Patent ID: 8603484

Claim:
A method for making a multivalent immunogenic composition comprising polysaccharide-protein conjugates, wherein each of the conjugates comprises a capsular polysaccharide from a different serotype of Streptococcus pneumoniae conjugated to a carrier protein, and the capsular polysaccharides are prepared from serotype 3 and at least one additional serotype, the method comprising: (a) reacting purified serotype 3 polysaccharide with a mild acid resulting in a hydrolyzed serotype 3 polysaccharide; (b) reacting the hydrolyzed serotype 3 polysaccharide with an oxidizing agent in the presence of bivalent cations resulting in an activated serotype 3 polysaccharide; (c) compounding the activated serotype 3 polysaccharide with a carrier protein; (d) reacting the compounded, activated serotype 3 polysaccharide and carrier protein with a reducing agent resulting in a serotype 3 polysaccharide:carrier protein conjugate; and (e) capping unreacted aldehydes in the serotype 3 polysaccharide:carrier protein conjugate resulting in an immunogenic conjugate comprising Streptococcus pneumoniae serotype 3 polysaccharide covalently linked to a carrier protein; and (f) compounding the immunogenic conjugate comprising Streptococcus pneumoniae serotype 3 polysaccharide and at least one immunogenic conjugate comprising an additional Streptococcus pneumoniae serotype polysaccharide resulting in a multivalent immunogenic composition.