Self-containing lactococcus strain

Abstract

The invention relates to a recombinant Lactococcus strain, with environmentally limited growth and viability. More particularly, it relates to a recombinant Lactococcus that can only survive in a medium, where well-defined medium compounds are present. A preferred embodiment is a Lactococcus that may only survive in a host organism, where such medium compounds are present, but cannot survive outside the host organism in the absence of such medium compounds.

1 - 20 . (canceled) 
     
     
         21 . An isolated thymidylate synthase (thyA) mutant of  Lactococcus  species comprising an inactive thymidylate synthase gene and a gene or expression unit encoding a heterologous prophylactic and/or therapeutic molecule. 
     
     
         22 . The isolated thyA mutant of  Lactococcus  species according to  claim 21 , wherein the inactive thymidylate synthase gene has been inactivated by gene disruption. 
     
     
         23 . The isolated thyA mutant of  Lactococcus  species according to  claim 22 , wherein the inactive thymidylate synthase gene has been disrupted by the gene or expression unit encoding the heterologous prophylactic and/or therapeutic molecule. 
     
     
         24 . The isolated thyA mutant of  Lactococcus  species according to  claim 21 , wherein said  Lactococcus  species is  Lactococcus lactis.    
     
     
         25 . The isolated thyA mutant of  Lactococcus  species according to  claim 21 , wherein said isolated thyA mutant is transformed with a transforming plasmid, wherein said transforming plasmid does not comprise an intact thymidylate synthase gene. 
     
     
         26 . The isolated thyA mutant of  Lactococcus  species according to  claim 21 , wherein the heterologous prophylactic and/or therapeutic molecule is interleukin-10. 
     
     
         27 . A pharmaceutical composition comprising an isolated thymidylate synthase (thyA) mutant of  Lactococcus  species, said isolated thyA mutant comprising an inactive thymidylate synthase gene and a gene or expression unit encoding a heterologous prophylactic and/or therapeutic molecule. 
     
     
         28 . The pharmaceutical composition according to  claim 27 , wherein the inactive thymidylate synthase gene has been inactivated by gene disruption. 
     
     
         29 . The pharmaceutical composition according to  claim 28 , wherein the inactive thymidylate synthase gene has been disrupted by the gene or expression unit encoding the heterologous prophylactic and/or therapeutic molecule. 
     
     
         30 . The pharmaceutical composition according to  claim 27 , wherein said  Lactococcus  species is  Lactococcus lactis.    
     
     
         31 . The pharmaceutical composition according to  claim 27 , wherein said isolated thyA mutant is transformed with a transforming plasmid, wherein said transforming plasmid does not comprise an intact thymidylate synthase gene. 
     
     
         32 . The pharmaceutical composition according to  claim 27 , wherein the heterologous prophylactic and/or therapeutic molecule is interleukin-10. 
     
     
         33 . A method for delivering a prophylactic and/or therapeutic molecule to a subject, the method comprising administering to the subject an isolated thymidylate synthase (thyA) mutant of  Lactococcus  species comprising an inactive thymidylate synthase gene and a gene or expression unit encoding the heterologous prophylactic and/or therapeutic molecule. 
     
     
         34 . The method according to  claim 33 , wherein the inactive thymidylate synthase gene has been inactivated by gene disruption. 
     
     
         35 . The method according to  claim 34 , wherein the inactive thymidylate synthase gene has been disrupted by the gene or expression unit encoding the heterologous prophylactic and/or therapeutic molecule. 
     
     
         36 . The method according to  claim 33 , wherein said  Lactococcus  species is  Lactococcus lactis.    
     
     
         37 . The method according to  claim 33 , wherein said isolated thyA mutant is transformed with a transforming plasmid, wherein said transforming plasmid does not comprise an intact thymidylate synthase gene. 
     
     
         38 . The method according to  claim 33 , wherein the heterologous prophylactic and/or therapeutic molecule is interleukin-10. 
     
     
         39 . A method for treating inflammatory bowel disease in a subject, the method comprising administering to the subject an isolated thymidylate synthase (thyA) mutant of  Lactococcus  species comprising an inactive thymidylate synthase gene and a gene or expression unit encoding the heterologous prophylactic and/or therapeutic molecule. 
     
     
         40 . The method according to  claim 39 , wherein the inactive thymidylate synthase gene has been inactivated by gene disruption. 
     
     
         41 . The method according to  claim 40 , wherein the inactive thymidylate synthase gene has been disrupted by the gene or expression unit encoding the heterologous prophylactic and/or therapeutic molecule. 
     
     
         42 . The method according to  claim 39 , wherein said  Lactococcus  species is  Lactococcus lactis.    
     
     
         43 . The method according to  claim 39 , wherein said isolated thyA mutant is transformed with a transforming plasmid, wherein said transforming plasmid does not comprise an intact thymidylate synthase gene. 
     
     
         44 . The method according to  claim 39 , wherein the heterologous prophylactic and/or therapeutic molecule is interleukin-10.