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United States Department of Agriculture

Agricultural Research Service

Title: Development of Antibodies Against the Fluoroquinolone Sarafloxacin and Molecular Modeling Studies of Cross-Reactive Compounds

Authors
item Holtzapple, Carol
item Buckley, Sandra
item Stanker, Larry

Submitted to: Food and Agricultural Immunology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: September 20, 1996
Publication Date: N/A

Interpretive Summary: Sarafloxacin is an antibiotic drug used to prevent early death in poultry associated with E. coli infection. A simple, rapid enzyme-linked immunosorbent assay (ELISA) was developed to detect residues of this drug in food products. No such simple method is presently in use. The ELISA that was developed is based upon a monoclonal antibody that is sensitive for sarafloxacin. Rapid immunochemical assays such as the one described here should help producers as well as government agencies to screen poultry products for the presence sarafloxacin residues.

Technical Abstract: Polyclonal antibodies were prepared against the fluoroquinolone sarafloxacin. Sarafloxacin was conjugated directly to cationized bovine serum albumin and ovalbumin. Balb/c mice were immunized with the sarafloxacin-BSA conjugate (cBSA-Saraflox) and sarafloxacin reactive sera (1-5) from these mice were obtained. Serum from mouse 1 (Ab1) exhibited the lowest IC50 for free sarafloxacin using an indirect competitive inhibition enzyme-linked immunosorbent assay (ci-ELISA). Other structurally related quinolones including difloxacin, enrofloxacin, norfloxacin, trovafloxacin, and nalidixic acid demonstrated cross- reactivity with the sarafloxacin antibodies as determined by ci-ELISA. In an effort to correlate antibody binding with three-dimensional properties of the cross-reactive compounds, all of the fluoroquinolones as well as nalidixic acid were modeled and global energy minima were determined using molecular mechanical and quantum mechanical methods. The results demonstrate that the three-dimensional models can yield information that explains observed cross-reactivity data. These models are particularly helpful when the chemical structure of an analog varies greatly from the immunogen, yet the IC50 value for the compound is not vastly different. Furthermore, conformational and electronic data from this study can be used to predict whether other fluoroquinolones will exhibit good cross- reactivity in this ELISA.

Last Modified: 10/24/2014