COMPARISON OF 4 STRATEGIES FOR TUMOR VACCINATION IN THE B16-F10 MELANOMA MODEL

We have compared four cell-based tumour vaccine strategies in preventi on experiments using the B16-F10 melanoma model. Two of these are thou ght to favour the direct antigen presentation pathway (B16-F10 express ing B7.1 and hybrids made between B16-F10 cells and macrophages) and t he other two strategies are thought to act by an indirect pathway of p resentation (allogeneic tumour cells and autologous tumour cells combi ned with a powerful adjuvant (Provax-IDEC Pharmaceuticals)). Only the two latter vaccines promoted antitumour activity, whereas the vaccines consisting of B7.1-expressing tumour cells or the hybrid vaccine fail ed to provide any antitumour activity. Recently human trials have comm enced using transfection of the B7.1 molecule, as well as employing th e hybrid technology to make tumour-B cell hybrids or tumour and dendri tic cell hybrids. Our results suggest that these approaches could be d isappointing in the clinics if not optimised.