Specific versus nonspecific immunization.

To differentiate between target-antigen–dependent and –independent immunization effects induced by the bsAb BiLu, mice were immunized as outlined in Figure 4 with bsAb and irradiated A20-EpCAM cells (▪), or with bsAb and nontransfected A20 wild-type cells (■). Only the use of A20-EpCAM cells resulted in full tumor protection. Control mice (+) that received irradiated A20 wild-type cells without bsAb revealed no protection. Each group comprised 6 mice.