Abstract: Multivalent immunogenic molecules comprise a carrier molecule containing at least one functional T-cell epitope and multiple different carbohydrate fragments each linker to the carrier molecule and each containing at least one functional B-cell epitope. The carrier molecule inputs enhanced immunogenicity to the multiple carbohydrate fragments. The carbohydrate fragments may be capsular oligosaccharide fragments from Streptococcus pneumoniae, which may be serotypes 1, 4, 5, 6B, 9V, 14, 18C, 19F or 23F, or Neisseria meningitidis, which may be serotype A, B, C, W-135 or Y. Such oligosaccharide fragments may be sized from 2 to 5 kDa. Alternatively, the carbohydrate fragments may be fragments of carbohydrate-based tumor antigens, such as Globo H, LeY or STn. The multivalent molecules may be produced by random conjugation or site-directed conjugation of the carbohydrate fragments to the carrier molecule.

Abstract: Disclosed and claimed are a method for the purification of polysaccharide-protein conjugate vaccines by ultrafiltration in a saturated solution of ammonium sulfate. The ultrafiltration method of the present invention provides an efficient, readily scalable method for removal of unbound polysaccharides from polysaccharide-protein vaccines, thereby improving the purity and consistency of the polysaccharide-protein vaccines.