title: Enhancement of tumor uptakes by stabilized Fab homo-oligomers of a chimeric monoclonal antibody against carcinoembryonic antigen.
abstract: We investigated the effect of stabilized Fab oligomerization by disuccinimidyl suberate on tumor uptake in a pancreatic carcinoma xenograft model in nude mice. Recombinant mouse/human chimeric Fab of the anti-carcinoembryonic antigen (CEA) monoclonal antibody A10, which was previously shown to react specifically with gastrointestinal cancers was used in this study. Fab homo-oligomers (dimers and trimers) chemically linked with ethylene bonds (C-C oligomers) were produced by linkage of chimeric Fab. Oligomers with C-C bonds had similar immunoreactivity against human CEA to parental Fab monomer. In biodistribution studies in animals bearing pancreatic carcinoma xenografts, at 12 and 24 h after infusion, C-C oligomers showed significantly greater uptakes in tumors than Fab or F(ab')2 but lower than IgG. However, oligomers with C-C bonds maintained higher tumor to normal tissue specificity ratios than IgG 24 h post-infusion. In conclusion, tumor uptake was enhanced by Fab oligomerization with C-C bonds, compared to Fab or F(ab')2, perhaps due to the larger molecular size. It was also shown that C-C Fab oligomers could have a potency to deliver high-dose radionuclides with reduced radio-uptakes in normal tissues for the radioimmunotherapy of gastrointestinal carcinomas.
authors.affiliation: First Department of Surgery, Kobe University School of Medicine, Chuo-ku, Kobe 650-0017, Japan.
authors.forename: T
authors.initials: T
authors.lastname: Kamigaki
authors.forename: T
authors.initials: T
authors.lastname: Ajiki
authors.forename: M
authors.initials: M
authors.lastname: Yamamoto
authors.forename: Y
authors.initials: Y
authors.lastname: Kuroda
mesh_terms: D000818:Animals; D000911:Antibodies, Monoclonal / Q000493:pharmacokinetics*; D001345:Autoradiography; D002272:Carcinoembryonic Antigen / Q000276:immunology*; D005260:Female; D006801:Humans; D007140:Immunoglobulin Fab Fragments / Q000378:metabolism*; D051379:Mice; D008807:Mice, Inbred BALB C; D008819:Mice, Nude; D009368:Neoplasm Transplantation; D010190:Pancreatic Neoplasms / Q000378:metabolism*; D011993:Recombinant Fusion Proteins / Q000493:pharmacokinetics*; D014018:Tissue Distribution; D014183:Transplantation, Heterologous
chemical_list: D000911:Antibodies, Monoclonal; D002272:Carcinoembryonic Antigen; D007140:Immunoglobulin Fab Fragments; D011993:Recombinant Fusion Proteins