Capsular polysaccharide solubilisation and combination vaccines
Precipitated bacterial capsular polysaccharides can be efficiently re-solubilised using alcohols as solvents. The invention provides a process for purifying a bacterial capsular polysaccharide, comprising the steps of (a) precipitation of said polysaccharide, followed by (b) solubilisation of the precipitated polysaccharide using ethanol. CTAB can be used for step (a). The material obtained, preferably following hydrolysis and sizing, can be conjugated to a carrier protein and formulated as a vaccine. Also, in vaccines comprising saccharides from both serogroups A and C, the invention provides that the ratio (w/w) of Men A saccharide:MenC saccharide is >1.
1. A liquid composition comprising a Neisseria meningitidis serogroup A capsular saccharide conjugate and a Neisseria meningitidis serogroup C capsular saccharide conjugate, and further comprising (i) an aluminum hydroxide adjuvant and (ii) a histidine buffer, and where each conjugate has a saccharide:protein ratio (w/w) of between 0.5:1 and 5:1.
2. The composition of claim 1 , wherein each conjugate comprises capsular saccharides that are oligosaccharides with an average degree of polymerization of less than 30 conjugated to the carrier protein selected from bacterial toxins and toxoids.
3. The composition of claim 2 , wherein the bacterial toxins and toxoids are diphtheria toxoids or tetanus toxoids.
4. The composition of claim 1 , wherein each conjugate comprises a linker.
5. The composition of claim 1 , wherein the capsular saccharide in each conjugate was activated or functionalized prior to conjugation.
6. The composition of claim 5 , wherein the activation was with a cyanylating reagent.
7. The composition of claim 1 , wherein the composition comprises Neisseria meningitidis serogroup A capsular saccharides, Neisseria meningitidis serogroup C capsular saccharides, Neisseria meningitidis serogroup W135 capsular saccharides, and Neisseria meningitidis serogroup Y capsular saccharides.
8. The composition of claim 1 , wherein the composition further comprises proteins from serogroup B of Neisseria meningitidis.
9. The composition of claim 1 , wherein the composition further comprises antigens from pneumococcus, hepatitis A virus, hepatitis B virus, Bordetella pertussis , diphtheria, tetanus, Helicobacter pylori , polio and/or Haemophilus influenzae.