Monoclonal antibodies competition ELISA

Enzyme labels are usually associated with solid-phase antibodies in the technique known as enzyme-linked immunosorbent assay (ELISA). There are several variants of this technique employing both competitive and non-competitive systems. However it is best used in combination with two monoclonal antibodies in the two-site format in which an excess of antibody is bound to a solid phase such as a test-tube or microtitre plate the test antigen is then added and is largely sequestered by the antibody (Figure 7.12). After washing... 

A series of monoclonal antibodies were generated that can bind dimetridazole (269) and other nitroimidazole drugs used in veterinary medicine. An extraction procedure was developed for these nitroimidazoles that is compatible with a competition ELISA method, based on binding of these antibodies to the drugs. As little as 1 ng of 269 could be detected in turkey muscle by this method552. 

Other anticoccidials for which immunoassays have been developed include the polyethers salinomycin and lasalocid, and the quinazoline drug halofuginone. Concern over the potential toxicity of salinomycin has led to development of two competitive ELISAs for detecting and measuring salinomycin residues in poultry tissues. In the first ELISA (96), 16 monoclonal antibodies were prepared and evaluated for their ability to produce a rapid and low-cost screening procedure for residues of salinomycin in poultry liver. In the second (97), the antibodies produced showed cross-reactivity with narasin but not with lasalocid, madura-... 

Halofuginone can be also analyzed in chicken serum by a competitive ELISA developed on the basis of monoclonal antibodies (99). In this study, a serum matrix effect that afforded a higher sensitivity for the detection of halofuginone in chicken serum than in assay buffer or in highly diluted serum was observed. The sensitivity of the ELISA improved when used in more concentrated serum. 

Competitive binding immunoassay (e.g., RIA) Enzyme-linked immunosorbent assay (ELISA) Immunoradiometric assay (IRMA) — dual monoclonal antibody assay Receptor binding assay Cell binding assay... 

ELISA, you will determine the titer of this antibody, as well as that of a monoclonal antibody against /3-galactosidase, called J1, that is derived from a mouse hybridoma cell line. Based on the titer of the J1 antibody, you will perform a competitive ELISA to determine the concentration of /3-galactosidase in an unknown solution. 

Monoclonal antibodies were obtained against atrazine and its metabolite hydroxyatrazine by immunizing mice with atrazine or hydroxyatrazine protein conjugates. By competitive ELISA, we observed that the antibodies raised against hydroxyatrazine cross-reacted mainly with hydroxypropazine. The antibodies raised against atrazine cross-reacted with propa-zine, prometone, prometryne, and to a much lower extent with a few other s-triazines and hydroxy-s-triazines. Atrazine could be detected in water samples down to 50 ppt. Average recoveries measured by ELISA from soil samples fortified with atrazine or hydroxyatrazine were comparable to those measured by GLC or HPLC. Soil samples of unknown atrazine content were analyzed by GLC, GC-MS, and by ELISA. The results show that the ELISA immunoassay represents a valuable detection method for trace amounts of atrazine and hydroxyatrazine in soil. 

Very recently we raised three monoclonal antibodies against human liver Mn-SOD. The epitope of one of these antibodies was found to be a COOH-terminal peptide, as judged by competitive inhibition assay using synthetic peptides (K4). Using this antibody we developed an ELISA method and found that the enzyme is also present in human serum. Measurement of the serum immunoreactive Mn-SOD protein levels in various diseases revealed that the enzyme levels are... 

Manager B, Solve M, Eriksen H, Brogen CH (1994). Bovine 3-lactoglobulin in hypoallergenic and ordinary infant formulas measured by an indirect competitive ELISA using monoclonal and polyclonal antibodies. Food Agric. Immunol, 6(l) 73-83. 

The primary alternative to the instrumental methods summarized above is immunodetection of EA with specific antibodies. Antiserum raised in response to immunization with lysergol (6a) coupled to human serum albumin recognizes several EA (100). Used for competitive enzyme-linked immunosorbent assay (ELISA), this broad-spectrum antiserum allows rapid detection of total EA in many samples concurrently. However, it does not separately quantify the different EA that contribute to the profile, and different EA show different reactivities to the antiserum. Monoclonal antibodies specific for individual EA species, such as ergotamine, also have been raised and provide an effective means for detection and quantification of the particular EA, as well as a valuable tool for physiological studies (101). 

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