Application of 99mTc labeled chimeric Fab fragments of monoclonal antibody A7 for immunoscintigraphy of pancreatic carcinoma.
BACKGROUND
One of the reasons for the poor prognosis of pancreatic carcinoma is the difficulty of obtaining an early diagnosis of pancreatic carcinoma. One possibility is the application of radioimmunoscintigraphy using radiolabeled monoclonal antibodies (Mabs).


METHODS
We labeled chimeric (human/mouse) Fab fragments of Mab A7 (chA7Fab) with (99m)Tc and examined the distribution of (99m)Tc-labeled chA7Fab in nude mice bearing human pancreatic carcinoma.


RESULTS
The tumor accumulation of (99m)Tc-labeled chA7Fab was larger than that of (99m)Tc-labeled A7 from 2 to 6 hr after injection. (99m)Tc-labeled chA7Fab disappeared from blood more rapidly than (99m)Tc-labeled A7. For all resected normal tissues except kidney, the accumulation of (99m)Tc-labeled chA7Fab was low and similar to that of (99m)Tc-labeled A7.


CONCLUSIONS
Because the half-life of (99m)Tc is short (6 hr), chA7Fab, which accumulates rapidly in tumors, may be a better carrier of (99m)Tc than intact Mab A7.
Department of Surgery, Kyoto Prefectural University of Medicine, Kyoto, Japan. otsuji@koto.kpu-m.ac.jp
Eigo
E
Otsuji
Hiroomi
H
Matsumura
Kazuma
K
Okamoto
Atsushi
A
Toma
Yoshiaki
Y
Kuriu
Daisuke
D
Ichikawa
Akeo
A
Hagiwara
Hisakazu
H
Yamagishi
D000818:Animals; D000911:Antibodies, Monoclonal / Q000493:pharmacokinetics; D045744:Cell Line, Tumor; D006801:Humans; D007140:Immunoglobulin Fab Fragments / Q000276:immunology*; D051379:Mice; D008819:Mice, Nude; D010190:Pancreatic Neoplasms / Q000000981:diagnostic imaging* / Q000378:metabolism; D016719:Radioimmunodetection; D013667:Technetium / Q000493:pharmacokinetics; D014018:Tissue Distribution
D000911:Antibodies, Monoclonal; D007140:Immunoglobulin Fab Fragments; D013667:Technetium