The present invention relates to the use of Whole inactivated influenza virus (WIV) for use as adjuvant when raising an immune response to an antigen. The WIV is preferably used as adjuvant for raising a cellular immune response such as a CTL response against the antigen, preferably using a peptide comprising an epitope of the antigen as immunogen. The antigen can be an antigen of a tumor or of an infectious agent, e.g. a virus such as influenza virus. The WIV is particularly suitable for raising a cellular immune response against conserved, preferably non-surface exposed, epitopes of viruses such as influenza.