Measuring degree of polymerisation for meningococcal capsular saccharides that contain sialic acid
AssigneeNovartis Vaccines and Diagnostics, Inc.
InventorAngela Bardotti
Life of this patent
Estimating the term…
Abstract
The degree of polymerisation (DP) is an important parameter for analysis of saccharide antigens, particularly in glycoconjugates. The invention provides methods that can be used to measure DP for capsular saccharides, particularly for meningococcal saccharides e.g. from serogroups W135 and Y. A preferred method is based on reduction of terminal sialic acid residues on saccharides, with DP then being calculated by comparing the molar ratio of total sialic acid to reduced sialic acid.
Claims39
A process for measuring the degree of polymerisation of a capsular saccharide, wherein:
- (a) the saccharide comprises sialic acid monosaccharide subunits that are linked α2→9;
- (b) the saccharide has a terminal sialic acid monosaccharide subunit;
- and (c) the process comprises the steps of:
- (i) reducing the terminal sialic acid monosaccharide subunit to give a reduced sialic acid monosaccharide subunit;
- (ii) chemically hydrolysing the saccharide to give a hydrolysate containing monosaccharide subunits, wherein the hydrolysis proceeds to completion to yield only monosaccharide subunits;
- (iii) determining the ratio of total sialic acid to reduced sialic acid in the hydrolysate.
A process for measuring the degree of polymerisation of a capsular saccharide, wherein:
- (a) the saccharide comprises sialic acid monosaccharide subunits and non-sialic acid monosaccharide subunits;
- (b) the saccharide has a terminal sialic acid monosaccharide subunit;
- and (c) the process comprises the steps of:
- (i) modifying a terminal sialic acid subunit of the saccharide, to give a modified terminal sialic acid subunit;
- (ii) hydrolysing the saccharide to give a saccharide hydrolysate containing sialic acid subunits, including modified terminal sialic acid subunits, wherein the hydrolysis proceeds to completion to yield only monosaccharide subunits;
- (iii) quantifying the sialic acid subunits from the hydrolysate, including the modified terminal sialic acid subunits;
- and (iv) using the quantitative results of step (iii) to calculate the degree of polymerisation.
A process for measuring the degree of polymerisation (DP) of a capsular saccharide from meningococcal serogroup W135 or serogroup Y, wherein the process comprises the steps of:
- (i) hydrolysing the saccharide to give a saccharide hydrolysate containing monosaccharide subunits, wherein the hydrolysis proceeds to completion to yield only monosaccharide subunits;
- (ii) quantifying the monosaccharide subunits in the hydrolysate, wherein the quantitative results of step (ii) are used to calculate the degree of polymerisation.
Dependencies are inferred from the claim text.