Evaluation of an anti-carcinoembryonic monoclonal antibody suitable for immunoscintigraphy

Evaluation of an anti-carcinoembryonic monoclonal antibody suitable for immunoscintigraphy

Author Moraes, D. W. Google Scholar
Lima, Eduardo Nobrega Pereira Autor UNIFESP Google Scholar
Prado, I. B. Google Scholar
Carneiro, Celia Regina Whitaker Autor UNIFESP Google Scholar
Institution Universidade Federal de São Paulo (UNIFESP)
Inst Ludwig Pesquisa Canc
Fundacao Antonio Prudente
Universidade de São Paulo (USP)
Abstract An anti-carcinoembryonic antigen (CEA) monoclonal antibody (mAb 6D1.1) was evaluated in vitro and in vivo to determine its suitability as a tracer for immunoscintigraphy of colorectal carcinomas. Determination of mAb affinity for CEA showed a constant of association of 0.63 +/- 0.11 x 10(9) M-1. Binding of technetium-99m (Tc-99m)-6D1.1, labeled by a direct method, to human cultured lineages was highly specific. Binding to only CEA-positive LS-174T cells resulted in a saturable curve inhibited by pre-incubation with unlabeled mAb. No binding at all was observed for the human lineages MeWo (melanoma) or ZR75-30 (breast carcinoma), neither of them expressing CEA cells. Intravenous injection of Tc-99m-6D1.1 into nude mice xenografted with human LS-174T tumors resulted in planar images of excellent quality. Localization of an irrelevant mAb labeled with either Tc-99m or iodine-125 was never observed in tumor masses. Biodistribution studies on excised tumoral tissue showed retention of 28.48% of the injected dose per gram of LS-174T tumor. The tumor-to-blood ratio was 3.46. The same analysis performed on the other three human xenografted tumors studied demonstrated that only the CEA-producing HT-29 (colorectal adenocarcinoma) retained Tc-99m-6D1.1 while the other two (ZR75-30 and MeWo) did not. These data demonstrate that this mAb is an adequate tool for targeting CEA-expressing tumors in experimental models.
Keywords monoclonal antibody
carcinoembryonic antigen
colorectal carcinoma
immunoscintigraphy
technetium-99m
Language English
Date 1999-08-01
Published in Brazilian Journal Of Medical And Biological Research. Sao Paulo: Assoc Bras Divulg Cientifica, v. 32, n. 8, p. 967-974, 1999.
ISSN 0100-879X (Sherpa/Romeo, impact factor)
Publisher Assoc Bras Divulg Cientifica
Extent 967-974
Origin http://dx.doi.org/10.1590/S0100-879X1999000800006
Access rights Open access Open Access
Type Article
Web of Science ID WOS:000082138100006
SciELO ID S0100-879X1999000800006 (statistics in SciELO)
URI http://repositorio.unifesp.br/11600/43125

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