| abstract |
Capsular saccharides derived from serogroups W135 and Y of Neisseria meningitidis have altered levels of O-acetylation at the 7 and 9 positions of their sialic acid residues, and can be used to make immunogenic compositions. Relative to unmodifed native saccharides, derivatives of the invention are preferentially selected during conjugation to carrier proteins, and conjugates of the derivatives show improved immunogenicity compared to native polysaccharides. |