Immunological studies of grain dust.
J Environ Pathol Toxicol 1979 May/Jun; 2(5):9-22
The mechanism of respiratory tract inflammation in grain elevator workers was investigated. Airborne and settled grain dust samples were collected from grain elevators in Minnesota and Wisconsin. Samples of ground whole rye extract also were obtained. The dusts and extract were added to normal human serum (NHS). The rate of conversion of the third component of complement (C3PA) to its activator form (C3A) was measured, along with total hemolytic activity of complement. Some NHS samples were treated with chelating agents prior to addition of the dusts or extract. The dusts also were tested with guinea pig serum that was deficient in the fourth component of complement (C4D). The dust and extract samples were tested for endotoxic content. Almost 47 percent of the dust particles were less than 5 microns in size. Conversion of C3PA to C3A and hemolytic consumption were dose dependent. The chelation tests indicated that complement activation occurred via the alternative pathway, rather than via the classical complement pathway. Dust activity in NHS correlated with that in C4D serum. No relationship was found between endotoxin concentrations and hemolytic toxicity of the dusts or extract. Airborne dusts were more toxic than settled dusts. The authors suggest that activation of the alternative complement pathway by grain dusts may be a factor in the respiratory response of exposed workers.
Grain-dust; Grain-elevators; Respiratory-system-disorders; Grain-elevator-workers; Metabolic-effects; Metabolic-processes; Biochemical-reactions; Serological-analysis; Antigen-antibody-reactions; Farm-machinery; Farm-equipment
Journal of Environmental Pathology and Toxicology. Toxicological and Carcinogenic Health Hazards in the Workplace: proceedings of the First Annual NIOSH Scientific Symposium, Cincinnati, Ohio, April 1978