Chronic beryllium disease (CBD) is a granulomatous lung disorder caused by beryllium exposure in the workplace and is characterized by the accumulation of beryllium-specific CD4+ T cells in the lung. Due to its unique chemical and physical properties, beryllium continues to be utilized in high-technology industries. Thus, CBD remains an important public health concern with more than 1,000,000 US workers having been exposed to beryllium and at risk for disease development. With the presence of a known antigen and an accessible target organ, CBD is an important model of immune-mediated, organ destruction. We and others have shown that the most important HLA molecule for beryllium presentation is HLA-DP. Using fibroblasts expressing mutated HLA-DP2 molecules, beryllium recognition was dependent on the glutamic acid residue at position 69 (?Glu69) of the HLA-DP ?-chain. In addition, T cell recognition of beryllium occurred in the absence of antigen processing, and nuclear magnetic resonance definitively showed that soluble HLA-DP2 directly bound beryllium. The goals of the studies in the current application are to elucidate the mechanism by which beryllium-specific CD4+ T cells recognize beryllium in the context of HLA-DP2 and to demonstrate the stability of the beryllium-specific memory T cell pool. The most likely possibilities of how ?Glu69 influences beryllium recognition are that 1) beryllium directly binds to the carboxylate of ?Glu69 in HLA-DP2 molecules, with peptide(s) only required to complete the ??TCR ligand or that 2) the effect of ?Glu69 on beryllium presentation is indirect through its influence on the repertoire of peptides that can bind to DP2, among which are peptides that can present beryllium. Our preliminary data favor the first hypothesis and suggest that we can study beryllium binding to HLA-DP2 prior to knowing which peptides are important for T cell recognition of the DP2- peptide/Be2+ complex. The first specific aim will provide definitive proof of beryllium binding with x-ray crystallography of HLA-DP2 with and without beryllium. The generation of HLA-DP2 mutants in the second aim will serve as a functional correlate to the structural studies in Aim #1.
The third aim will delineate which peptides are required to complete the ??TCR ligand while the final specific aim will determine whether progression from beryllium sensitization to disease is associated with an increased frequency of beryllium- specific CD4+ T cells in blood. Together, these studies will strengthen our understanding of how antigens cause granulomatous inflammation and specifically how metal antigens trigger an immune response. In addition, they will potentially allow the development of biomarkers to predict disease progression in high-risk subjects.

Public Health Relevance

This translational study will utilize blood and lung specimens from human subjects with an occupational lung disorder to further our understanding of the beryllium-induced immune mechanisms that lead to disabling lung dysfunction. In a disease characterized by progressive loss of lung function, the identification of potential biomarkers of disease progression will greatly advance the welfare of this patient population.

Agency
National Institute of Health (NIH)
Institute
National Heart, Lung, and Blood Institute (NHLBI)
Type
Research Project (R01)
Project #
5R01HL062410-13
Application #
8197361
Study Section
Hypersensitivity, Autoimmune, and Immune-mediated Diseases Study Section (HAI)
Program Officer
Eu, Jerry Pc
Project Start
1998-07-15
Project End
2013-11-30
Budget Start
2011-12-01
Budget End
2012-11-30
Support Year
13
Fiscal Year
2012
Total Cost
$379,358
Indirect Cost
$119,122
Name
University of Colorado Denver
Department
Internal Medicine/Medicine
Type
Schools of Medicine
DUNS #
041096314
City
Aurora
State
CO
Country
United States
Zip Code
80045
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Mack, Douglas G; Falta, Michael T; McKee, Amy S et al. (2014) Regulatory T cells modulate granulomatous inflammation in an HLA-DP2 transgenic murine model of beryllium-induced disease. Proc Natl Acad Sci U S A 111:8553-8
Bowerman, Natalie A; Falta, Michael T; Mack, Douglas G et al. (2014) Identification of multiple public TCR repertoires in chronic beryllium disease. J Immunol 192:4571-80
Dai, Shaodong; Falta, Michael T; Bowerman, Natalie A et al. (2013) T cell recognition of beryllium. Curr Opin Immunol 25:775-80
Falta, Michael T; Pinilla, Clemencia; Mack, Douglas G et al. (2013) Identification of beryllium-dependent peptides recognized by CD4+ T cells in chronic beryllium disease. J Exp Med 210:1403-18
Chain, Jennifer L; Martin, Allison K; Mack, Douglas G et al. (2013) Impaired function of CTLA-4 in the lungs of patients with chronic beryllium disease contributes to persistent inflammation. J Immunol 191:1648-56
Martin, Allison K; Mack, Douglas G; Falta, Michael T et al. (2011) Beryllium-specific CD4+ T cells in blood as a biomarker of disease progression. J Allergy Clin Immunol 128:1100-6.e1-5
Bowerman, Natalie A; Falta, Michael T; Mack, Douglas G et al. (2011) Mutagenesis of beryllium-specific TCRs suggests an unusual binding topology for antigen recognition. J Immunol 187:3694-703
Simonian, Philip L; Wehrmann, Fabian; Roark, Christina L et al. (2010) ?? T cells protect against lung fibrosis via IL-22. J Exp Med 207:2239-53
Dai, Shaodong; Murphy, Guinevere A; Crawford, Frances et al. (2010) Crystal structure of HLA-DP2 and implications for chronic beryllium disease. Proc Natl Acad Sci U S A 107:7425-30

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