Purification of staphylococcus aureus type 5 and type 8 capsular saccharides

2:

• The method of claim 1, wherein the cells are in the form of a wet cell paste or are suspended in an aqueous medium.

3:

• The method of claim 1, wherein the acid treatment is carried out using acetic acid.

4:

• The method of claim 1, wherein the acid treatment results in the capsular polysaccharide having a degree of O-acetylation between 60-100%.

5:

• The method of claim 1, wherein the method further comprises a step of neutralisation.

6:

• The method of claim 1, wherein the method further comprises a step of centrifugation of the cells and collection of the polysaccharide-containing supernatant.

7:

• A process for purifying capsular polysaccharide from S. aureus type 8 cells comprising the method of claim 1.

8:

• The process of claim 7, wherein the process further comprises a step of treatment of the capsular polysaccharide with DNase and/or RNase.

9:

• The process of claim 7, wherein the process further comprises a step of treatment of the capsular polysaccharide with mutanolysin.

10:

• The process of claim 7, wherein the process further comprises a step of diafiltration.

11:

• The process of claim 10, wherein the diafiltration is tangential flow filtration.

12:

• The process of claim 7, wherein the process further comprises a step of anion exchange chromatography.

13:

• The process of claim 7, wherein the process further comprises a step of gel filtration.

14:

• The process of claim 7, wherein the process further comprises a step of concentration of the polysaccharide.

15:

• The process of claims 7, wherein the molecular mass of the purified polysaccharide is between 2-3500 kDa.

16:

• The process of claim 7, wherein the process further comprises a step of depolymerisation of the purified polysaccharide to form an oligosaccharide.

17:

• The process of claim 7, wherein the process further comprises a step of sterile filtration.

18:

• The process of claim 7, 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.

19:

• The process of claim 18, wherein the level of peptidoglycan contamination is about 2%.

20:

• The process of claim 7, 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.

21:

• The process of claim 7, wherein the process provides a composition comprising the polysaccharide and a level of nucleic acid contamination that is less than 1% by weight nucleic acid relative to the total weight of the polysaccharide.

22:

• The process of claim 7, wherein the process further comprises a step of conjugation to a carrier molecule.

23:

• A composition comprising an S. aureus type 5 or type 8 capsular polysaccharide obtainable by the process of claims 7 or a conjugate obtainable by the process of claim