Assaying the teichoic acids of gram
The invention relates to a method for assaying the teichoic acids present, most commonly in residual form, in a preparation of Gram+ bacterial antigens. This method requires, first of all, a controlled hydrolysis with hydrofluoric acid at a temperature of less than or equal to 40° C., in order to release the oligosaccharides specific for teichoic acids. The assaying of the specific oligosaccharides can then be carried out by various techniques, in particular by high performance chromatography coupled with pulsed amperometric detection (HPAEC-PAD). The method according to the invention can in particular be used to assay the residual amounts of teichoic acids present in preparations containing capsular polysaccharides of Streptococcus pneumoniae, which may be useful as vaccines.
1. A method for quantifying the teichoic acids in a preparation comprising teichoic acids and one or more additional capsular polysaccharides of Streptococcus pneumoniae , the method comprising:
(i) treating the preparation with hydrofluoric acid (HF) at a temperature of less than or equal to 40° C., in order to release the oligosaccharides specific for the teichoic acids present in the preparation; and
(ii) quantifying the specific oligosaccharides obtained in (i).
2. The method as claimed in claim 1 , in which the preparation is treated with hydrofluoric acid (HF) at a temperature from 0° C. to 20° C.
3. The method as claimed in claim 2 , in which the preparation is treated with hydrofluoric acid (HF) at a temperature from 4° C. to 20° C.
4. The method as claimed in claim 2 , in which the preparation is treated with hydrofluoric acid (HF) at a final concentration of from 10 to 73% (weight/weight).
5. The method as claimed in claim 4 , in which the preparation is treated with hydrofluoric acid (HF) at a final concentration of between 40 and 60%.
6. The method as claimed in claim 5 , in which the preparation is treated with hydrofluoric acid (HF) at a final concentration of between 45 and 50%.
7. The method as claimed in claim 1 , wherein the specific oligosaccharides are quantified using a technique which makes it possible to quantify the monosaccharides.
8. The method as claimed in claim 7 , in which the specific oligosaccharides are quantified using high performance anion exchange chromatography (HPAEC), optionally coupled with pulsed amperometric detection (PAD).
9. The method as claimed in claim 8 , in which the HPAEC uses a support compatible with a pH greater than or equal to 12.
10. The method as claimed in claim 9 , in which the support consists of sulfonated polystyrene-divinylbenzene.
11. The method as claimed in claim 10 , in which the sulfonated polystyrene-divinylbenzene has a degree of crosslinking of 1 to 5%.
12. The method as claimed in claim 11 , in which the sulfonated polystyrene-divinylbenzene is in the form of microbeads having a diameter of 450 to 550 nm.
13. The method as claimed in claim 12 , in which the chromatography support is packaged in the form of a column and is completed, in its upper part, by a layer of a material bearing positive charges for optimizing the column resolution.
14. The method as claimed in claim 13 , in which the material for optimizing the resolution consists of material bearing a primary amine salt, a secondary amine salt, a tertiary amine salt, a quaternary ammonium salt, or an ammonium group.
15. The method as claimed in claim 14 , in which the material is latex having a degree of crosslinking of 3 to 7%.
16. The method as claimed in claim 8 , in which the HPAEC uses a material of the CARBOPAC™ ((polystyrene cross-linked with divinylbenzene) agglomerated with guaternary ammonium functionalized latex beads)) type.
17. The method as claimed in claim 16 , in which the material is a CARBOPAC™ PA1 ((polystyrene cross-linked with divinylbenzene) agglomerated with quaternary ammonium functionalized latex beads)) chromatographic column.
18. The method as claimed in claim 8 , in which the HPAEC uses an eluting solution having a pH≧12.
19. The method as claimed in claim 18 , in which the eluting solution is free of carbonate.
20. The method as claimed in claim 19 , in which the eluting solution is a sodium hydroxide solution, the molarity of which is between 10 and 300 mM.
21. The method as claimed in claim 20 , in which the sodium hydroxide solution has a molarity of between 40 and 100 mM.
22. The method as claimed in claim 1 , in which the preparation comprises one or more capsular polysaccharides of Streptococcus pneumoniae serotype 6B, 10A, 17F, 19A, 19F or 20.
23. The method as claimed in claim 22 , in which the preparation comprises a capsular polysaccharide of each one of Streptococcus pneumoniae serotypes 6B, 10A, 17F, 19A, 19F and 20.
24. The method as claimed in claim 1 , the method comprising:
(i) treating the preparation with hydrochloric acid (HF) at a temperature of less than or equal to 40° C., in order to release the teichoic acid-specific oligosaccharide present in the preparation, said specific oligosaccharides comprising the oligosaccharide specific for the C5-polysaccharide; and
(ii) quantifying the oligosaccharide specific for the C5 polysaccharide obtained in (i).
25. The method as claimed in claim 24 , in which the preparation contains a capsular polysaccharide of Streptococcus pneumoniae serotype 5.