Methods for making saccharide-protein glycoconjugates

摘要

The invention provides a process for the reductive amination of a carbonyl group at the reducing terminus of a polysaccharide, wherein the reductive amination is carried out at a pH between 4 and 5. The invention also provides a process for preparing a conjugate of a polysaccharide and a carrier molecule, comprising the steps of: (a) coupling the polysaccharide to a linker, to form a polysaccharide-linker compound in which the free terminus of the linker is an ester group; and (b) reacting the ester group with a primary amine group in the carrier molecule, to form a polysaccharide-linker-carrier molecule conjugate in which the linker is coupled to the carrier molecule via an amide linkage. The invention also provides a process for reducing contamination of a polysaccharide-linker compound with unreacted linker, comprising a step of precipitating unreacted linker under aqueous conditions at a pH of less than 5.

主权项

1. A process for the reductive amination of a carbonyl group at the reducing terminus of a polysaccharide, comprising:
combining the polysaccharide with a primary amine group in the presence of a reducing agent,
wherein the polysaccharide comprises:
a core domain from a lipopolysaccharide of a Gram-negative bacterium; anda carbonyl group at the reducing terminus, and reacting the carbonyl group with the primary amine group by reductive amination,
wherein the reductive amination is carried out at a pH between 4 and 5.