Recombinant HLA-DP2 binds beryllium and tolerizes beryllium-specific pathogenic CD4+ T cells

Area of Science:

• Immunology
• Molecular Biology
• Occupational Health

Background:

• Chronic beryllium disease (CBD) is a lung disorder caused by beryllium exposure.
• CBD involves granulomatous inflammation and beryllium-specific CD4+ T cell accumulation in the lungs.
• The interaction between HLA-DP2, beryllium, and CD4+ T cells is crucial in CBD pathogenesis.

Purpose of the Study:

• To characterize the molecular interactions among HLA-DP2, beryllium, and CD4+ T cells.
• To investigate the role of HLA-DP2 in beryllium presentation to T cells.
• To explore potential therapeutic strategies for CBD.

Main Methods:

• Construction of recombinant HLA-DP2 and HLA-DP4 molecules.
• Peptide binding assays and 9Be nuclear magnetic resonance spectroscopy.
• T cell proliferation and cytokine secretion assays using beryllium-specific T cell lines and antigen-presenting cells (APCs).

Main Results:

• Beryllium binds to the engineered HLA-DP2 molecule but not HLA-DP4.
• Beryllium presentation to CD4+ T cells by fixed APCs was independent of antigen processing.
• Exposure to beryllium-pulsed HLA-DP2 induced T cell IFN-gamma secretion and blocked subsequent proliferation.
• Pre-exposure to beryllium-pulsed HLA-DP2 tolerized T cells.

Conclusions:

• Engineered HLA-DP2 molecules can present beryllium to specific T cells.
• These molecules can induce T cell tolerance, offering a potential therapeutic avenue for CBD.
• The findings provide a template for engineering HLA-DP2 variants for T cell tolerization without antigen exposure.