Preparation, characterization, and biological evaluation of a streptavidin-chimeric t84.66 conjugate for antibody pretargeting.
In order to develop a new system for the antibody pretargeting of carcinoembryonic antigen (CEA)-positive cancers, a streptavidin (SA) conjugate of the monoclonal antibody (mAb) chimeric, T84.66, was synthesized and characterized. Antibody disulfide bonds were reduced with 1,4-dithiothreitol, and the resulting thiols were reacted with succinimidyl 4-(N-maleimidomethyl)cyclohexane-1-carboxylate-derivatized streptavidin (SMCC-SA). The desired SA-cT84.66 conjugate was purified by iminobiotin affinity chromatography and size-exclusion high-performance liquid chromatography (HPLC). The molecular weight of the SA-cT84.66 conjugate (210 kDa) and immounoreactivity (100%) were confirmed by size-exclusion HPLC, and the conjugate bound three equivalents of (111)In-DOTA-biotin. SA-cT84.66-pretargeted (111)In-DOTA-biotin was evaluated in nude mice bearing LS174T human colon carcinoma xenografts. Tumor uptake of (111)In-DOTA-biotin peaked at 3.32% injected dose per gram after 15 minutes. Clearance from blood and normal organs was extremely rapid, and tumor-to-blood ratios were >20:1 after 24 hours. The specific tumor targeting and rapid whole-body clearance of SA-cT84.66-pretargeted (111)In-DOTA-biotin indicated that this system is promising for the imaging and therapy of CEA-positive cancers.
Jia
Fang
F
Department of Veterinary Medicine and Surgery, College of Veterinary Medicine and Surgery, University of Missouri-Columbia, Columbia, MO 65211, USA.
Shelton
Tiffani D
TD
Lewis
Michael R
MR
D000818:Animals; D001710:Biotin / Q000031:analogs & derivatives / Q000737:chemistry; D002272:Carcinoembryonic Antigen / Q000276:immunology*; D045744:Cell Line, Tumor; D002851:Chromatography, High Pressure Liquid; D003110:Colonic Neoplasms / Q000378:metabolism* / Q000473:pathology / Q000532:radiotherapy; D006801:Humans; D000922:Immunotoxins / Q000737:chemistry* / Q000276:immunology / Q000493:pharmacokinetics*; D007205:Indium Radioisotopes / Q000737:chemistry / Q000493:pharmacokinetics; D008301:Maleimides / Q000737:chemistry; D051379:Mice; D008819:Mice, Nude; D015394:Molecular Structure; D009942:Organometallic Compounds / Q000737:chemistry; D016499:Radioimmunotherapy / Q000379:methods; D019809:Streptavidin / Q000737:chemistry; D014018:Tissue Distribution; D023041:Xenograft Model Antitumor Assays
D002272:Carcinoembryonic Antigen; C405616:DOTA-biotin; D000922:Immunotoxins; D007205:Indium Radioisotopes; D008301:Maleimides; D009942:Organometallic Compounds; D001710:Biotin; D019809:Streptavidin