Signal peptide fusion partners facilitating listerial expression of antigenic sequences and methods of preparation and use thereof

A method for stimulating an immune response to a non-Listerial antigen in a human comprising:

• administering an effective amount of the Listeria bacterium to the human, the Listeria bacterium expressing the non-Listerial antigen as a fusion protein comprising:
• a polypeptide derived by recombinant modification of a secreted Listerial protein sequence, the secreted Listerial protein sequence in its unmodified form comprising a signal sequence and one or more PEST motifs, the modification comprising removal of each of the PEST motifs by deletion or substitution by one or more residues such that the polypeptide lacks any PEST motif;
• and
• a non-Listerial antigen
• wherein the non-Listerial antigen is expressed in one or more cells of the human.