Abstract
Clinical studies with the human anti-idiotypic antibody 105AD7 have clearly shown that 791Tgp72 is a good target antigen for cell-mediated immunity. No antibody-related toxicity was observed in any of the 135 patients entered into phase I/II clinical trials of 105AD7, whereas both helper and cytotoxic T-cell responses were induced. The helper responses were exemplified by induction of interleukin-2 (IL-2), antigen-specific blastogenesis, and enhanced natural killer (NK) activity. Anti-tumor cytotoxicity was measured directly and was supported by activation of circulating CD8 cells. In this study, it is shown that a 100-μg injection of 105AD7 was more effective than the 200-μg dose. Enhanced IL-2 production was observed following 15/19 injections of 100 μg of 105AD7 whereas only 4/11 injections of 200μg of 105AD7 induced responses (p < 0.02). Similarly, time to progression was significantly (p < 0.05) slower (median 6 m) in patients injected with 100 μg than patients receiving the higher dose, suggesting that 100 μg or lower may be the optimal dose. The standard dose for hepatitis vaccination is 10 μg. In vitro blastogenesis assays on naive donors have shown that a dose of 105AD7, which is either too high or too low, fails to activate T cells. The optimal dose in vitro is 10 ng.
Get full access to this article
View all access options for this article.