| 摘要 |
Disclosed are conjugates obtained by reductive amination of serotype 5 pneumococcus capsular polysaccharide. The reductive amination conditions differ from conventional conditions in that they avoid the creation of an undesired compound which is harmful to the immunogenicity of the conjugates. In carbon NMR spectrometry, the undesired compound is characterized by a resonance signal of 13 -14 ppm. The aminated polysaccharides involved in the production of the conjugates have a carbon NMR spectrum devoid of a resonance signal of 13 -14 ppm. The reductive amination conditions are twofold. According to a first method, the reductive amination is performed at a pH which is slightly acidic (4-6.5) for a maximum of 4 hours. According to a second method, the polysaccharide is initially reduced, then fragmented and finally undergoes the reductive amination per se in conventional or unconventional conditions. According to the method used, the structure of the aminated polysaccharide can vary (conversion or not of the Sug residue of the repeater unit into N-acetyl quinovosamine and N-acetyl fucosamine) but said variations, as recorded in carbon NMR spectrometry, have no effect on immunogenicity.
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