Radiolabeling of monoclonal anti-CD105 with (177)Lu for potential use in radioimmunotherapy.
In this study, we carried out a radioimmunoconjugation using (177)Lu with anti-CD105 (endoglin) monoclonal antibody for an angiogenesis targeting. CD105 has been shown to be a more useful marker to identify proliferating endothelium involved in tumor angiogenesis than panendothelial markers. We optimized the labeling of the anti-CD105 monoclonal antibody with (177)Lu by using cysteine derivative isothiocyanatobenzyl-DTPA (DTPA-NCS) as BFCA. Under the optimal conditions, labeling yield was greater than 99%. Immunoactivity of the radioimmunoconjugate was investigated using combinations of radioanalytical and bioanalytical techniques (ITLC-SG, Cyclone phosphorimager, SDS-PAGE and ELISA). For the biological evaluations we carried out a cell binding assay and a biodistribution study using mice bearing Calu6 lung cancer cell xenografts. The tumor-to-blood ratio was 11.16:1 24h post-injection. In conclusion, the anti-CD105 monoclonal antibody for an angiogenesis targeting was effectively radioconjugated with (177)Lu. And the biodistribution study showed a high specificity for accumulating in tumor tissues. This radioimmunoconjugate is applicable to detect angiogenesis sites in various diseases and to treat tumors.
Lee
So-Young
SY
Radioisotope Research Division, Basic Science and Technology Department, Korea Atomic Energy Research Institute (KAERI), Yuseong, Daejeon 305-353, Republic of Korea.
Hong
Young-Don
YD
Felipe
Penelope M
PM
Pyun
Mi-Sun
MS
Choi
Sun-Ju
SJ