Zn/Cu superoxide dismutase autoantibody in cemented tungsten carbide workers.
Siegel-PD; Hettick-JM; Bledsoe-T; Law-BF; Sahakian-N
Toxicologist 2007 Mar; 96(1):240
Asthma and hard metal pneumoconiosis have been associated with exposure to aerosols containing nickel, cobalt, and tungsten in the cemented tungsten carbide industry. Only a few studies reported metal-specific IgE in sera of hard metal aerosol exposed workers, but antibody prevalence was very low. In the present study, sera from 140 cemented tungsten carbide workers were screened for specific IgG against chromium (Cr3+), copper (Cu2+), cobalt (Co2+), zinc (Zn2+) and nickel (Ni2+), haptenized to albumin (HSA) and superoxide dismutase (SOD). SOD was used as a protein carrier for haptenization, because its physiologically active form is Zn/Cu-SOD and it is an important endogenous antioxidant enzyme. Antigens were characterized using MALDI-TOF mass spectrometry (MS). Mass spectra of haptenized SOD showed 0-3 Co, 0-3 Zn, and 0-1 Ni ions bound per SOD molecule. Quantification of specific binding of Cu was not possible due to the large numbers of copper ions bound to SOD, consistent with non-specific binding. Haptenization to HSA was evident by color change resulting from binding of the metals to HSA. Specific chromium and cobalt IgGs were not found using either of the haptenized proteins. Casein was not sufficient to block non-specific IgG binding from 19 sera. These sera were re-screened using bovine serum albumin blocked ELISA plates. Within this subgroup, specific-IgG was found for Ni-SOD in one worker, and IgG specific to both Cu- and Zn-SOD was found in the sera of 10 workers. Anti-apo-SOD IgG was not found. This is the first report of autoantibody against Zn/Cu-SOD. It is not known if the 7.1% prevalence rate of anti-Zn/Cu- SOD IgG in this group of cemented tungsten carbide workers is excessive. The relationship of Zn/Cu-SOD autoantibody to reported respiratory symptoms and respiratory disease has not yet been established in this workforce.
Bronchial-asthma; Respiratory-system-disorders; Pulmonary-system-disorders; Metals; Aerosols; Metal-compounds; Metal-dusts; Metallic-dusts; Metallic-compounds; Respirable-dust; Pneumoconiosis; Hard-metals; Hard-metal-disease; Serological-techniques; Hard-metal-workers; Physiological-effects; Antibody-response; Proteins; Antigens; Antioxidants; Enzymes; Mass-spectrometry
16065-83-1; 7440-50-8; 7440-48-4; 7440-66-6; 7440-02-0
The Toxicologist. Society of Toxicology 46th Annual Meeting and ToxExpo, March 25-29, 2007, Charlotte, North Carolina