A recombinant Listeria strain expressing a fusion polypeptide, wherein the fusion polypeptide comprises a heterologous antigen fused to an N-terminal LLO, wherein the recombinant Listeria is an attenuated Listeria which comprises a mutation in the dal/dat genes, a metabolic enzyme that complements the dal/dat mutation, and a mutation or deletion of the endogenous actA gene, and medical uses thereof. The heterologous antigen may be Prostate Specific Antigen (PSA).
