Ultrasensitive time-resolved fluorescence method for alpha-fetoprotein.
We have examined the maximum sensitivity of a newly developed and optimized time-resolved fluorescence immunoassay system. The system, originally described elsewhere (Clin Biochem 1988:21:139-50), has undergone significant improvements in sensitivity through improvements of the labeled reagent used. We have chosen an alpha-fetoprotein (AFP) assay as a model and used monoclonal "capture" antibodies and monoclonal or polyclonal biotinylated antibodies in "sandwich-type" assay configurations. Streptavidin labeled with the europium chelator 4.7-bis(chlorosulfophenyl)-1,10-phenanthroline-2.9-dicarboxylic acid was used for detection. We can measure as few as 3 x 10(5) molecules of AFP with the optimized system. We have applied this assay to measure AFP in the serum of normal individuals after a 10-fold sample dilution. We conclude that this system is extremely sensitive and can be used in immunoassay or other applications where biotinylated reagents can be applied.
Department of Clinical Biochemistry, Toronto Western Hospital, Ontario, Canada.
T K
TK
Christopoulos
E S
ES
Lianidou
E P
EP
Diamandis
D000328:Adult; D000911:Antibodies, Monoclonal; D001426:Bacterial Proteins; D001710:Biotin; D005260:Female; D015200:Fluoroimmunoassay; D006801:Humans; D007106:Immune Sera / Q000032:analysis; D008297:Male; D008875:Middle Aged; D008954:Models, Biological; D019809:Streptavidin; D000509:alpha-Fetoproteins / Q000032:analysis* / Q000276:immunology
D000911:Antibodies, Monoclonal; D001426:Bacterial Proteins; D007106:Immune Sera; D000509:alpha-Fetoproteins; D001710:Biotin; D019809:Streptavidin