sepharose and Empyema

The possibility of direct inactivation of C3 by granular enzymes from polymorphonuclear leukocytes (PMNLs) in pleural empyema was examined. As a group, pleural empyema from 10 patients with purulent effusions and a positive bacteriologic culture cleaved significantly more 125I-labeled C3 bound to Sepharose (18.4% +/- 7.3%) than did 19 sterile pleural effusions (2.4% +/- 0.9%; P less than 0.001) and sonicates from bacterial strains commonly found in empyema (1.4% +/- 0.2%). Granular enzymes from 7 X 10(6) PMNLs cleaved 78.5% of 125I-labeled C3 bound to Sepharose. When proteolysis of 125I-labeled C3 after incubation with pleural empyema or PMNL granular enzymes was examined with polyacrylamide gel electrophoresis, breakdown products were similar. Granulocyte elastase-like activity was detected in four samples of pleural empyema. Granulocyte elastase inhibitors, as well as 10% human serum, effectively suppressed cleavage of C3 and elastase-like activity. In pleural empyemas, granula enzymes from PMNLs, especially elastase, apparently contribute to low complement-mediated opsonic activity by direct inactivation of C3.

Topics: Adult; Aged; Complement C3; Complement C3b Inactivator Proteins; Complement C3d; Complement Factor H; Edetic Acid; Empyema; Female; Granulocytes; Humans; Male; Middle Aged; Neutrophils; Peptide Hydrolases; Phenylmethylsulfonyl Fluoride; Pleural Effusion; Protease Inhibitors; Sepharose