Antiserum, enzyme immunoassay

A competitive enzyme immunoassay for the quantification of ivermectin residues in bovine liver has also been reported recently (85). This method uses a polyclonal antiserum raised in rabbits against 5-O-succinoylivermectin-trans-ferrin conjugate. Cross-reactivity was demonstrated with doramectin, a member... 

A sensitive enzyme-immunoassay for plasma or saliva testosterone uses testosterone-lla-hemisuccinate antiserum, bound to cellulose to provide a solid phase for convenient separation. Testosterone-horseradish peroxidase conjugate was employed as the label.Another enzyme-immunoassay for testosterone employs a testosterone-3-(0-carboxymethyloxime)-pencillinase conjugate for competitive binding to the testosterone antiserum. 21-Amino-ll/3,17o -dihydroxypregn-4-ene-3,20-dione ( Cortisol 21-amine ) linked to alkaline phosphatase has been used ° in an effective enzyme-immunoassay for cortisol. 

Figure 2. Standard curves for a. polyclonal antiserum-based radioimmunoassay and b. polyclonal antiserum-based and monoclonal antibody-based enzyme immunoassays (PcAb EIA and McAb EIA, respectively).

The testosterone enzyme immunoassay was a solid phase double antibody competitive inhibition assay with horseradish peroxidase linked to testosterone-3-CMO. The testosterone antiserum was generated in rabbits against 4-androsten-ll-a-17-p-diol-3-one-ll-hemisuccinate bovine serum albumin. Cross reaction of the antiserum was as follows 17-p-hydroxyl-4,6-androstandien-3-one (60%), 5-a-androstan-17-p-ol-3-one (52%), 19-... 

Mild conjugation reactions have been used in an enzyme-linked immunoassay for detecting cephalexin residues in milk, hen tissues, and eggs. The assay was a double-antibody separation procedure based on use of a rabbit antiserum... 

The TRH radio-immunoassay was developed as a double antibody assay, with modifications mainly depending on the antiserum used, and on the conditions of incubation. Addition of an enzyme inhibitor to the assay tubes is essential to avoid degradation of TRH in samples and of radioiodinated TRH. 

A partially purified Bacillus thurlnglensis var. israelensls (Bti) 6-endotoxin was used to Immunize rabbits. The antisera obtained have an improved specificity towards the mosquito larvacidal activity of the toxin, as opposed to antiserum raised when the whole crystal was used as immunogen. Using a two step/indirect ELISA (enzyme linked immunosorbent assay) procedure developed in our laboratory, fourteen experimental formulations were tested, and the results were compared with bioassays. An average of 69.1 international units 20% c.v. was found to associate with each ug of toxin detected by the ELISA. Our data indicate that when toxin specific antisera are available, Immunoassays can be used to predict the biological activity of Bti samples with reasonable accuracy. 

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