of airway hyperreactivity in these strains. We have developed unique reagents that will enable us to accomplish these goals. We have generated panels of anti-TIM-1 and TIM-4 mAbs, we have generated TIM-4 and TIM-1 transgenic mice, and TlM-1 deficient mice are now breeding in our colony. Our laboratory has extensive experience in the study of tolerance as a mechanism that protects against Th2-driven immune responses and in the study of dendritic cells (DCs) and antigen-specific CD4+ Tpeg cells. These studies will greatly improve our understanding of immune regulation and lead to new therapies for inflammatory diseases.
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. Asthma and allergy (atopic diseases) affect up to 40% of the general population, and are major public health problems with limited therapies. We believe that further study of these molecules will greatly improve our understanding of disease mechanisms, and are likely to lead to novel therapies for asthma and food allergy.
|Kroy, Daniela C; Ciuffreda, Donatella; Cooperrider, Jennifer H et al. (2014) Liver environment and HCV replication affect human T-cell phenotype and expression of inhibitory receptors. Gastroenterology 146:550-61|
|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|
|Angiari, Stefano; Donnarumma, Tiziano; Rossi, Barbara et al. (2014) TIM-1 glycoprotein binds the adhesion receptor P-selectin and mediates T cell trafficking during inflammation and autoimmunity. Immunity 40:542-53|
|Recacha, Rosario; Jiménez, David; Tian, Li et al. (2014) Crystal structures of an ICAM-5 ectodomain fragment show electrostatic-based homophilic adhesions. Acta Crystallogr D Biol Crystallogr 70:1934-43|
|Gubin, Matthew M; Zhang, Xiuli; Schuster, Heiko et al. (2014) Checkpoint blockade cancer immunotherapy targets tumour-specific mutant antigens. Nature 515:577-81|
|Kim, Hye Young; Chang, Ya-Jen; Chuang, Ya-Ting et al. (2013) T-cell immunoglobulin and mucin domain 1 deficiency eliminates airway hyperreactivity triggered by the recognition of airway cell death. J Allergy Clin Immunol 132:414-25.e6|
|Albacker, L A; Yu, S; Bedoret, D et al. (2013) TIM-4, expressed by medullary macrophages, regulates respiratory tolerance by mediating phagocytosis of antigen-specific T cells. Mucosal Immunol 6:580-90|
|Jemielity, Stephanie; Wang, Jinyize J; Chan, Ying Kai et al. (2013) TIM-family proteins promote infection of multiple enveloped viruses through virion-associated phosphatidylserine. PLoS Pathog 9:e1003232|
|Manangeeswaran, Mohanraj; Jacques, Jerome; Tami, Cecilia et al. (2012) Binding of hepatitis A virus to its cellular receptor 1 inhibits T-regulatory cell functions in humans. Gastroenterology 142:1516-25.e3|
|Kim, Hye Young; Eyheramonho, Maria Belen; Pichavant, Muriel et al. (2011) A polymorphism in TIM1 is associated with susceptibility to severe hepatitis A virus infection in humans. J Clin Invest 121:1111-8|
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