Antibody binding affinity

NH Chiem, DJ Harrison. Monoclonal antibody binding affinity determined by microchip-based capillary electrophoresis. Electrophoresis 19 3040-3044, 1998. 

Monoclonal antibody-binding affinity was determined by microchip-based capillary electrophoresis with LIF detection (33). The mixing was carried out off-chip, and the on-chip separations were performed in less than 60 s (Fig. 9). A Scatchard plot analysis resulted in an affinity constant for the monoclonal anti-BSA antibody to fluorescently labeled BSA (BSA ) of... 

As many B cell epitopes are described to be conformational (Aalberse, 2000), peptides identified by sequential approaches may render limited information and might exhibit reduced antibody-binding affinity. In a very stringent definition, conformational epitopes are composed of amino acids from different loci in the allergen sequence brought into proximity by the tertiary structure of the protein. Systematic characterization of conformational epitopes is much more difficult compared to linear epitopes, because it requires knowledge of the 3D structure, which is often limited. 

Two parameters describe the physicochemical characteristics of antigen-antibody binding affinity and avidity. In a simplified system consisting of an... 

Estrada, E. (2003a) Application of a novel graph-theoretic folding degree index to the study of steroid-DB3 antibody binding affinity. Comp. Biol. Chem., 27, 305-313. 

The radioimmunoassay system itself, in which can be distinguished permanent factors the parameters of antibody binding (affinity, specificity), the relative affinity of the competitors for the antibody sites, and the experimental conditions and separation of bound and free, and contingent factors related to individual assays, material present in the biological fluids or introduced or concentrated during the purification procedures. 

Humanized recombinant anti-IL-2 receptor antibodies (Basiliximab, Simulect , and Daclizumab Zenapax ). These antibodies bind with high affinity to the IL-2 receptor on T-lymphocytes and prevent activation and clonal expansion of anti-allograft T-lymphocytes by endogenous IL-2. They are used to prevent kidney allograft rejection. The main side effect is immunosuppression. 

Fig. 11a,b. Binding affinities of IgG, IgM, and the antibody dendrimer (Gl) with the cationic porphyrin (TMPyP) (a) and those with the anionic porphyrin (TCPP) (b) estimated by ELISA... 

Cacia, J., Keck, R., Presta L. G., and Frenz, J., Isomerization of an aspartic acid residue in the complementarity-determining regions of a recombinant antibody to human IgE identification and effect on binding affinity, Biochemistry, 35, 1897, 1996. 

In a direct immunoassay the immobilized antibody binds to the corresponding antigen. The competitive immunoassay relies upon the competition of the analyte with a labelled analyte for antibody binding. These formats are widely used for high throughput affinity arrays. A sandwich immunoassay is based on the trapping or capture of the analyte by another antibody. In ELISA (enzyme linked immunosorbent assays) the second antibody is conjugated with an enzyme. The bound enzyme labelled antibody is detected by its ability to break down its substrate to a colored product. 

The conformation and orientation of adsorbed proteins has been examined with monoclonal antibodies that recognize a specific site in a protein of interest. Keselowsky et al. examined the conformation of Fn adsorbed to SAMs that carried methyl, hydroxyl, carboxyl, and amine groups [79]. They used monoclonal antibodies that recognized the central cell-binding domain of Fn near the RGD motif. Different SAM functionalities differentially modulated the binding affinities of the monoclonal antibodies (OH > COOH = NH2 > CH3). The strength of cell adhesion to these... 

The binding affinity between an antibody (Ab) and an antigen (Ag) can generally be described by the equilibrium expression ... 

There are many other examples of competitive electrochemical immunoassays and immunosensors for detecting clinically important analytes [12-14], Despite simplicity, a disadvantage of competitive immunoassays is that labeling the analyte may reduce, or totally remove, its binding affinity for antibody. This would occur if the analyte were labeled at a site that is closely associated with an epitope. 

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