Automated homogeneous liposome-based assay system for total complement activity.
We developed an automated homogeneous immunoassay, based on immune lysis of dinitrophenyl (DNP)-labeled liposomes, for measuring total complement activity. Liposome lysis caused by complement activity was detected spectrophotometrically from entrapped glucose-6-phosphate dehydrogenase activity. Complement activity in human sera was quantified by comparison with a calibration curve. For ease of application to fully automated routine clinical analyzers, we adopted a two-reagent system, one reagent containing a homogeneous population of small DNP-labeled liposomes and one containing antibody/substrate. This system required calibration only once a week. Within-run and between-run CVs were 0.4-1.3% (n = 10) and 1.8-4.7% (n = 10), respectively. Serum results were linear upon dilution (with saline) over a twofold range. Bilirubin, hemoglobin, Intrafat, and serum proteins such as rheumatoid factor, M protein, IgG, and IgA did not affect the assay results. The results (y) correlated well with those from a hemolytic complement activity test (x): y = 1.05x - 1.14, r = 0.92, on 66 samples in the range < 10- > 50 kU/L. This method should therefore be of great use for the determination of complement activity.
Yamamoto
S
S
Osaka Research Laboratories, Wako Pure Chemical Industries, Ltd., Hyogo, Japan.
Kubotsu
K
K
Kida
M
M
Kondo
K
K
Matsuura
S
S
Uchiyama
S
S
Yonekawa
O
O
Kanno
T
T
D000293:Adolescent; D000328:Adult; D000818:Animals; D001322:Autoanalysis / Q000379:methods* / Q000592:standards / Q000706:statistics & numerical data; D002138:Calibration; D003165:Complement System Proteins / Q000032:analysis*; D004136:Dinitrobenzenes; D005260:Female; D005954:Glucosephosphate Dehydrogenase / Q000032:analysis / Q000378:metabolism; D006801:Humans; D007202:Indicators and Reagents; D007700:Kinetics; D008081:Liposomes; D008297:Male; D008875:Middle Aged; D011786:Quality Control; D051381:Rats; D012016:Reference Values; D013053:Spectrophotometry
D004136:Dinitrobenzenes; D007202:Indicators and Reagents; D008081:Liposomes; D003165:Complement System Proteins; D005954:Glucosephosphate Dehydrogenase