DC‐based vaccination alone has been shown to depend on NK cell activation to provide cytokines such as IFNγ that induce a Th1/CTL response.27 In the combination therapy, however, local infection of tumor tissue by VSV‐GP induced type‐I IFN, and thereby a Th1 switch.45 This occurred even in the absence of a DC/NK cell cross‐talk, which could be the reason that NK cells are not essential for the therapeutic efficacy of the combination treatment. This evidence concerns the gene IFNG and infection.