Conversion of C3 and consumption of hemolytic complement by extracts of airborne grain dust.
Olenchock-SA; Mull-JC; Major-PC
Chest 1979 Feb; 75(2):225-227
The effects of aqueous extractions of airborne grain dust on human C3 and hemolytic complement were studied. The involvement of the calcium independent alternative complement pathway in C3 conversion was investigated by differential chelation of magnesium and calcium with ethylenediamine-tetracetic-acid (60004) (EDTA) or ethyleneglycol-bis-(beta-amino-ethyl-ether)-N,N'-tetraacetic-acid (67425) (EGTA). Airborne oat and spring wheat dusts were obtained and dust extracts were mixed with normal human serum. The resulting hemolytic complement and functional C3 concentrations were compared with untreated normal human serum. Increasing amounts of dust extracts caused increasing conversion of C3 to C3b. Spring wheat dust extract was much more toxic to hemolytic complement activity than the extract of oat dust. Differential chelation revealed that serum with only chelator calcium or C1 did not convert C3 to C3b. Sera pretreated with EDTA and reacted with grain extracts blocked C3 conversion whereas those serums treated with EGTA demonstrated arc conversion from C3 to C3b. The authors suggest that the alternative complement pathway is involved in C3 conversion by grain dust extracts.
NIOSH-Author; Plant-dusts; Hematology; Humans; Chelates; Blood-serum; Biochemical-analysis; Biochemistry