Dose response of RIT in B-cell lymphoma models. Unlabeled anti-Id mAb was added to 131I-labeled anti-MHCII mAb (RIT) in the treatment of murine lymphomas. (A) Animals were inoculated with 105 BCL1 cells by intravenous injection and treated with 500 μg anti-Id mAb per animal given 2 hours before RIT on day 10. (B) For the A31 model, animals were inoculated with 106 tumor cells and treated with 100 μg anti-Id mAb by intravenous injection 8 days later. This experiment is representative of 1 of 3 similar experiments. In both models, 9.25 MBq 131I anti-MHCII and 18.5 MBq 131I anti-MHCII provided very similar levels of protection. In contrast, with the addition of anti-Id mAb, a clear dose response was seen in both BCL1 and A31 models with 18.5 MBq 131I anti-MHCII in conjunction with anti-Id providing highly significant improvements in survival over the 9.25 MBq RIT dose and untreated controls (P < .01).
