Bispecific enzyme-linked signal-enhanced immunoassay with subattomole sensitivity.
A bispecific enzyme-linked signal-enhanced immunoassay (BiELSIA) was developed with markedly increased sensitivity. Antimyosin, the detection antibody, was linked to the signal probespecific antibody. Probes consisted of diethylenetriamine pentaacetic acids attached to polylysine modified with up to seven or eight horseradish peroxidase (HRP) units. Each bispecific antibody bound two polymer probes, providing twice the signal. Using BiELSIA in a competitive inhibition immunoassay format with an average of 1.5, 3, 4.5, 6, and 7.5 HRP units per polymer-probe, the sensitivity of standard enzyme-linked immunosorbent assay (10(13) mole) was increased to 10(15), 10(18), 10(19), 10(20), and 10(-21) mol (< or = 1,000 molecules), respectively. BiELSIA detected cardiac myosin heavy chain fragments in sera of patients obtained at the time of emergency department admission for acute myocardial infarction, but not in normal sera. This technology should be applicable for detection of cancer, human immunodeficiency virus, prion, and other antigens that are present in concentrations too low for detection by current immunoassays.
The Center for Cardiovascular Targeting, Bouve College of Health Sciences, School of Pharmacy, Northeastern University, Boston, MA 02115, USA. b.khaw@neu.edu
Ban-An
BA
Khaw
Ram
R
Rammohan
Adham
A
Abu-Taha
D006330:Heart Defects, Congenital / Q000097:blood / Q000175:diagnosis; D006801:Humans; D007124:Immunoenzyme Techniques / Q000379:methods*; D009203:Myocardial Infarction / Q000097:blood / Q000175:diagnosis*; D018995:Myosin Heavy Chains / Q000097:blood*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity
D018995:Myosin Heavy Chains