SYNTHETIC PEPTIDE IMMUNOGENS FOR THE DEVELOPMENT OF A CARDIAC MYOSIN LIGHT CHAIN-1 SPECIFIC RADIOIMMUNOASSAY

To determine if the presence of cardiac light chains in blood could be used to detect acute myocardial infarction, we developed a specific l ight chain immunoassay. A synthetic peptide sequence specific for huma n cardiac ventricular myosin light chain 1 (VLC1) was synthesized and designated P348. This peptide coupled to keyhole limpet hemocyanin was used as an immunogen to obtain murine monoclonal antibodies specific for VLC1. Five monoclonal antibodies were obtained. One of these desig nated Mab-8E3 reacted equally well with both the synthetic peptide and VLC1. Although the 8E3 antibody is specific for VLC1, the use of HPLC purification of skeletal muscle myosin light chain 1 demonstrated tha t VLC1 is present in human skeletal muscle. The clinical utility of th e assay was tested in 18 patients with creatine kinase (CK) and ECG do cumented acute myocardial infarction. VLC1 was below the limit of dete ction (<1 ng/ml) in sera obtained from healthy volunteers and patients without myocardial infarction or chest pain. In contrast VLC1 was ele vated in the serum of all 18 patients with acute myocardial infarction . Combining the two test results at the time of admission resulted in 83% of patients having detectable serum levels of one or both markers.