Immunogenic sequences

Abstract

The application relates to nucleic acids which encode enzymes responsible for the production of the O-antigen of Francisella tularensis , and their use as or in the production of vaccines and in diagnosis.

1 . A nucleic acid which encodes a series of enzymes or enzyme fragments which, when expressed together in a cell, are able to produce an immunogenic moiety able to produce an immune response in an animal to which it is administered, which response is protective against  Francisella tularensis  infection, the nucleic acid encoding at least one enzyme encoded by SEQ ID NOS 3-17 or modifications thereof.  
     
     
         2 . The nucleic acid of  claim 1  which encodes the enzymes encoded by SEQ ID NOS 3-17.  
     
     
         3 . The nucleic acid of  claim 1  which comprises SEQ ID NO 1 or a variant thereof.  
     
     
         4 . The nucleic acid of  claim 3  having the sequence of SEQ ID NO 1.  
     
     
         5 . The nucleic acid of  claim 1  wherein the nucleic acid comprises codons that have been optimised for expression in a bacterial cell.  
     
     
         6 . The nucleic acid of  claim 5  wherein the bacterial cell is  E. coli.    
     
     
         7 . A nucleic acid molecule comprising a fragment of SEQ ID NO 1 which may be used to detect the presence of SEQ ID NO 1 in a sample.  
     
     
         8 . The nucleic acid molecule of  claim 7  which comprises an amplification primer.  
     
     
         9 . The nucleic acid molecule of  claim 8  which is selected from the group consisting of SEQ ID NO 21, 22, 35 or 36.  
     
     
         10 . A live vaccine vector comprising a nucleic acid molecule that encodes an enzyme or enzyme fragment that when expressed in a cell, is able to produce an immunogenic moiety able to produce an immune response in an animal to which it is administered, wherein the immune response is protective against  Francisella tularensis  infection and the nucleic acid molecule encodes an enzyme encoded by SEQ ID NOS 3-17 or modifications thereof.  
     
     
         11 . The live vaccine vector of  claim 10  which comprises a bacterial vector.  
     
     
         12 . The live vaccine vector of  claim 11  wherein the bacteria is a  Salmonella  species.  
     
     
         13 . A vaccine comprising the live vaccine vector of  claim 10  in combination with a pharmaceutically acceptable carrier.  
     
     
         14 . A method of preparing a prophylactic or therapeutic vaccine, which method comprises transforming a host cell with the nucleic acid of  claim 1 , culturing said host cell and recovering a protective immunogenic moiety from the culture.  
     
     
         15 . An expression vector comprising the nucleic acid of  claim 1 .  
     
     
         16 . A host cell transformed with the vector of  claim 15 .  
     
     
         17 . A recombinant O-antigen of  F. tularensis  obtainable by the method of  claim 14 .  
     
     
         18 . A vaccine comprising the recombinant O-antigen of  claim 17  in combination with a pharmaceutically acceptable carrier.  
     
     
         19 . A method of diagnosing infection by  F. tularensis , which method comprises detecting in a sample taken from a patient suspected of having an infection the nucleic acid sequence of  claim 7 .  
     
     
         20 . A method of differentiating between strains of  F. tularensis , which method comprises selecting primers or probes which are specific for SEQ ID NO 1, and not for similar sequences in subspecies other than  F. tularensis  subspecies  tularensis , or which produce distinguishable products when used to analyse other species, and conducting an analysis using the primers or probes.  
     
     
         21 . The method of  claim 20  wherein the analysis is conducted using a polymerase chain reaction (PCR) and a pair of primers.  
     
     
         22 . The method of  claim 21  wherein the primers are specific for a start region of the nucleic acid molecule of SEQ ID NO 1.  
     
     
         23 . The method of  claim 22  wherein the primers are the nucleic acid molecules of SEQ ID NO 21 and SEQ ID NO 22.  
     
     
         24 . The method of  claim 23  wherein the primers are specific for the end transposase coding region of SEQ ID NO 1.  
     
     
         25 . The method of  claim 24  wherein the primers are the nucleic acid molecules of SEQ ID NO 35 and SEQ ID NO 36.  
     
     
         26 . Lipopolysaccharide (LPS) obtainable from  F. tularensis  subspecies  tularensis  for use as a vaccine against infection by  F. tularensis.    
     
     
         27 . The lipopolysaccharide of  claim 26  where the strain of  F. tularensis  subspecies  tularensis  is the Schu4 strain.  
     
     
         28 . A pharmaceutical composition comprising the lipopolysaccharide of  claim 26  in combination with a pharmaceutically acceptable carrier.