Further probes into quantitative aspects of competitive binding assays: Allowance for effects of antigen multivalency in immunoassays

Hogg P.J. and Winzor D.J. (1987) Further probes into quantitative aspects of competitive binding assays: Allowance for effects of antigen multivalency in immunoassays. Archives of Biochemistry and Biophysics, 254 1: 92-101. doi:10.1016/0003-9861(87)90084-1


Author Hogg P.J.
Winzor D.J.
Title Further probes into quantitative aspects of competitive binding assays: Allowance for effects of antigen multivalency in immunoassays
Journal name Archives of Biochemistry and Biophysics   Check publisher's open access policy
ISSN 1096-0384
Publication date 1987-01-01
Sub-type Article (original research)
DOI 10.1016/0003-9861(87)90084-1
Volume 254
Issue 1
Start page 92
End page 101
Total pages 10
Subject 1303 Specialist Studies in Education
1304 Biophysics
1312 Molecular Biology
Abstract Effects of antigen multivalency on procedures for the analysis of immunoassays are examined on the basis of a theoretical expression developed in the context of quantitative affinity chromatography [Nichol, L. W., Ward, L. D., and Winzor, D. J. (1981) Biochemistry 20, 4856-4860] but which is also pertinent to antigen-antibody interactions that may be described in terms of a single intrinsic association constant. Quantitative relationships are generated which provide the basis for more rigorous logit-log analyses of radioimmunoassays in which the antigen is multivalent, and an additional, theoretically superior, linear transform of the basic expression is developed. Simulated binding data for a tetravalent antigen system are then used to demonstrate (i) the curvilinearity of the conventional Scatchard plot for such a system despite the homogeneity of binding sites, and (ii) the application of the various linear transforms involving logarithmic functions. Of particular interest in that regard is the observation that the traditional logit-log analyses yield linear plots with the predicted slope of unity even though antigen univalence is an implicit assumption in their application. Results obtained in a solid-phase radioimmunoassay of triiodothyronine are then presented to provide, for that system at least, experimental justification of the above-mentioned assumption that the antibody-antigen interactions may be described in terms of a single intrinsic association constant. Finally, an enzyme-linked immunoassay of ferritin is used to illustrate the possibility that a linear Scatchard plot may be obtained with a multivalent antigen under conditions where steric factors restrict participation of an antigen molecule to a single interaction with immobilized antibody.
Q-Index Code C1
Q-Index Status Provisional Code
Institutional Status Unknown

Document type: Journal Article
Sub-type: Article (original research)
Collection: Scopus Import
 
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