Live attenuated non-transmissible vaccines
The present invention provides genetically modified microorganisms with reduced transmissibility, wherein the microorganism has been genetically modified to express a single stranded binding protein (SSB) regulated by an arabinose responsive promoter, wherein the microorganism has a reduced growth capacity in the absence of arabinose.
1 . A genetically modified Salmonella enterica microorganism having reduced fecal-oral transmission, wherein the microorganism has been genetically modified to express a single stranded binding protein (SSB) regulated by a promoter that is responsive to arabinose, wherein the Salmonella enterica microorganism has a reduced growth capacity in the absence of arabinose, wherein the promoter is a P BAD promoter, wherein the microorganism has been further modified to reduce expression of endogenous AraB, AraA, and/or AraD, wherein an endogenous araBAD operon is deleted in the microorganism.
2 . The genetically modified microorganism of claim 1 , wherein the growth capacity is reduced by at least 50% in the absence of arabinose.
3 . The genetically modified microorganism of claim 1 , wherein the microorganism has been modified to express AraC.
4 . The genetically modified microorganism of claim 1 , wherein the PBAD promoter replaces the wild-type Pssb promoter.
5 . The genetically modified microorganism of claim 1 , wherein the endogenous ssb gene is inactivated or deleted.
6 . The genetically modified microorganism of claim 1 , wherein the Salmonella enterica is a typhoidal Salmonella strain.
7 . The genetically modified microorganism of claim 6 , wherein the Salmonella enterica is S. Typhi, S. Paratyphi A, and/or S. Paratyphi B.
8 . The genetically modified microorganism of claim 1 , wherein the Salmonella enterica is a non-typhoidal Salmonella (NTS) strain.
9 . The genetically modified microorganism of claim 8 , wherein the non-typhoidal Salmonella is selected from S. Typhimurium and S. Enteritidis.
10 . The genetically modified microorganism of claim 1 , wherein the microorganism comprises a mutation at a locus selected from the group consisting of guaBA, aroC, aroD, clpP, clpX, htrA, pipA, one or more capsular biosynthesis machinery genes, and combinations thereof.
11 . A pharmaceutical composition comprising the genetically modified microorganism of claim 1 and a pharmaceutically acceptable carrier.
12 . A method of inducing an immune response in a subject, comprising administering to the subject an immunologically-effective amount of the pharmaceutical composition of claim 11 .
13 . The method of claim 11 , wherein the pharmaceutical composition is orally administered.
14 . The method of claim 11 , wherein the pharmaceutical composition is intranasally administered.
15 . The method of any of claim 12 , wherein the genetic modification reduces fecal-oral transmission of the genetically modified microorganism.
16 . The method of any of claim 12 , comprising administering a combination of genetically modified microorganisms.
17 . The method of claim 16 , wherein the combination comprises a plurality of non-typhoidal Salmonella (NTS) strains.
18 . The method of claim 17 , wherein the combination comprises S. Typhimurium, S. Enteritidis S. Dublin, and S. Cholerasuis.