Basu A, Nara S, Chaube SK, Rangari K, Kariya KP, Shrivastav TG. The influence of spacer-containing enzyme conjugate on the sensitivity and specificity of enzyme immunoassays for hapten.
Clin Chim Acta 2006;
366:287-92. [PMID:
16337168 DOI:
10.1016/j.cca.2005.10.024]
[Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2005] [Revised: 10/28/2005] [Accepted: 10/29/2005] [Indexed: 11/30/2022]
Abstract
BACKGROUND
In hapten enzyme immunoassays (EIA), there is an increase or decrease of labeled hapten recognition by antibody that affects sensitivity of the assay. We incorporated a spacer between a hapten derivative and enzyme to test its influence on the sensitivity and specificity of enzyme immunoassays.
METHOD
Antibodies were generated against cortisol-3-O-carboxymethyl-oxime-bovine serum albumin (cortisol-3-O-CMO-BSA) and cortisol-21-hemisuccinate-bovine serum albumin (cortisol-21-HS-BSA) as an immunogen. Four cortisol horseradish peroxidase (HRP) enzyme conjugates were prepared using 2 cortisol derivatives (cortisol-3-O-CMO and cortisol-21-HS) with and without adipic acid dihydrazide (ADH) as a spacer. Eight combinations of homologous and heterologous assays were evaluated.
RESULT
The incorporation of ADH spacer in cortisol-enzyme conjugate improved the sensitivity in heterologous (bridge and site plus bridge) EIA systems. In heterologous assays (site plus bridge), the presence of spacer in enzyme conjugate reduced the cross-reactivity with cross-reacting steroids.
CONCLUSION
Spacer in the enzyme conjugate for hapten ELISA can improve the sensitivity of heterologous assay of hapten-like steroids. It may also reduce the cross-reactivity for some assays.
Collapse