Haptens, definition

A definite volume of the sample containing the hapten to be measured is added to the reaction test-tube,... 

Cross-reactivity The amount of a similar substance that will cause the same displacement of labelled antigen from the antibody as an arbitrary amount of the antigen. The usual definition is ID50, which is the concentration of cross-reacting material required to displace 50% of labelled hapten from the antibody. 

Since the components of each set were eluted by the same hapten group, galactose or lactose, and each protein combines with the same structural unit of the antigen, the individual proteins of each set have been designated as isoantibodies. This definition is a more restrictive definition of an isoantibody than is employed by immunologists (32) but is in line with the terminology employed by enzymologists for multi-molecular forms of enzymes (33). 

A detailed discussion of antibody production and its control is beyond our purpose. However, minimal appreciation of the events leading to antibody production and a few definitions are necessary if immunochemical techniques are to be used knowledgeably. An antigen may be defined as any compound that (1) can stimulate production of antibodies when injected into a test animal and (2) reacts specifically with the antibodies produced. Both parts of this definition are necessary to distinguish antigens from haptens (see Figure 8-3), which are small molecules that... 

No definitive study of the effects of protein carrier on response is available, and many carrier proteins have been used, including globulins, albumin, hemocyanin, thyroglobulin, and fibrinogen. The optimal number of haptens, or the epitope density, is also controversial, but a density of 8 to 25 haptens per bovine serum albumin molecule is probably optimal (12),... 

This technique resembles the formation of antibodies from haptens, and actually a similar mechanism to the imprinting was formerly thought to be the mechanism of formation of antibodies [29], The functional groups in these cavities are located at various points in the polymer chain, and are held in a definite mutual orientation simply by the crosslinking. In this case, the stereochemical information is not carried by a low-molec-... 

In the great majority of examples of MIA, the organometaUic tracers used are molecules derived from the analyte to be assayed (structures shown in Table 8.1) to which an organometallic moiety has been attached. The analyte is normally a hapten (cf. definition above). 

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