Genetic alteration of Mycobacterium smegmatis to improve mycobacterium-mediated transfer of plasmid DNA into mammalian cells and DNA immunization.

Mycobacteria target and persist within phagocytic monocytes and are strong adjuvants, making them attractive candidate vectors for DNA vaccines. We characterized the ability of mycobacteria to deliver transgenes to mammalian cells and the effects of various bacterial chromosomal mutations on the efficiency of transfer in vivo and in vitro. First, we observed green fluorescent protein expression via microscopy and fluorescence-activated cell sorting analysis after infection of phagocytic and nonphagocytic cell lines by Mycobacterium smegmatis or M.

Mucosal immunization with attenuated Shigella flexneri harboring an influenza hemagglutinin DNA vaccine protects mice against a lethal influenza challenge.

Mucosal surfaces are important for the induction of immunity against influenza virus. In a murine intranasal immunization model, we demonstrated that the attenuated Shigella flexneri Deltaasd strain 15D, carrying a DNA construct encoding the influenza virus hemagglutinin (HA), induces protective immunity against a lethal respiratory challenge with influenza A/WSN/33. Influenza virus-specific IFN-gamma T cells were detected among splenocytes, and anti-HA IgG was detected in serum post-immunization, albeit at low levels.

Mucosal DNA vaccination with highly attenuated Shigella is superior to attenuated Salmonella and comparable to intramuscular DNA vaccination for T cells against HIV.

An immunization strategy using attenuated bacteria to deliver DNA vaccine plasmids to mucosal sites may induce protective T cell responses against sexual HIV transmission. In a murine intranasal (i.n.