The overall goal of this application is to understand the role of oxidative stress in chronic beryllium disease (CBD). CBD is an inflammatory hypersensitivity lung disease that continues to occur in 10% of the estimated 800,000 beryllium-exposed workers in the United Sates and is characterized by the presence of non-caseating granulomas with accumulation of macrophages and beryllium specific CD4+ T lymphocytes. Upon beryllium stimulation in vitro, these T cells proliferate and produce Th1 cytokines (i.e. TNF-alpha, INF-gamma, and IL-2) at unusually high levels. The precise molecular mechanism(s) by which beryllium regulates the production of these high levels of cytokines is unknown. It is hypothesized that oxidative stress enhances the APC's ability to present beryllium antigen to T cells, which may, in part, explain both the excessive cytokine response and associated lung granuloma formation. Exciting preliminary studies indicate that the redox status of the antigen presenting cell (APC) affects the T cell's response and may help explain why only a portion of the people exposed to beryllium actually develop CBD. The presence of APCs expressing class II molecules is required for CD4+ T cells from CBD patients to proliferate in the presence of beryllium in vitro. This project will use a modification of the clinical beryllium lymphocyte proliferation test (BeLPT) to examine the effect of redox balance on beryllium antigen presentation. This system will enable the testing of the hypothesis that oxidative stress affects the APC's ability to present beryllium antigen to T cells and the role of oxidative stress in modulating T cell activation. The hypothesis is addressed by the AIMS: (1) examine the effect of beryllium on APC and T cell antioxidant status and stimulation response; (2) examine the effect of altered APC glutathione status on beryllium antigen presentation; (3) examine the effect of altered oxidant status on beryllium antigen presentation by APC and T cell activation. Primary endpoints measured are (1) glutathione and enzymes involved in its synthesis and utilization; (2) markers of lipid, protein and DNA oxidation; and (3) T cell proliferation and Th1 cytokine release and accessory molecule expression. It is proposed that beryllium, itself; initiates oxidative stress in the APC and also serve as the antigen. Inherent differences in either resting APC antioxidant status or APC oxidant response to beryllium are predicted to be critical factors in determining whether people exposed to beryllium go on to develop CBD. These studies have the potential to further define the etiology of CBD, risk factors, and suggest novel approaches to prevent and treat this disease.
