Japanese
Titleスペーサ含有および非含有二官能性キレート剤を用いた111In標識モノクローナル抗体の比較研究 - (I) 標識法およびin vitroでの安定性の検討 -
Subtitle原著
Authors孫保福*, 久田欣一**
Authors(kana)
Organization*金沢大学医学部核医学科, **主任:教授
Journal核医学
Volume31
Number5
Page459-471
Year/Month1994/5
Article原著
Publisher日本核医学会
Abstract「要旨」ジエステルスペーサを含むキレート剤succinimido-EGS-DTPA(EGS-DTPA)および炭化水素スペーサを含むキレート剤1-[4-(10-maleimidopropyl)amidobenzyl] ethylenediamine-N, N, N', N'-tetraaceticacid(C10-Bz-EDTA)と, これらの対照としてスペーサを含まないキレート剤cyclic DTPA dianhydride(cDTPAA)およびisothiocyanatobenzyl-EDTA(SCN-Bz-EDTA)を用い, A7抗体をモデルとしてモノクローナル抗体との反応条件, 111In標識, 免疫活性, in vitro安定性を検討した. EGS-DTPAと抗体をモル比10:1で反応させた場合, 抗体と結合した放射能標識率(標識率)は90%であり, cDTPAAと抗体をモル比2:1で反応させた場合の標識率は95.5%であった. また, SCN-Bz-EDTA, C10-Bz-EDTAをともにモル比1:1で抗体と結合反応させた場合, 標識率はおのおの70%, 80%であった. EGS-DTPAとcDTPAA結合抗体は, ともに血清中で放射能のトランスフェリンへの移行が認められ, さらにEGS-DTPA結合抗体ではIn-DTPAの形で抗体から放射能の解離が認められた. 一方, SCN-Bz-EDTAとC10-Bz-EDTA結合抗体は血清中で非常に安定であり, 168時間までは, ほとんどの放射能はIgGに相当する分子量分画に溶出された. 以上, C10-Bz-EDTAを用いて他のキレートと同様に, 免疫活性を保ちかつ十分高い比放射能の標識抗体を得ることが可能であった. また, C10-Bz-EDTA結合抗体の血中での安定性から, 本キレート剤のEGS-DTPAに対する優位性が示唆された.
Practice臨床医学：一般
KeywordsMonoclonal antibody, Bifunctional chelate, Diester spacer, Hydrocarbon spacer, Transchelation.
English
TitleComparative Studies of 111In-Labeled Monoclonal Antibody Using Spacer-Containing and Non-spacer Bifunctional Chelates : (I) Conjugation, Labeling Immunoreactivity and In Vitro Stability
SubtitleOriginal Articles
AuthorsBaofu SUN
Authors(kana)
OrganizationDepartment of Nuclear Medicine, Kanazawa University School of Medicine
JournalThe Japanese Journal of nuclear medicine
Volume31
Number5
Page459-471
Year/Month1994/5
ArticleOriginal article
PublisherTHE JAPANESE SOCIETY OF NUCLEAR MEDICINE
Abstract[Summary] Bifunctional chelates containing chemical spacer, succinimido-EGS-DTPA (EGS-DTPA, diester spacer) and 1-[4-(10-maleimidopropyl) amidobenzyl] ethylenediamine-N, N, N',N'-tetraacetic acid (C10-Bz-EDTA, hydrocarbon spacer) were synthesized and compared in vitro with non-spacer chelates, cyclic DTPA dianhydride (cDTPAA) and isothiocyanatobenzyl-EDTA (SCN-Bz-EDTA). The optimum condition for conjugation with chelates, labeling efficiency, immunoreactivity and stability in the serum were investigated with respect to four chelates. The labeling efficiency for EGS-DTPA-A7 and DTPA-A7 was 90% and over 95%, respectively, when reacted by the chelate to anti-body ratios of 10:1 for EGS-DTPA and 2:1 for cDTPAA. The labeling efficiency for SCN-Bz-EDTA and C10-Bz-EDTA was 70% and 80%, respectively, when both of the chelates were conjugated with the antibody in a 1:1 ratio. EGS-DTPA-A7 and DTPA-A7 were unstable when incubated in the human serum at 37℃ and showed the transchelation to the transferrin fraction of the 111In activity. Furthermore, the radioactivity from 111In-EGS-DTPA-A7 was also found to be associated with the In-DTPA fraction, indicating that the diester spacer was cleaved in the serum. SCN-Bz-EDTA-A7 and C10-Bz-EDTA-A7 were very stable: there was no evidence of transchelation or any activity was dissociated from the conjugated antibody when incubated in the human serum for 168 hrs. Using C10-Bz-EDTA, immunoconjugate with sufficient specific activity was obtained and high immunoreactivity was maintained. It was considerable that the C10-Bz-EDTA immunoconjugate would produce preferable biodistribution than EGS-DTPA immunoconjugate do.
PracticeClinical medicine
KeywordsMonoclonal antibody, Bifunctional chelate, Diester spacer, Hydrocarbon spacer, Transchelation.

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