Selective cytotoxicity of 125I-labeled monoclonal antibody T101 in human
malignant T cell lines
E Boven, T Lindmo, JB Mitchell and PA Bunn
The radiolabeled anti-T cell antibody T101 can be used for specific tumor
localization, but unlabeled T101 produces limited cytotoxicity in patients.
We thus studied the in vitro cytotoxic effects of T101 labeled with 125I, a
radionuclide known for its short-range, high- linear-energy electrons. We
showed that 125I-T101 could be readily prepared at high specific activity
with high immunoreactivity. Human malignant T cell lines HUT 102, MOLT-4,
and HUT 78 were found to differ in the number of T65 determinants (the
antigen recognized by T101) and the sensitivity to external x-ray
radiation, which were of significance for the cytotoxicity of 125I-T101 in
vitro. The cytotoxic effects of 125I-T101 were also found to be dose
dependent and increased with exposure time under frozen conditions. As
controls, unlabeled T101 had no cytotoxic effect, while free Na 125I or the
125I-labeled irrelevant antibody 9.2.27 exerted minor cytotoxicity. In HUT
102 and MOLT-4, more than 3 logs' cell killing was achieved within four
weeks. Because considerable cytotoxicity was demonstrated in vitro by
125I-T101 on T65- positive malignant cells, and because low-dose 111In-T101
can be used successfully for tumor localization, future trials using
125I-T101 at high specific radioactivity may improve therapeutic results in
patients with T65-positive malignancies.
Volume 67,
Issue 2,
pp. 429-435,
02/01/1986
Copyright © 1986 by The American Society of Hematology
