Evaluation of two new bifunctional chelates for radiolabeling a parathyroid-specific monoclonal antibody with In-111.
BB5-G1, a monoclonal antibody specific for human parathyroid cell membrane antigen was conjugated with two new ligands, BrMe2HBED and Br phi HBED and radiolabeled with 111In. We have compared the biodistribution of 111In-labeled BB5 using the new ligands to conventionally labeled (125I-labeled and 111In-DTPA-labeled) BB5 in a nude mouse model. Both 111In-BrMe2HBED-BB5 and 111In-Br phi HBED-BB5 attained high parathyroid-to-blood and parathyroid-to-muscle ratios by 72-96 h. 111In-Br phi HBED-BB5 showed lower %ID/g than 111In-BrMe2HBED-BB5 in the clearance organs, the liver and kidney; renal activity had cleared significantly by 120 h. This work suggests that 111In-Br phi HBED-BB5 offers improved in vitro behavior and may be useful as a radiopharmaceutical for localizing parathyroid tissue.
Edward Mallinckrodt Institute of Radiology, Washington University School of Medicine, St Louis, MO 63110.
S W
SW
Schwarz
C J
CJ
Mathias
J Y
JY
Sun
W G
WG
Dilley
S A
SA
Wells
A E
AE
Martell
M J
MJ
Welch
D000818:Animals; D000911:Antibodies, Monoclonal; D002614:Chelating Agents; D004492:Edetic Acid / Q000031:analogs & derivatives* / Q000032:analysis* / Q000737:chemistry; D005069:Evaluation Studies as Topic; D007150:Immunohistochemistry; D007205:Indium Radioisotopes; D007553:Isotope Labeling; D008024:Ligands; D051379:Mice; D008810:Mice, Inbred C57BL; D008819:Mice, Nude; D010280:Parathyroid Glands / Q000276:immunology*; D014018:Tissue Distribution
D000911:Antibodies, Monoclonal; D002614:Chelating Agents; D007205:Indium Radioisotopes; D008024:Ligands; C071350:N-(2-hydroxy-3,5-dimethylbenzyl)-N-(2-hydroxy-5-bromoacetamidobenzyl)ethylenediamine-N,N'-diacetic acid; C069116:N,N'-bis(2-hydoxybenzyl)-1-(4-bromoacetamidobenzyl)-1,2-ethylenediamine-N,N'-diacetic acid; D004492:Edetic Acid