Technetium-99m labeling of antibodies to cardiac myosin Fab and to human fibrinogen.
We have developed a method of labeling biologically active labile macromolecules, such as human fibrinogen (HF) and anticardiac-myosin Fab (AM-Fab), with Tc-99m at neutral pH. This method uses dithionite reduction of pertechnetate and subsequent labeling, to test the method with acid-labile macromolecules. Complexes of diethylene triamine pentaacetic acid with macromolecules such as human fibrinogen (D-HF) and anticardiac-myosin Fab (D-AM-Fab) were labeled and utilized in in vitro and in vivo studies. In biodistribution studies, the Tc-99m D-HF had a two-component blood clearance (half-times 1 hr and 15 hr) and was 80--88% coagulable. The Tc-99m AM-Fab retained its immunoreactivity as tested by affinity chromatography; also during in vivo localization in experimental myocardial infarction. This labeling technique provides an easy and efficient approach to the Tc-99m labeling of other biologically active and acid-labile macromolecules.
D000818:Animals; D000906:Antibodies / Q000378:metabolism; D004285:Dogs; D005340:Fibrinogen / Q000276:immunology*; D006801:Humans; D007140:Immunoglobulin Fab Fragments / Q000378:metabolism; D007553:Isotope Labeling / Q000379:methods; D051379:Mice; D009203:Myocardial Infarction / Q000000981:diagnostic imaging; D009206:Myocardium / Q000276:immunology*; D009218:Myosins / Q000276:immunology*; D011877:Radionuclide Imaging; D013667:Technetium; D014018:Tissue Distribution
D000906:Antibodies; D007140:Immunoglobulin Fab Fragments; D013667:Technetium; D005340:Fibrinogen; D009218:Myosins