The present invention relates to a recombinant virus of the family Paramyxoviridae comprising an expressible polynucleotide encoding at least one of (i) a tumor antigen, (ii) a fragment of a tumor antigen, and (iii) a variant of (i) or (ii). The present invention further relates to a polynucleotide encoding said recombinant virus of the family Paramyxoviridae and to a host cell comprising said recombinant virus of the family Paramyxoviridae and/or said polynucleotide encoding said recombinant virus of the family Paramyxoviridae. Moreover, the present invention relates to a method for activating immune cells with antitumor activity in a sample comprising cancer cells and to further means, methods, and uses related to the present invention.
