Development and performance of an enzyme immunoassay to detect creatine kinase isoenzyme MB activity using anti-mitochondrial creatine kinase monoclonal antibodies

• Published in: Scandinavian journal of clinical and laboratory investigation 2009, Vol.69 (6), p.687-695
• Main Authors: Hoshino, Tadashi, Sakai, Yasuhiro, Yamashita, Kazuaki, Shirahase, Yasushi, Sakaguchi, Kouji, Asaeda, Ayumi, Kishi, Kouji, Schlattner, Uwe, Wallimann, Theo, Yanai, Mitsuru, Kumasaka, Kazunari
• Format: Article
• Language: English
• Subjects: Antibodies, Monoclonal - pharmacology; Antibody Specificity - drug effects; Binding Sites, Antibody; Biological markers; Creatine Kinase, BB Form - antagonists & inhibitors; Creatine Kinase, BB Form - blood; Creatine Kinase, MB Form - antagonists & inhibitors; Creatine Kinase, MB Form - blood; Creatine Kinase, Mitochondrial Form - antagonists & inhibitors; Creatine Kinase, Mitochondrial Form - blood; Creatine Kinase, Mitochondrial Form - immunology; diagnostics reagent kits; Electrophoresis; Health; Humans; Immunoenzyme Techniques - methods; Immunoenzyme Techniques - standards; Isoenzymes - antagonists & inhibitors; Isoenzymes - blood; Macro-creatine kinase; MB creatine kinase; Membranes, Artificial; Mitochondrial creatine kinase; Molecular Weight; myocardial infarction; Reference Values
• ISSN: 0036-5513; 1502-7686
• DOI: 10.3109/00365510902981171

Abstract Objective: The MB fraction of creatine kinase (CK-MB) has long been used as a cardiac marker. It is known that the CK-MB immunoinhibition method lacks selectivity and accuracy, because the appearance of macro CK type 2, corresponding to mitochondrial creatine kinase (MtCK) in some patient serum may render CK-MB activity measured by conventional method abnormally high. Thus, to improve the specificity and accuracy of the CK-MB assay, we developed two types of monoclonal anti-MtCK antibodies against sarcomeric MtCK and ubiquitous MtCK, and present herein the performance of a new method using these antibodies. Material and methods: The performance of our test for detecting CK-MB activity was compared with other methods, and the range of CK-MB activities in normal human serum was investigated. Results: The two types of monoclonal antibodies developed by us were isoenzyme-specific to sMtCK or uMtCK. The correlation coefficients of our method and conventional method to electrophoresis were 0.973 and 0.873, respectively. The mean CK-MB activity in normal human serum by our method and the conventional method was 2.4 and 11.7 U/L, respectively. Thus, our data indicated that about 80% of CK-MB activity, determined using the conventional method, seems to correspond to the MtCK activity. Conclusion: Our method is novel in offering higher accuracy of measuring true CK-MB contents in human serum as compared to the conventional method. The possibility of accurately estimating CK-MB activity by our method which can inhibit MtCKs in healthy person and patient serum is likely to bring a break-through in clinical diagnostics.