Immunoreactivity of 111In and 131I fibrin-specific monoclonal antibody used for thrombus imaging.
Immunoreactivity of radiolabeled F(ab')2 fragment of anti-fibrin T2G1s monoclonal antibody was determined by affinity chromatography using fibrin-coated Sepharose. This preparation is useful for thrombus detection in vivo by gamma camera imaging, provided a high percentage of immunoreactivity is retained after labeling. For 111In labeling, DTPA/F(ab')2 molar ratios were varied from 1000 to 6600/1, with little effect on immunoreactivity. Immunoreactivity of the F(ab')2 fragment, labeled with imaging doses of 131I and 111In, remained high and ranged from 81% to 89%. Equilibrium binding analysis determined the affinity constants of 111In- or 125I-labeled T2G1s and its F(ab')2 and Fab fragments, to be equivalent (Kd approximately 3 X 10(-8) M). This suggests that only one binding domain of T2G1s binds to fibrin even though there are two antigenic sites/mol of fibrin.
Rosebrough
S F
SF
Department of Radiology, SUNY Health Science Center, Syracuse 13210.
McAfee
J G
JG
Grossman
Z D
ZD
Schemancik
L A
LA
D000911:Antibodies, Monoclonal / Q000276:immunology*; D000915:Antibody Affinity; D002846:Chromatography, Affinity; D005337:Fibrin / Q000276:immunology*; D006801:Humans; D007140:Immunoglobulin Fab Fragments / Q000276:immunology; D007205:Indium Radioisotopes; D007457:Iodine Radioisotopes; D011877:Radionuclide Imaging; D013927:Thrombosis / Q000000981:diagnostic imaging
D000911:Antibodies, Monoclonal; D007140:Immunoglobulin Fab Fragments; D007205:Indium Radioisotopes; D007457:Iodine Radioisotopes; D005337:Fibrin