Enzyme-linked immunosorbent assay characteristics

In order to compare the specific activity of plant-derived C5-1 to that of the hybridoma-derived antibody, the antigen-binding capacity of antibodies produced in each system was assayed by enzyme-linked immunosorbent assay (ELISA). As shown in Table 1.2, antibodies from both sources demonstrated similar binding characteristics against human IgGs [8]. Furthermore, the stability of alfalfa-derived C5-1 in the blood stream of Balb/c mice was comparable to that of the hybridoma-derived IgG [8]. 

Enzyme-linked immunosorbent assay is a heterogenous immunoassay. Reactions involve a solid phase to which components are sequentially presented and successively bound. This method is very effective in the determination of the total alkaloid content. The positive characteristics of this method are the use of non-toxic reagents and basic equipment with low costs, a small sample volume and the ability to measure alkaloids in crude sample extracts. According to the literature, compared with results obtained from GLC, the precision of ELISA for quinolizidine alkaloids is not as high as that of the gas chromatography procedure, but is adequate for plant breeding purposes. The use of enzymes in developing the methods of quinolizidine alkaloids analysis looks likely to increase in the future. 

An example of an immunoassay is the enzyme-linked immunosorbent assay (ELISA), which uses 96-well plates with antibodies bound on the sides of the wells. The characteristic of interest is the binding constant for the immunoreaction, which is defined as the association constant between antibody and antigen. It is important to generate a good antibody with strong binding. 

Microwave heat-assisted enzyme-linked immunosorbent assay (ELISA) has been used for measuring anti-glomerular basement membrane (GBM) antibodies in kidney serum (Van Dorp et al., 1991) The presence of GBM antibodies is one of the characteristics of Goodpasture s syndrome. The application of microwave heating reduces the duration of incubation to assay circulating anti-GBM autoantibodies. 

Clark, F. M. and Adams, A. M. (1977) Characteristics of the microplate method of enzyme-linked immunosorbent assay for the detection of plant viruses. J. Virol. Methods 34,475-483. 

Rubio, F.M., J.A. Itak, A.M. Scutellaro, M.Y. Selisker, and D.P. Herzog (1991). Performance characteristics of a novel magnetic-parti-cle-based enzyme linked immunosorbent assay for the quantitative analysis of atrazine and related triazines in water samples. Food Agric. Immunol., 3 113-125. 

After more than two decades, advances in IHC have provided a feasible approach to performing immunostain-ing on routinely processed tissues, such that this method is now routine for the performance of IHC special stains in surgical pathology laboratories using EEPE tissues (see Appendix lA). However, demands for improved reproducibility and for quantification have led to a growing recognition that IHC has the potential to be more than just a special stain. If properly controlled in all aspects of its performance, IHC can provide a tissue-based immunoassay with the reproducibility and quantitative characteristics of an ELISA (enzyme-linked immunosorbent assay) test, which not only detects the presence of an analyte (protein or antigen) but also provides an accurate and reliable measure of its relative or real amount (see Quality Control and Standardization section). 

This is directly proportional to the quantity of analyte present. This technique advanced rapidly when monoclonal antibodies became available, since this made it possible to produce unlimited quantities of antibodies with clearly defined characteristics [20]. This second type of assay is also known as a sandwich immunoassay, and is best suited to the assay of proteins rather than haptens. The widespread ELISA (Enzyme Linked Immunosorbent Assay) test belongs to this category [21-24]. 

SPR offers several advantages over conventional techniques such as fluorescence or enzyme-linked immunosorbent assay. Here the analyte does not require any special characteristics or labels and can be detected directly the measurements can be performed in real time to collect kinetic data it is a versatile technique, capable of detecting analytes over a wide range of molecular weights and binding affinities. Because of its unique features, SPR has become a powerful tool for studying biomolecular interactions. 

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