Generation of new BCG vaccine strains protecting against the establishment of latent
A vaccine for treating or preventing the establishment of latent tuberculosis infections is provided. The vaccine comprises a recombinant mycobacterium that overexpresses the transcription factor DosR, at a level sufficient to induce production of the dosR regulon genes or proteins. A host to whom the vaccine is administered mounts an immune response to the dosR regulon proteins and is thus protected from the establishment, persistence or reactivation of latent tuberculosis.
1. A recombinant mycobacterium comprising nucleic acid sequences encoding a DosR protein operably linked to an expression control sequence, wherein said DosR protein is over-expressed in said mycobacterium at a level sufficient to cause one or both of a 2 to 100 fold increase in transcription of one or more DosR regulon genes and a 2 to 100 fold increase in translation of one or more DosR regulon proteins encoded by said one or more DosR regulon genes in said mycobacterium.
2. The recombinant mycobacterium of claim 1 , wherein over-expression of said DosR protein is constitutive.
3. The recombinant mycobacterium of claim 1 , wherein over-expression of said DosR protein is inducible.
4. The recombinant mycobacterium of claim 1 , wherein said nucleic acid sequences encoding a DosR protein operably linked to an expression control sequence are present on a plasmid.
5. The recombinant mycobacterium of claim 1 , wherein said nucleic acid sequences encoding a DosR protein operably linked to an expression control sequence are integrated into a chromosome of said recombinant mycobacterium.
6. A method for treating latent tuberculosis infection in a patient in need thereof, comprising the step of
administering to said patient a composition comprising
a recombinant mycobacterium comprising nucleic acid sequences encoding a DosR protein operably linked to an expression control sequence; and
a physiologically acceptable carrier,
wherein said DosR protein is over-expressed in said mycobacterium at a level sufficient to cause one or both of a 2 to 100 fold increase in transcription of one or more DosR regulon genes and a 2 to 100 fold increase in translation of one or more DosR regulon proteins encoded by said one or more DosR regulon genes in said mycobacterium,
and wherein said composition is administered in a quantity sufficient to cause said patient to mount an immune response to said one or more DosR regulon proteins encoded by said one or more DosR regulon genes, thereby treating said latent tuberculosis infection.