Immunogenicity assays sensitivity

Position of spacer arm. The position of the linker group on the target analyte that connects it to the immunogen has a profound influence on the selectivity and sensitivity of the subsequent assays. The handle should be attached as far as possible from the unique determinant groups, allowing maximum exposure of the important... 

Figure 13 Structures of haptens used for immunizing and coating antigens in a monoclonal antibody-based immunoassay for diuron. A sensitive assay was developed using coating hapten I that had the handle in a position different from the immunogen hapten. When the oxygen in the urea moiety of hapten I was replaced with a sulfur (hapten 11), increasing the heterology, even greater sensitivity was achieved...

In summary, these are the clinically relevant questions about the immunogenicity of rDNA species-specific proteins will antibody be induced in the recipient that will neutralize the therapeutic effect or lead to immune complex disease What is the class (e.g., IgG or IgE) and specificity (i.e., reactivity against specific protein or contaminant) of the antibody induced The former antibody type could potentially neutralize the product and produce immune complex disease, while the latter could result in an anaphylaxis response. It is possible that the antibody induced is of insignificant health consequence, and its presence is known only because of improvements made in the sensitivity of detection methods with the introduction of the enzyme-linked immunosorbent (ELISA) assay. 

While the use of IgGl as an immunogenicity endpoint to attempt to predict the relative allergenicity of enzymes/proteins is open to criticism as mechanistically irrelevant, the true value of the method will lie in its performance relative to other preclinical test methods and human sensitization patterns. Many newly emerging methods in immunoloxicology rely on surrogate endpoints or endpoints that measure only a component of the response process (e.g. skin equivalent cultures for skin and eye irritation, local lymph node assay for contact sensitization, mouse IgE test for chemical respiratory sensitization). Their value lies in their... 

The optimization and validation of immunoassays for immunogenicity (ADA) testing has been described in detail in several publications [9,14,33,34]. In this section, we will describe the evaluation of relevant performance characteristics (validation parameters) that require the most effort. Some of these are different from the validation of traditional bioanalytical pharmacokinetic (PK) methods for macromolecules [35 37]. Precision, specificity, robustness, and ruggedness are determined similarly between ADA and PK methods. However, recovery/accuracy, sensitivity, stability, linearity, system suitability controls, and selectivity are treated differently between these two types of assays. 

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