Abstract: Provided herein are prime-boost regimens and materials used therein. The prime-boost regimens enhance the immune response to a target antigen. The vaccines used for boost are comprised of recombinant attenuated metabolically active Listeria that encodes an expressible antigen that is cross-reactive with the target antigen. In some examples, the immune response is a cellular immune response.

Abstract: The invention provides Listeria that, in addition to comprising polynucleotides that encode heterologous polypeptides such as tumor or infectious agent antigens, have been modified to express holin proteins that facilitate the delivery of the heterologous polypeptides, or polynucleotides encoding the same, outside of the bacteria. In some particular embodiments, the Listeria generate viral-derived, self-replicating RNAs that direct expression of the heterologous polypeptides in the cytosol of infected cells. Methods of using the Listeria, and compositions thereof, to induce immune response and/or in the prevention or treatment of disease are also provided. Methods of producing the bacteria are also provided.

Abstract: The present invention provides Listeria that are attenuated for entry into non-phagocytic cells as well as a variety of methods of inducing immune responses involving administering compositions comprising the attenuated Listeria. Some of the attenuated Listeria are mutant Listeria that comprise at least one mutation in a gene encoding an invasin, such as an internalin. Some of the attenuated Listeria are further attenuated for cell-to-cell spread. Pharmaceutical compositions and vaccines useful in the methods of the invention are further provided. Methods of making and improving vaccines are also provided.