title: In vitro activation of the alternative pathway of complement by settled grain dust.
abstract: Settled grain dust was collected from several active grain elevators in the Superior-Duluth areas of the United States. Particle size distribution (47% less than 5 micrometer) and endotoxin contamination (429 ng/gm) of the dust were similar to those reported for the airborne parent dust. Human complement uas activated in vitro in a dose-response manner which could be quantified. This hemolytic consumption was via the alternative pathway as defined by ethylenediaminetertraacetic acid/ethylene-glycol-bis-(beta-amino-ethyl ether) N,N'-tetraacetic acid (EDTA/EGTA) differential serum chelation, factor B conversion, and complement reductions in serum from guinea pigs deficient in C4. It is proposed that continuous low-dose exposure to aerosolized, biologically active rafter dust could contribute to the respiratory insult of grain workers.
mesh_terms: D003167:Complement Activation; D003170:Complement Pathway, Alternative; D004391:Dust; D002523:Edible Grain; D008033:Limulus Test
chemical_list: D004391:Dust