Quantitative measurement of SC5b-9 and C5b-9(m) in infarcted areas of human myocardium.
Previous immunohistochemical work has indicated that terminal C5b-9 complement complexes are selectively deposited in infarcted areas of human myocardium. In the present study, we sought to quantify C5b-9 levels in myocardial tissue, and to differentiate between the membrane-bound C5b-9 (m) and the cytolytically inactive SC5b-9 complex. Paired tissue specimens from infarcted and non-infarcted myocardium were obtained from 36 autopsies. The homogenized and washed tissues were extracted with n-octyl-beta-D-glucopyranoside (octylglucoside) detergent, and the concentrations of C5b-9 in the extracts were determined by ELISA. Membrane-derived C5b-9 (m) and SC5b-9 were differentiated from each other on the basis of their characteristic sedimentation behaviour in sucrose density gradients. It was found that infarcted myocardial tissue contained on average an approximately three-fold higher concentration of C5b-9, compared with non-infarcted tissue. This increase was due in part to an increase in levels of C5b-9 (m). The results corroborate previous immunohistochemical data and show that complement activation occurs to completion with the generation of potentially cytotoxic C5b-9 complexes in infarcted myocardial tissues.
Hugo
F
F
Institute of Medical Microbiology, University of Giessen, West Germany.
Hamdoch
T
T
Mathey
D
D
Schäfer
H
H
Bhakdi
S
S
D000328:Adult; D000368:Aged; D001344:Autopsy; D015938:Complement Membrane Attack Complex / Q000032:analysis*; D003165:Complement System Proteins / Q000032:analysis*; D004797:Enzyme-Linked Immunosorbent Assay; D006023:Glycoproteins / Q000032:analysis*; D006801:Humans; D008875:Middle Aged; D009203:Myocardial Infarction / Q000503:physiopathology*; D009206:Myocardium / Q000032:analysis
D015938:Complement Membrane Attack Complex; D006023:Glycoproteins; C047610:SC5b-9 protein complex; D003165:Complement System Proteins