Monoclonal antibody to an intracellular antigen images human melanoma transplants in nu/nu mice.
Mouse monoclonal antibody TA99 detects a 70-kDa pigmentation-associated glycoprotein in human melanoma cell lines. The antigen cannot be detected on the cell surface by sensitive rosetting techniques or absorption studies, nor can it be detected as a secreted product in culture fluids. Contrary to expectation, 125I-labeled TA99 specifically localized to pigmented human melanoma transplants in nu/nu mice; no localization to nonpigmented melanoma or control tumors was found. Tumor imaging was initially obscured by circulating 125I-labeled TA99 during the first 6 days after antibody injection. With clearance of 125I-labeled TA99 from the blood (half-life, 4-7 days), specific tumor images could be clearly defined by day 13. Due to the persistence of 125I-labeled TA99 at the tumor site (8.9% of the injected dose at 1 week and 4.6% at 8-10 weeks), images were obtainable for up to 10 weeks. At 8-10 weeks, the tumor/blood ratio was 10(4)-10(5), and the tumor/normal tissue ratio ranged from 10(2) to 10(5). In view of these findings, antibodies detecting intracellular antigens may have a role in tumor imaging and therapy.
Welt
S
S
Mattes
M J
MJ
Grando
R
R
Thomson
T M
TM
Leonard
R W
RW
Zanzonico
P B
PB
Bigler
R E
RE
Yeh
S
S
Oettgen
H F
HF
Old
L J
LJ
D000818:Animals; D000911:Antibodies, Monoclonal; D000936:Antigen-Antibody Complex; D000951:Antigens, Neoplasm / Q000032:analysis*; D002460:Cell Line; D006801:Humans; D007457:Iodine Radioisotopes; D008545:Melanoma / Q000000981:diagnostic imaging / Q000276:immunology* / Q000473:pathology; D051379:Mice; D008819:Mice, Nude; D009368:Neoplasm Transplantation; D011877:Radionuclide Imaging; D014183:Transplantation, Heterologous
D000911:Antibodies, Monoclonal; D000936:Antigen-Antibody Complex; D000951:Antigens, Neoplasm; D007457:Iodine Radioisotopes