The Use of a Poultry-Specific Murine Monoclonal Antibody Directed to the Insoluble Muscle Protein Desmin in Meat Speciation

Abstract

Monoclonal antibodies were produced using chicken smooth muscle desmin as the immunogen and one antibody, 4B4/B2, was found to be reactive with desmin from chicken, turkey, pheasant and duck but not from lamb, beef and pork. This antibody reacts with poultry desmin from both smooth muscle and skeletal muscle, allowing its use for the detection of poultry meat in other meats. In addition to reacting with intact forms of this cytoskeletal protein (apparent subunit molecular size 54 kDa), 4B4/B2 also reacts with degradation products of desmin (30–40 kDa), thus enhancing its use for speciation purposes. When the antibody is used in an indirect ELISA involving antigen-coated plates, it can detect <0·04 μg ml−1 poultry desmin. As desmin is one of the most insoluble proteins in cells, it is an ideal marker for speciation. Desmin-enriched samples can be produced from chicken meat and chicken/red meat mixtures by differential extraction, culminating with the solubilisation of desmin in 8M urea. These extracts can be analysed using the ELISA system, routinely detecting chicken at the 100 g kg−1 mixed meats level. Alternatively, Western blots of the samples, resolved by 100 g kg−1 SDS PAGE, can be probed with 4B4/B2 allow-ing detection at the 20 g kg−1 mixed meats level. This monoclonal antibody rep-resents a standard reagent of unlimited supply which can, for the first time, detect a defined insoluble protein in poultry speciation assays. Preliminary applications indicate that it is superior to other reagents and demonstrate that desmin has the potential to be a valuable marker for speciation.