Polysaccharide-protein conjugate vaccines
Inventors
Lee, Che-Hung Robert • Frasch, Carl E.
Assignees
US Department of Health and Human Services
Publication Number
US-8048432-B2
Publication Date
2011-11-01
Expiration Date
2024-08-06
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Abstract
Abstract of the Disclosure Methods for synthesis and manufacture of polysaccharide-protein conjugate vaccines at high yield are provided. The methods involve reaction of a hydrazide group on one reactant with an aldehyde or cyanate ester group on the other reactant. The reaction proceeds rapidly with a high conjugation efficiency, such that a simplified purification process can be employed to separate the conjugate product from the unconjugated protein and polysaccharide and other small molecule by-products.
Core Innovation
The invention provides methods for synthesis and manufacture of polysaccharide-protein conjugate vaccines at high yield by reacting a hydrazide group on one reactant with an aldehyde or cyanate ester group on the other reactant. This reaction proceeds rapidly with high conjugation efficiency, enabling a simplified purification process to separate the conjugate product from unconjugated protein, polysaccharide, and other small molecule by-products.
The problem being solved is the low efficiency and prolonged reaction times of conventional conjugation methods, which typically achieve only about 20% yield and require extensive purification steps. Conventional methods use ε-amino groups of lysine residues on proteins to react with functional groups on activated polysaccharides, resulting in low reactivity and solubility issues. Additionally, existing vaccines based on polysaccharides have limited efficacy in young children and do not provide long-lasting protection in adults, necessitating improved protein-polysaccharide conjugate vaccines that confer long-term protection.
Claims Coverage
The patent includes one independent method claim and one independent conjugate vaccine claim, comprising multiple inventive features related to conjugation chemistry and vaccine composition.
Method for preparing a conjugate vaccine by aldehyde-hydrazide coupling
A method comprising reacting a polysaccharide with an oxidizing agent to obtain an aldehyde-activated polysaccharide, buffer exchanging to pH 7–8, reacting a protein with hydrazine or adipic acid dihydrazide in the presence of carbodiimide catalyst at pH 6–7 to obtain hydrazide-activated protein, adjusting and buffer exchanging hydrazide-protein to pH 10–11, reacting aldehyde-polysaccharide with hydrazide-protein at pH 6–8 to obtain a conjugate with C═N double bonds, and reducing these double bonds to C—N single bonds to produce a conjugate vaccine capable of stimulating an immune response.
Conjugate vaccine with polysaccharide linked to protein via specific hydrazide-based linking group
A conjugate vaccine comprising at least one polysaccharide moiety and one protein moiety, wherein the polysaccharide is linked to the protein through at least one linking group of the formula —C(═O)—NH—NH—CH2—, optionally with multiple moieties forming a crosslinked lattice structure, and capable of eliciting an immune response.
The claims cover methods employing hydrazide chemistry to efficiently prepare conjugate vaccines with improved conjugation efficiency and simplified purification, as well as the resulting conjugate vaccines characterized by specific hydrazide-based linking groups between polysaccharides and proteins.
Stated Advantages
High conjugation efficiency (typically up to about 60%), greatly increasing yield compared to conventional methods (about 20%).
Rapid reaction kinetics allowing conjugations to complete within one to two days, reducing processing time.
Simplified purification processes, potentially eliminating the need for chromatographic purification of unconjugated protein and polysaccharide.
Avoidance of sodium cyanoborohydride use, eliminating cyanide contamination in the final product.
Improved solubility and stability of activated proteins and conjugates by maintaining hydrazide-activated protein at alkaline pH during conjugation.
Production of highly immunogenic conjugate vaccines capable of eliciting strong and long-lasting immune responses in infants, children, and adults.
Reduced production costs facilitating wider vaccine availability and public health benefits.
Documented Applications
Vaccines for prevention or treatment of bacterial infections including Neisseria meningitidis (meningococcal serogroups A, B, C, W135, Y), Streptococcus pneumoniae (various serotypes), Haemophilus influenzae type b, Salmonella typhi Vi polysaccharide, and group B Streptococcus.
Vaccines for bacterial diseases such as meningitis, influenza, tetanus, and other bacterial infections.
Potential use in vaccines for other bacterial pathogens including Helicobacter pylori, Borrelia burgdorferi, Legionella pneumophilia, Mycobacteria species, Staphylococcus aureus, Neisseria gonorrhoeae, Listeria monocytogenes, Streptococcus species, Bacillus anthracis, Corynebacterium diphtheriae, and others.
Immunization of mammals, including humans and veterinary subjects, by multiple administration routes such as parenteral, intramuscular, intranasal, oral, topical, and pulmonary delivery.
Formulation into pharmaceutical compositions containing adjuvants, carriers, and excipients suitable for various modes of administration including liquid suspensions, lyophilized products, aerosols, and powders.
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