Antigenic group B streptococcus type II and type III polysaccharide fragments having a 2,5-anhydro-D-mannose terminal structure and conjugate vaccine thereof
AssigneeNorth American Vaccine, Inc.
InventorsFrancis Michon, Catherine Dong, Joseph Y. Tai
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Abstract
The process for depolymerizing Group B Types II and III Streptococcus is disclosed which results in polysaccharide fragments having a reducing end suitable for conjugating to protein. Conjugate molecules, vaccines and their use to immunize mammals including humans are also disclosed.
Claims13
A process for depolymerizing Group B Streptococcus (GBS) type II and type III polysaccharides to produce fragments having the following 2,5-anhydro-D mannose reducing-end structure,
- wherein R1 is H and R2 is sialylated heptasaccharide repeating-unit of formula
- wherein n is about 5 to about 50 for the type II, and where R1 is sialylated pentasaccharide repeating-units of formula
- wherein n is about 5 to 50 and R2 is disaccharide αNeuAc(2-3)β-D-Galp1- for the type III,
- said process comprising the steps of
- providing a GBS type II or GBS type III polysaccharide to be depolymerized and reacting the polysaccharide in an aqueous medium with a base to form a partially de-N-acetylated polysaccharide product, depolymerizing the de-N-acetylated product with a nitrosation agent to form the GBS type II or type III fragments, and
- recovering the fragments.
A Group B Streptococcus (GBS) type II or type III polysaccharide fragment prepared by the process comprising the steps of
- providing a GBS type II or GBS type III polysaccharide to be depolymerized having the following structure:
- wherein n for native type II polysaccharide is about 200;
- and the repeating unit for GBS type III
- wherein n for native type III polysaccharide is about 100;
- reacting the Polysaccharide in an aqueous medium with a base to form a partially de-N-acetylated polysaccharide product, and;
- depolymerizing the de-N-acetylated product with a nitrosation agent to form the GBS type II or type III fragment.
A Group B Streptococcus (GBS) type II or type III polysaccharide fragment having the following 2,5-anhydro-D mannose reducing-end structure,
- wherein R1 is H and R2 is sialylated heptasaccharide repeating-unit of formula
- wherein n is about 5 to about 50 for the type II, and where R1 is sialylated pentasaccharide repeating-units of formula
- wherein n is about 5 to 50 and R2 is disaccharide αNeuAc(2-3)β-D-Galp1- for the type III.
Dependencies are inferred from the claim text.