Multivalent pneumococcal polysaccharide-protein conjugate composition

A method for making an immunogenic conjugate comprising Streptococcus pneumoniae serotype 1 polysaccharide covalently linked to a carrier protein, the method comprising:

• (a) reacting purified serotype 1 polysaccharide with a bicarbonate/carbonate buffer resulting in a partially de-O-acetylated serotype 1 polysaccharide;
• (b) reacting the partially de-O-acetylated serotype 1 polysaccharide with acetic acid resulting in a neutralized, partially de-O-acetylated serotype 1 polysaccharide;
• (c) reacting the neutralized, partially de-O-acetylated serotype 1 polysaccharide with sodium periodate resulting in an activated serotype 1 polysaccharide;
• (d) purifying the activated serotype 1 polysaccharide;
• (e) compounding the activated serotype 1 polysaccharide with a carrier protein;
• (f) co-lyophilizing the compounded, activated serotype 1 polysaccharide and carrier protein;
• (g) reacting the co-lyophilized, activated serotype 1 polysaccharide and carrier protein with sodium cyanoborohydride resulting in a serotype 1 polysaccharide:carrier protein conjugate;
• and
• (h) capping unreacted aldehydes in the serotype 1 polysaccharide:carrier protein conjugate with sodium borohydride resulting in an immunogenic conjugate comprising Streptococcus pneumoniae serotype 1 polysaccharide covalently linked to a carrier protein.

A method for making an activated Streptococcus pneumoniae serotype 1 polysaccharide, the method comprising:

• (a) reacting purified serotype 1 polysaccharide with an alkaline pH buffer resulting in a partially de-O-acetylated serotype 1 polysaccharide;
• (b) reacting the partially de-O-acetylated serotype 1 polysaccharide with a mild acid resulting in a neutralized, partially de-O-acetylated serotype 1 polysaccharide;
• and
• (c) reacting the neutralized, partially de-O-acetylated serotype 1 polysaccharide with an oxidizing agent resulting in an activated serotype 1 polysaccharide.