The present invention provides nucleic acids, expression systems, and vaccine strains which provide efficient expression and secretion of antigens of interest into the cytosol of host cells, and elicit effective CD4 and CD8 T cell responses by functionally linking Listerial or other bacterial signal peptides/secretion chaperones as N-terminal fusion partners in translational reading frame with selected recombinant encoded protein antigens. These N-terminal fusion partners are deleted (either by actual deletion, by mutation, or by a combination of these approaches) for any PEST sequences native to the sequence, and/or for certain hydrophobic residues.
