THE USE OF A POULTRY-SPECIFIC MURINE MONOCLONAL-ANTIBODY DIRECTED TO THE INSOLUBLE MUSCLE PROTEIN DESMIN IN MEAT SPECIATION

Monoclonal antibodies were produced using chicken smooth muscle desmin as the immunogen and one antibody, 4B4/B2, was found to be reactive w ith desmin from chicken, turkey, pheasant and duck but not from lamb, beef and pork. This antibody reacts with poultry desmin from both smoo th muscle and skeletal muscle, allowing its use for the detection of p oultry 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), t hus enhancing its use for speciation purposes. When the antibody is us ed in an indirect ELISA involving antigen-coated plates, it can detect < 0.04 mu g ml(-1) poultry desmin. As desmin is one of the most insol uble proteins in cells, it is an ideal marker for speciation. Desmin-e nriched samples can be produced from chicken meat and chicken/red meat mixtures by differential extraction, culminating with the solubilisat ion of desmin in 8 M urea. These extracts can be analysed using the EL ISA system, routinely detecting chicken at the 100 g kg(-1) mixed meat s level. Alternatively, Western blots of the samples, resolved by 100 g kg(-1) SDS PAGE, can be probed with 4B4/B2 allowing detection at the 20 g kg(-1) mixed meats level. This monoclonal antibody represents a standard reagent of unlimited supply which can, for the first time, de tect a defined insoluble protein in poultry speciation assays. Prelimi nary applications indicate that it is superior to other reagents and d emonstrate that desmin has the potential to be a valuable marker for s peciation.