Use of free radical chemistry in an immunometric assay for 17 beta-estradiol.
BACKGROUND
We wished to develop an enzyme immunometric assay for 17 beta-estradiol (E2) in human serum using solid-phase immobilized epitope immunoassay (SPIE-IA) technology and free radical chemistry.


METHODS
We used an anti-estradiol monoclonal antibody as capture antibody and Fenton-like reagents to cross-link it to E2. The same antibody, labeled with acetylcholinesterase, was used for detection. Serum was diluted 10-fold before assay.


RESULTS
After correction by the dilution factor, the detection limit was 5 ng/L for human serum and intra- and interassay CVs were <7% and 15%, respectively, at concentrations of 169-2845 ng/L. No cross-reactivity was seen with other natural steroids. In comparison with a competitive commercial RIA performed on 88 undiluted human sera, the slope (SD) of the regression line was 1.05 (+/- 0.02) and the intercept was 47 (+/-27) ng/L (S(y/x) = 186 ng/L) at concentrations of 20-5000 ng/L (r(2) = 0.97).


CONCLUSIONS
The use of Fenton-like chemistry in SPIE-IA technology allows a sensitive measurement of E2 in human serum and could be a new approach for the development of sensitive immunoassays.
Buscarlet
L
L
CEA, Laboratoire d'Etudes Radioimmunologiques, SPI/DRM/DSV, CEA/Saclay, 91191 Gif-sur-Yvette Cedex, France.
Volland
H
H
Dupret-Carruel
J
J
Jolivet
M
M
Grassi
J
J
Créminon
C
C
Taran
F
F
Pradelles
P
P
D000911:Antibodies, Monoclonal; D000975:Antioxidants / Q000737:chemistry; D019327:Copper Sulfate; D003429:Cross Reactions; D003432:Cross-Linking Reagents / Q000737:chemistry; D004492:Edetic Acid; D000939:Epitopes; D004958:Estradiol / Q000097:blood*; D005296:Ferrous Compounds; D005609:Free Radicals / Q000737:chemistry; D006801:Humans; D006861:Hydrogen Peroxide / Q000737:chemistry; D006863:Hydrogen-Ion Concentration; D007118:Immunoassay / Q000379:methods; D007501:Iron / Q000737:chemistry; D011863:Radioimmunoassay; D012044:Regression Analysis; D012680:Sensitivity and Specificity
D000911:Antibodies, Monoclonal; D000975:Antioxidants; D003432:Cross-Linking Reagents; D000939:Epitopes; C045076:Fenton's reagent; D005296:Ferrous Compounds; D005609:Free Radicals; C020748:ferrous sulfate; D004958:Estradiol; D004492:Edetic Acid; D006861:Hydrogen Peroxide; D007501:Iron; D019327:Copper Sulfate