The Effect of Iodine-131-Rituximab on B Cell Lymphoma In Vitro and In Vivo.

The purpose of this study was to investigate the cell specific cytotoxic effect of Iodine-131 Rituximab on CD20-positive B cell lymphoma in vitro and on Raji cell tumors grown in vivo. Rituximab was labeled with Iodine -131 by the iodogen method. Cultured Raji cells or the nude mice bearing Raji tumors were treated with various concentrations of Iodine-131-Rituximab or Iodine-131 alone or Rituximab alone. The results showed that

1. The lethal effect was found on Raji cells treated with Iodine-131-Rituximab in a dose-dependent manner;

2. The proliferation rate of Raji cells was significantly lower in cells treated with Iodine-131-Rituximab, as compared to the cells treated with Iodine-131or Rituximab alone (P<0.05);

3. Tumor inhibition was found to be greatest in the mice treated with Iodine-131-Rituximab through intratumor injection, as compared with Iodine-131-Rituximab i.p. injection or Rituximab alone (p<0.05).

We conclude that Iodine-131-Rituximab specifically inhibits the growth of Raji tumor cells in vitro and in vivo. Iodine-131-Rituximab is a promising agent for radioimmunotherapy that targets CD20-positive B cell lymphoma.