Attenuated mycoplasma gallisepticum strains

Abstract

The present invention provides live, attenuated Mycoplasma gallisepticum bacteria that exhibit reduced expression of a protein identified as MGA_0621. In certain embodiments, the attenuated bacteria may additionally exhibit reduced expression of one or more proteins selected from the group consisting of pyruvate dehydrogenase, phosphopyruvate hydratase, 2-deoxyribose-5-phosphate aldolase, and ribosomal protein L35, relative to a wild-type M. gallisepticum bacterium. Also provided are vaccines and vaccination methods involving the use of the live, attenuated M. gallisepticum bacteria, and methods for making live attenuated M. gallisepticum bacteria. An exemplary live, attenuated strain of M. gallisepticum is provided, designated MGx+47, which was shown by proteomics analysis to exhibit significantly reduced expression of MGA_0621, and was shown to be safe and effective when administered as a vaccine against M. gallisepticum infection in chickens.

1 - 38 . (canceled) 
     
     
         39 . A method of attenuating  Mycoplasma gallisepticum  bacteria, said method comprising: subjecting an initial population of  Mycoplasma gallisepticum  bacteria to attenuating conditions wherein said conditions decrease the level of a protein having the amino acid sequence comprising SEQ ID NO: 1 in said  Mycoplasma gallisepticum  bacteria. 
     
     
         40 . The method of  claim 39  wherein said attenuating conditions comprise passaging said initial population of  Mycoplasma gallisepticum  bacteria at least 2 times in vitro. 
     
     
         41 . The method of  claim 39 , wherein said attenuating conditions comprise passaging said initial population of  Mycoplasma gallisepticum  bacteria at least 5 times in vitro. 
     
     
         42 . The method of  claim 39 , wherein said attenuating conditions comprise passaging said initial population of  Mycoplasma gallisepticum  bacteria at least 10 times in vitro. 
     
     
         43 . The method of  claim 39  wherein said attenuating conditions comprise passaging said initial population of  Mycoplasma gallisepticum  bacteria at least 20 times in vitro. 
     
     
         44 . The method of  claim 39  wherein said attenuating conditions comprise passaging said initial population of  Mycoplasma gallisepticum  bacteria at least 30 times in vitro. 
     
     
         45 . The method of  claim 39  wherein said attenuating conditions comprise passaging said initial population of  Mycoplasma gallisepticum  bacteria at least 40 times in vitro. 
     
     
         46 . The method of  claim 39 , wherein said attenuating conditions comprise transforming said initial population of  Mycoplasma gallisepticum  with a transposon which randomly inserts into the  Mycoplasma gallisepticum  genome. 
     
     
         47 . The method of  claim 39 , wherein said attenuating conditions comprise exposing said initial population of  Mycoplasma gallisepticum  to a chemical mutagen or ultra violet light. 
     
     
         48 . A live, attenuated  Mycoplasma gallisepticum  bacteria produced by the method of  claim 39 . 
     
     
         49 . A vaccine composition comprising the attenuated  Mycoplasma gallisepticum  bacteria of  claim 39  and a pharmaceutically acceptable carrier. 
     
     
         50 . A method of vaccinating an animal to prevent  Mycoplasma gallisepticum  infection said method comprising administering an immunologically effective amount of the vaccine composition of  claim 49 . 
     
     
         51 . The method of  claim 50  wherein said vaccine composition is administered to said animal by direct injection, spray administration or drinking water administration.