Staphylococcus aureus type 8 capsular saccharides

Abstract

The invention provides a method for releasing capsular polysaccharide from S. aureus type 5 or type 8 cells, comprising the step of treating the cells with acid. The invention further provides a process for purifying capsular polysaccharide from S. aureus type 5 or type 8 cells comprising this method. Other processing steps may be included in the process, such as enzymatic treatment, e.g. to remove nucleic acid, protein and/or peptidoglycan contaminants; diafiltration, e.g. to remove low molecular weight contaminants; anion exchange chromatography, e.g. to remove residual protein; and concentration.

1 - 26 . (canceled) 
     
     
         27 . A composition comprising an  S. aureus  type 8 capsular polysaccharide obtainable by a process comprising the step of treating the cells with acid, wherein the acid treatment results in the capsular polysaccharide having a degree of O-acetylation between 60-100%. 
     
     
         28 . The composition of  claim 27  further comprising one or more  S. aureus  protein antigen(s) selected from the group consisting of a clfA antigen; a clfB antigen; a sdrE2 antigen; a sdrC antigen; a sasF antigen; a emp antigen; a sdrD antigen; a spa antigen; a esaC antigen; a esxA antigen; a esxB antigen; a sta006 antigen; a isdC antigen; a Ma antigen; a sta011 antigen; a isdA antigen; a isdB antigen; and a sta073 antigen. 
     
     
         29 . The composition of  claim 27 , wherein the composition comprises  S. aureus  protein antigens according to one of combinations (1) to (10) below:
 (1) a esxA antigen, a esxB antigen, a sta006 antigen and a Hla antigen;   (2) a esxA antigen, a esxB antigen, a sta006 antigen and a sta011 antigen;   (3) a esxA antigen, a esxB antigen and a sta011 antigen;   (4) a esxA antigen, a esxB antigen, a Hla antigen, a sta006 antigen and a sta011 antigen;   (5) a esxA antigen, a esxB antigen and a Hla antigen;   (6) a Hla antigen, a sta006 antigen and a sta011 antigen;   (7) a esxA antigen and a esxB antigen;   (8) a esxA antigen, a esxB antigen and a sta006 antigen;   (9) a esxA antigen, a esxB antigen, a sta011 antigen and a sta073 antigen; and   (10) a sta006 antigen and a sta011 antigen.   
     
     
         30 . The composition of  claim 27 , wherein the cells are in the form of a wet cell paste or are suspended in an aqueous medium. 
     
     
         31 . The composition of  claim 27 , wherein the acid treatment is carried out using acetic acid. 
     
     
         32 . The composition of  claim 27 , wherein the process further comprises a step of neutralization after said treating with acid. 
     
     
         33 . The composition of  claim 27 , wherein the process further comprises a step of centrifugation of the cells and collection of the polysaccharide-containing supernatant after said treating with acid. 
     
     
         34 . The composition of  claim 27 , wherein the process further comprises a step of treatment of the capsular polysaccharide with DNase and/or RNase after said treating with acid. 
     
     
         35 . The composition of  claim 27 , wherein the process further comprises a step of treatment of the capsular polysaccharide with mutanolysin after said treating with acid. 
     
     
         36 . The composition of  claim 27 , wherein the process further comprises a step of diafiltration after said treating with acid. 
     
     
         37 . The composition of  claim 36 , wherein the diafiltration is tangential flow filtration. 
     
     
         38 . The composition of  claim 27 , wherein the process further comprises a step of anion exchange chromatography after said treating with acid. 
     
     
         39 . The composition of  claim 27 , wherein the process further comprises a step of gel filtration after said treating with acid. 
     
     
         40 . The composition of  claim 27 , wherein the process further comprises a step of concentration of the polysaccharide after said treating with acid. 
     
     
         41 . The composition of  claim 27 , wherein the process further comprises a step of depolymerisation of the polysaccharide to form an oligosaccharide after said treating with acid. 
     
     
         42 . The composition of  claim 27 , wherein the process provides a composition comprising the polysaccharide and a level of peptidoglycan contamination that is less than 5% by weight peptidoglycan relative to the total weight of the polysaccharide. 
     
     
         43 . The composition of  claim 42 , wherein the level of peptidoglycan contamination is about 2%. 
     
     
         44 . The composition of  claim 27 , wherein the process provides a composition comprising the polysaccharide and a level of protein contamination that is less than 5% by weight protein relative to the total weight of the polysaccharide. 
     
     
         45 . The composition of  claim 27 , wherein the process further comprises a step of conjugation of the polysaccharide to a carrier molecule after said treating with acid.