abstract |
Disclosed is a modified serogroup W135 meningococcal capsular saccharide conjugated to a carrier protein, wherein: (a) < 29% of the sialic acid residues in the saccharide are O-acetylated at the 7 position; and/or (b) > 26% of the sialic acid residues in the saccharide are O-acetylated at the 9 position. Also disclosed a modified meningococcal capsular saccharide, wherein the saccharide comprises n or more repeating units of the disaccharide unit: [sialic acid] - [hexose] where the hexose is either galactose or glucose and n is an integer from 1 to 100, and wherein: (a) < x% of the sialic acid residues in said n or more repeating units are O-acetylated at the 7 position; and/or (b) when hexose is galactose, > y% of the sialic acid residues in said n or more repeating units are O-acetylated at the 9 position, and when hexose is glucose, > y% or < z% of the sialic acid residues in said n or more repeating units are O-acetylated at the 9 position, where: when hexose is galactose, x is 29 and y is 26; and when hexose is glucose, x is 9, y is 29 and z is 27. |