ABSTRACT
The cardiac isoform of troponin I is a reliable biomarker of damaged cardiomyocytes that accompanies such severe cardiovascular diseases as myocardial infarction. Monoclonal antibody 19C7 recognizes troponin I in the bloodstream with high affinity and specificity. Recombinant antibodies can be used to improve detection systems based on monoclonal antibodies produced with hybridoma technology. In the present study, we compare the properties of monoclonal antibody 19C7 and its recombinant fragments. It is shown that the recombinant antibody fragments demonstrate similar affinity values as monoclonal antibodies and can be applied for troponin I detection.
Subject(s)
Antibodies, Monoclonal/chemistry , Immunoassay/methods , Immunoglobulin Fab Fragments/immunology , Recombinant Proteins/immunology , Troponin I/blood , Troponin I/immunology , Acute Disease , Antibodies, Monoclonal/immunology , Biotinylation , Cell Line , Humans , Immunochemistry , Immunoglobulin Fab Fragments/chemistry , Kinetics , Myocardial Infarction/blood , Myocardium/metabolism , Single-Chain Antibodies/chemistry , Single-Chain Antibodies/immunologyABSTRACT
OBJECTIVES: Pregnancy Associated Plasma Protein A (PAPP-A)-derived N- and C-terminal fragments of IGF-binding protein-4 (NT- and CT-IGFBP-4) released from vulnerable atherosclerotic plaques are proposed to be used for cardiovascular risk assessment. DESIGN AND METHODS: NT- and CT-IGFBP-4 were measured by novel immunoassays in EDTA-plasma of 180 patients admitted to the emergency department with symptoms of myocardial ischemia but without ST-segment elevation. Six-month incidence of major adverse cardiac events (MACE), including myocardial infarction, cardiac death, percutaneous coronary interventions, and coronary artery bypass grafting was recorded. RESULTS: Sixteen patients met the endpoint. NT- and CT-IGFBP-4 were strong predictors of MACE: area under ROC curve (AUC) 0.856 and 0.809, respectively. NT-IGFBP-4 concentrations≥214µg/L and CT-IGFBP-4 concentrations≥124µg/L were associated with increased risk of future MACE: adjusted hazard ratio 13.79 and 7.93, respectively. CONCLUSIONS: IGFBP-4 fragments can be utilized as biomarkers for MACE prediction in patients with suspected myocardial ischemia.
Subject(s)
Insulin-Like Growth Factor Binding Protein 4/blood , Myocardial Ischemia/diagnosis , Peptide Fragments/blood , Aged , Aged, 80 and over , Amino Acid Sequence , Animals , Area Under Curve , Biomarkers/blood , Coronary Artery Bypass , Cross Reactions , Female , HEK293 Cells , Humans , Immunoassay , Male , Mice , Mice, Inbred BALB C , Middle Aged , Molecular Sequence Data , Myocardial Ischemia/pathology , Plaque, Atherosclerotic/metabolism , Pregnancy-Associated Plasma Protein-A/analysis , Proportional Hazards Models , Prospective Studies , Proteolysis , ROC Curve , Risk Assessment , Risk Factors , Sensitivity and Specificity , Time FactorsABSTRACT
Highly specific interaction with foreign molecules is a unique feature of antibodies. Since 1975, when Keller and Milstein proposed the method of hybridoma technology and prepared mouse monoclonal antibodies, many antibodies specific to various antigens have been obtained. Recent development of methods for preparation of recombinant DNA libraries and in silico bioinformatics approaches for protein structure analysis makes possible antibody preparation using gene engineering approaches. The development of gene engineering methods allowed creating recombinant antibodies and improving characteristics of existing antibodies; this significantly extends the applicability of antibodies. By modifying biochemical and immunochemical properties of antibodies by changing their amino acid sequences it is possible to create antibodies with properties optimal for certain tasks. For example, application of recombinant technologies resulted in antibody preparation of high affinity significantly exceeding the initial affinity of natural antibodies. In this review we summarize information about the structure, modes of preparation, and application of recombinant antibodies and their fragments and also consider the main approaches used to increase antibody affinity.