抄録
Radiolabeled antibody has attractive features as a therapeutic agent or diagnostic reagent. However, it is difficult for radiolabeled antibody to enter the central nervous system (CNS). The purpose of this study was to develop a method of delivering radiolabeled single-chain Fv (scFv) antibody into the CNS with the transactivator of transcription (TAT), one of the protein transduction domains. Oligonucleotide encoding TAT was linked to the 5′-terminal of the scFv gene. The construct was subcloned into the pET-23b vector, and the recombinant protein was expressed as an inclusion body in Escherichia coli. After solubilization and purification, the recombinant protein was oxidatively labeled with 125I, and the radiolabeled recombinant protein was injected intraperitoneally into mice. Six hours later the brains were collected and homogenized, and the protein fractions were prepared by acetone precipitation. The radioactivity in the cerebrum was about 1.6-fold higher in mice administered TAT-scFv than in those administered scFv alone. The radiolabeled TAT-scFv antibody was delivered into the cerebrum more efficiently than radiolabeled scFv antibody without TAT, suggesting that TAT peptide could be a candidate tool for delivering radiolabeled scFv antibody into the CNS.
