An autologous dendritic cell (DC) cancer vaccine with potential immunostimulatory activity. Anti-CTLA4 MoAb RNA-transfected autologous DC vaccine is prepared by transfecting DCs with RNAs encoding humanized heavy and light chains of the anti-CTLA4 (cytotoxic T-Lymphocyte-Associated Antigen 4); expression of anti-CTLA4 blocks the inhibitory effect of CTLA4 on the activation of T-lymphocytes. Co-vaccination of this vaccine with melanoma antigen specific vaccine may eliminate the adverse effects associated with systemic administration of immune modulators, while also enhancing vaccine-induced immune responses.