Conjugation of Staphylococcus aureus type 5 and type 8 capsular polysaccharides
AssigneeNovartis AG
InventorsFrancesco Berti, Paolo Costantino, Maria Rosaria Romano
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Abstract
The invention provides a process for preparing a conjugate of a S. aureus type 5 or type 8 capsular polysaccharide and a carrier molecule, comprising the steps of: (a) depolymerizing the capsular polysaccharide, to give a polysaccharide fragment; (b) oxidizing the fragment in order to introduce an aldehyde group into at least one saccharide residue in the fragment, to give an oxidized saccharide residue; and (c) coupling the oxidized saccharide residue to a carrier molecule via the aldehyde group, thereby giving the conjugate. The coupling in step (c) may be direct, or may be via a linker molecule. The invention also provides a conjugate obtained or obtainable by this process.
Claims14
A process of preparing a conjugate of an isolated fragment of the type 5 capsular polysaccharide of Staphylococcus aureus and a carrier molecule comprising the steps of (a) depolymerising an isolated full-length type 5 capsular polysaccharide of S. aureus to provide an isolated fragment of the type 5 capsular polysaccharide having a molecular mass of between 5 kDa and 100 kDa;
- (b) oxidising the fragment of the type 5 capsular polysaccharide in order to introduce an aldehyde group into at least one saccharide residue in the fragment to have at least one oxidised saccharide residue in the fragment;
- and (c) coupling the fragment having the at least one oxidised saccharide residue to the carrier molecule via the aldehyde group, thereby preparing the conjugate.
A process of producing a purified fragment of a type 5 capsular polysaccharide of Staphylococcus aureus comprising the step of depolymerizing a purified full-length type 5 S. aureus capsular polysaccharide by acid hydrolysis under conditions suitable for the depolymerization, thereby producing the fragment of the purified type 5 capsular polysaccharide of S. aureus, wherein the fragment has a □-D-FucNAc-(1→moiety at its non-reducing terminus.
A method of providing an oxidised Staphylococcus aureus type 5 capsular polysaccharide comprising the step of oxidising an isolated S. aureus type 5 capsular polysaccharide having a □-D-FucNAc-(1→moiety at its non-reducing terminus to convert the two vicinal hydroxyl groups in the □-D-FucNAc-(1→moiety into two aldehyde groups.
A process of providing a coupled Staphylococcus aureus type 5 capsular polysaccharide comprising the step of coupling to a carrier molecule an isolated S. aureus type 5 capsular polysaccharide having a □-D-FucNAc-(1→moiety at its non-reducing terminus that has been oxidised to convert its two vicinal hydroxyl groups into two aldehyde groups, wherein the coupling is via one of the aldehyde groups.
Dependencies are inferred from the claim text.