The present invention is directed to a bacterial delivery system for
delivering alphavirus replicon DNA into an animal or animal cells with the
replicon encoding one or more heterologous genes to be expressed in the
animal or the animal cells. The bacteria are invasive bacteria or
attenuated invasive bacteria engineered to contain a DNA vector that
encodes the alphavirus replicon in a eukaryotic expression cassette. The
heterologous gene can encode an antigen, a therapeutic agent, an
immunoregulatory agent, an anti-sense RNA, a catalytic RNA, a protein, a
peptide, an antibody or an antigen-binding fragment of an antibody. In a
preferred embodiment, the heterologous gene encodes one or more antigens
useful as a vaccine for HIV. In addition to the bacterial delivery system,
the invention provides methods of introducing and expressing the
heterologous gene(s) in animal or animal cells and methods of stimulating
or inducing an immune response.