In the B16.F10 mouse melanoma model, in vivo depletion of murine B cells with an anti-CD20 monoclonal antibody attenuated the antigen-specific responses of CD4+ and CD8+ T cells.19 Antibodies coupled to tumour proteins have been shown to induce CD8+ T cell activation via cross presentation of antibody complexes by mouse DCs.20 In addition, a cancer vaccine based on coupling tumour antigens such as her-2/neu to an scFv anti-CD19 mAb has been shown to reduce tumour growth.21 Here, CD4 is linked to melanoma.