Antibodies antigenic determinant

Antigen A molecule that is capable of binding to an antibody. Antigenic Determinant See Epitope. 

Definition of the association (or avidity) constant for such multivalent antibody—antigen reactions must consider not only the heterogeneity of the antibodies and the antigen determinant site(s), but also an apparent additive effect of binding two antigen molecules to a single antibody. Such effects lead... 

In some cases, the anionic POs adsorbed on chitin have similar antigenic determinants, but the plants belonging to different families - and even members of the same family - could have polysaccharide-specific POs with different structures. Thus, the majority of investigated species had anionic chitin-specific peroxidises, and these isoforms from potato Solcmaceae) and horseradish Brassicaceae) formed lines of precipitation with antibodies to wheat chitin-bound PO but not to anionic isoPO (Maksimov et al., 2000). However, protein extracts from several plants of Brassicaceae, Cucurhitaceae and Fahaceae formed precipitate with both the chitin-specific and anionic PO of wheat (Fig. 3). It was foimd that the greatest homology showed in plants and formed precipitation lines with the anionic PO of wheat (Tab. 2). 

Secondary antibody and determination. A secondary antibody labeled with an enzyme is added which binds to the primary antibody that is bound to the coating antigen. If the primary antibody were produced in a rabbit, an appropriate secondary antibody would be goat anti-rabbit immunoglobulin G (IgG) conjugated with horseradish peroxidase (HRP) (or another enzyme label). Excess secondary antibody is washed away. An appropriate substrate solution is added that will produce a colored or fluorescent product after enzymatic conversion. The amount of enzyme product formed is directly proportional to the amount of first antibody bound to the coating antigen on the plate and is inversely proportional to the amount of analyte in the standards. 

Covalent attachment of antibody molecules to liposomes can provide a targeting capacity to the vesicle that can modulate its binding to specific antigenic determinants on cells or to molecules in solution. Antibody-bearing liposomes may possess encapsulated components that can be used for detection or therapy (Figure 22.17). For instance, fluorescent molecules encapsulated within antibody-targeted vesicles can be used as imaging tools or in flow cytometry... 

Figure 22.17 Antibody-liposome conjugates may be used as targeting reagents for detection or therapeutic applications. The liposome may be constructed to contain fluorescent molecules for detection purposes or bioactive agents for therapy. The antibody component targets the complex for binding to specific antigenic determinants.

Figure 24.5 Streptavidin-coated gold particles can be used to detect biotinylated antibodies that are bound to specific antigenic determinants.

There is a continuing demand for fast and simple analytical methods for the determination of many clinical, biochemical and environmental analytes. In this respect, immunoassays and immunosensors that rely on antibody-antigen interactions provide a promising means of analysis owing to their specificity and sensitivity. High specificity... 

The nature of the antigenic determinant has been characterized in a male worker with occupational asthma from nickel [415, 416] the antibody recognized Ni2+ bound at the natural Cu2 + /Ni2+ transport site of human albumin. The interpretation was deduced from metal ion blocking experiments and from the good agreement obtained between the pH dependency of the formation of the Ni2 + -albumin complex and the antigen-antibody complex. It was suggested that the antibody interaction depended on a special structural feature of the interaction of Ni2 + with human serum albumin, and perhaps the ability to form an octahedral complex affords one explanation [417]. 

The production of MAbs offers investigators a homogenous collection of antibodies that could bind selectively to a specific antigenic determinant with the same affinity. In addition to protein isolation and diagnostic techniques, MAbs have contributed greatly to RIAs. 

Antibody affinity from the Latin, affinis = connected with, having things in common. In immunohistochemistry, antibody affinity determines the strength of binding of a monovalent antibody, such as Fab fragment, to one epitope, i.e., how tightly an antibody binds to its particular antigen. 

Epitope is an antigenic determinant (a part of a molecule to which an antibody binds), which is a biological structure or sequence, such as a protein or carbohydrate, that is recognized by the immune system and to which an antibody binds. 

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