Patent ID: 8440207

Claim:
A live Salmonella bacterium, configured to act as a vaccine, comprising: a mutation in a genetic locus of said bacterium that attenuates virulence of said bacterium in an animal host, such that the bacterium is capable of replicating but is safe to administer to the animal host; wherein said live bacterium comprises Salmonella , wherein at least one IS200 element is deleted, and which constitutively expresses P22 phage C2 repressor without dependence on a presence of an activator or inducer molecule, to prevent new infections by bacteria phage and prevent subsequent phage transductions by bacteria phage; a DNA construct comprising a promoter nucleotide sequence, a first nucleotide sequence coding for a non-bacterial immunogenic polypeptide, wherein the nucleotide sequence coding for the non-bacterial immunogenic polypeptide has at least one codon optimized for bacterial expression with respect to its non-bacterial counterpart, and a second nucleotide sequence coding for a bacterial secretion peptide sequence, wherein the first nucleotide sequence and second nucleotide sequence are in frame and code for a fusion peptide; said bacterial secretion peptide sequence of the fusion peptide interacting with an available secretion mechanism of the bacterium, to cause a secretion of the fusion peptide from the bacterium in a form wherein the non-bacterial immunogenic polypeptide retains its immunogenicity after secretion substantially without interference of the bacterial secretion peptide sequence; the bacterium being configured to stably maintain the DNA construct and stably express and secrete the fusion peptide from the bacterium over time; the bacterium being further configured to transiently infect a local tissue of the animal, secrete the fusion peptide, and raise an immune response of the host animal to the non-bacterial immunogenic polypeptide, substantially without causing a persistent or systemic infection with the bacterium or transducing other persistent bacteria to stably secrete the fusion peptide.