Incidence and specificity of interference in two-site immunoassays.

Abstract Using a modified "two-site" immunoradiometric assay, termed an "interference assay," we have demonstrated the occurrence of non-analyte antibody-binding substances in approximately 40% of serum samples. These substances multivalently bind antibodies from any of several species at a site other than the antigen-binding site. Using a two-site immunoradiometric assay for human choriogonadotropin, we have investigated their effect on analyte quantification. In this system these antibody-binding substances mimic the presence of analyte; when analyte is actually present, they can also cause over- or underestimates. Addition of excess nonspecific immunoglobulin from an appropriate species eliminates this interference. However, the amount of nonspecific immunoglobulin added to an assay system may not always be enough to block interference in all samples.

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The preparation and properties of purified 125I-labelled antibodies to insulin

Biochemical Journal ◽

10.1042/bj1080611 ◽

1968 ◽

Vol 108 (4) ◽

pp. 611-618 ◽

Cited By ~ 63

Author(s):

L. E. M. Miles ◽

C. N. Hales

Keyword(s):

Binding Site ◽

Binding Capacity ◽

Antibody Binding ◽

Radioactive Material ◽

Antigen Binding ◽

Antigen Binding Site ◽

Simple Method ◽

Antibody Preparations

1. A procedure is described for the preparation of an insulin-immunoadsorbent containing 105–185mg. of insulin/g. of matrix, and with an antibody-binding capacity of 660mg./g. of insulin-immunoadsorbent. 2. Purified non-precipitating 125I-labelled antibodies were prepared by iodination of the antibodies while they were isolated on the insulin-immunoadsorbent in order to protect at least one antigen-binding site. 3. The radioactive antibody was simply and rapidly separated from other radioactive material and damaging reagents, and found to be up to 94% pure as judged by its reaction with insulin-immunoadsorbent and unfixed insulin. 4. The 125I-labelled antibody preparations had iodine contents of 0·5–64atoms/mol. of protein and specific radioactivities of 0·3–125mc/mg. of protein. 5. It is suggested that this is a simple method of producing a useful reagent.

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Faculty Opinions recommendation of Variants of the antibody herceptin that interact with HER2 and VEGF at the antigen binding site.

Faculty Opinions – Post-Publication Peer Review of the Biomedical Literature ◽

10.3410/f.1158476.618775 ◽

2009 ◽

Author(s):

Peter Colman ◽

Douglas Fairlie

Keyword(s):

Binding Site ◽

Antigen Binding ◽

Antigen Binding Site

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Uncommon structural motifs dominate the antigen binding site in human autoantibodies reactive with basement membrane collagen

Molecular Immunology ◽

10.1016/j.molimm.2016.07.004 ◽

2016 ◽

Vol 76 ◽

pp. 123-133 ◽

Cited By ~ 1

Author(s):

Mary H. Foster ◽

Elizabeth S. Buckley ◽

Benny J. Chen ◽

Kwan-Ki Hwang ◽

Amy G. Clark

Keyword(s):

Basement Membrane ◽

Binding Site ◽

Antigen Binding ◽

Antigen Binding Site ◽

Structural Motifs ◽

Basement Membrane Collagen ◽

Membrane Collagen

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A shared idiotype among human anti-Ro/SSA autoantibodies.

Journal of Experimental Medicine ◽

10.1084/jem.169.5.1583 ◽

1989 ◽

Vol 169 (5) ◽

pp. 1583-1588 ◽

Cited By ~ 5

Author(s):

K K Gaither ◽

J B Harley

Keyword(s):

Binding Site ◽

Heart Block ◽

Congenital Heart ◽

Congenital Heart Block ◽

Antigen Binding ◽

Normal Donor ◽

Neonatal Lupus ◽

Antigen Binding Site ◽

Fine Specificity ◽

Low Level

Idiotypes and antiidiotypes are thought to be important immune regulators and have provided clues for the origin and pathogenicity of autoantibodies. Many lupus and Sjögren's syndrome patients, as well as most neonatal lupus infants with congenital heart block or dermatitis, have antibodies to the ribonucleoprotein Ro/SSA, which is one of a group of RNA-protein autoantigens commonly found in human lupus sera. To characterize the fine specificity of anti-Ro/SSA antibodies, a rabbit antidiotypic serum was prepared against polyclonal affinity purified anti-Ro/SSA F(ab')2. The resulting antiidiotype, anti-Id-Rol, is specific for the F(ab')2 fraction of the anti-Ro/SSA immunogen and its binding to anti-Ro/SSA is inhibited by purified Ro/SSA. These data indicate that the Id-Rol epitope on anti-Ro/SSA is associated with the antigen binding site of these same antibodies. The Id-Rol idiotype was present by ELISA in 3 of 12 additional anti-Ro/SSA preparations from precipitin-positive donor sera and in anti-Ro/SSA from one normal donor with low level antibody. This is the first shared idiotype to be found in the human autoantibodies binding to this RNA-protein antigen. Idiotypic differences between anti-Ro/SSA autoantibodies have the potential to explain the variation in pathologic associations found in individuals who develop this autoantibody specificity.

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