Fusion of non-hemolytic, truncated form of listeriolysin O to antigens to enhance immunogenicity

A method for enhancing the cell-mediated immunogenicity of a tumor antigen, wherein the cell-mediated immunogenicity comprises major histocompatability class I presentation of the tumor antigen, the method comprising fusing to the tumor antigen a non-hemolytic truncated form of listeriolysin O by recombinant expression of a plasmid encoding the truncated form of the listeriolysin O and the tumor antigen in a host cell other than listeria or by a nonlisteria vector system or by chemical conjugation of the tumor antigen to the truncated form of the listeriolysin O, wherein the amino acid sequence of the non-hemolytic truncated form of listeriolysin O consists the amino acid sequence set forth in SEQ ID NO:2.