Methods for preparing complex multivalent immunogenic conjugates
Inventors
Assignees
US Department of Health and Human Services
Publication Number
US-8173135-B2
Publication Date
2012-05-08
Expiration Date
2027-03-16
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Abstract
Methods for preparing complex multivalent immunogenic conjugates that include simultaneously reacting a plurality or immunogenic-distinct polysaccharides with at least one protein to make the complex multivalent immunogenic conjugates. The simultaneous reaction involves reaction of a hydrazide group on one reactant with an aldehyde or cyanate ester group on the other reactant.
Core Innovation
The invention relates to methods for preparing complex multivalent immunogenic conjugates, including conjugate vaccines, by simultaneously reacting a plurality of immunogenic-distinct polysaccharides with at least one protein. The simultaneous reaction involves the reaction of a hydrazide group on one reactant with an aldehyde or cyanate ester group on the other reactant, forming conjugates through C═N double bonds that are subsequently reduced to C—N bonds, yielding complex multivalent immunogenic conjugate products.
The problem being solved arises from limitations of conventional polysaccharide-protein conjugate vaccine production methods, which have low efficiency (typically about 20%) and require lengthy reaction times and multiple purification steps. Native bacterial polysaccharides alone induce only short-term immunity due to their T-independent nature, and existing conjugation chemistries employing amino groups on proteins yield low conjugation efficiency, high protein and polysaccharide losses, precipitation issues, and low yields. There is a need for improved methods that yield high conjugation efficiency, faster reaction rates, fewer undesired by-products, and reduced purification requirements.
Claims Coverage
The claims include 34 inventive features focused on novel methods of synthesizing complex multivalent immunogenic conjugates through hydrazide chemistry and the resultant conjugate structures, emphasizing simultaneous reactions of multiple immunogenic-distinct polysaccharides and enhanced protein activation conditions.
Simultaneous conjugation of multiple aldehyde-activated polysaccharides with hydrazide-activated proteins
The method comprises reacting a plurality of immunogenic-distinct polysaccharides with an oxidizing agent to produce aldehyde-activated polysaccharides, reacting at least one protein with hydrazine or related hydrazides to produce hydrazide-activated protein, contacting these under pH 5-8 to simultaneously form C═N double bonds, and reducing these bonds to form a stable complex multivalent immunogenic conjugate.
Hydrazide-activated protein soluble at neutral pH
Preparation of hydrazide-activated protein soluble at neutral pH by reacting protein with hydrazine, carbohydrazide, hydrazine chloride, dihydrazides or mixtures thereof in the presence of a carbodiimide and amino acids or peptides, with amino acids selected from lysine, arginine, histidine, glycine, serine, threonine, glutamic acid, or cysteine.
Activation of proteins at controlled pH to improve conjugation stability
Methods involving reacting proteins with hydrazine, carbohydrazide, succinyl dihydrazide, adipic acid dihydrazide or mixtures in the presence of carbodiimide hydrochloride at pH 5.5–7 followed by buffer exchange to pH 10–11 to obtain soluble hydrazide-activated proteins suitable for conjugation.
Simultaneous reaction of 2 to 28 polysaccharides with hydrazide-activated proteins
Methods wherein 2 to 28 immunogenic-distinct polysaccharides, including meningococcal, pneumococcal, Haemophilus influenzae type b, Vi polysaccharide of Salmonella typhi and group B Streptococcus polysaccharides, are conjugated simultaneously with hydrazide-activated proteins to form complex multivalent immunogenic conjugates.
Sequential conjugation to address polysaccharide reactivity differences
A method where less reactive aldehyde-activated polysaccharides are first conjugated to hydrazide-activated protein forming an intermediate, followed by reaction with more reactive polysaccharides, with subsequent reduction of all C═N bonds to C—N bonds to form the final complex conjugate.
Conjugation reaction without cyanoborohydride by using hydrazide chemistry
Avoiding the use of sodium cyanoborohydride in reductive amination by exploiting the high efficiency of hydrazide-aldehyde reactions, thus preventing cyanide contamination and enabling mild conjugation conditions and higher yields.
Single-batch simultaneous conjugation of multivalent polysaccharide mixtures
Simplifying multivalent conjugate vaccine preparations by simultaneously conjugating mixtures of immunogenic-distinct polysaccharides in a single reaction batch with hydrazide-activated proteins, reducing production costs and facilitating manufacturing and administration.
Conjugate vaccines including multiple immunogenic-distinct polysaccharides attached to single or multiple proteins
Producing conjugates where multiple distinct polysaccharides are covalently attached either to a single protein molecule or construct, or as mixtures of conjugates with separate polysaccharide-protein components, enhancing immunogenicity and vaccine coverage.
The claims define innovative hydrazide chemistry-based methods for preparing complex multivalent immunogenic conjugates by simultaneous or sequential reaction of multiple aldehyde-activated polysaccharides with hydrazide-activated proteins, improved protein activation techniques for solubility and stability, and the resultant multivalent conjugates comprising multiple distinct polysaccharides conjugated to single or multiple proteins, thereby addressing inefficiencies and limitations of prior conjugate vaccine manufacturing processes.
Stated Advantages
High efficiency and yield of polysaccharide-protein conjugation reactions, typically as high as about 60%, reducing loss of reactants.
Rapid conjugation reaction completion within one to three days under mild conditions, compared to days in traditional methods.
Reduced or unnecessary purification steps, simplifying manufacturing and lowering production costs.
Improved solubility and stability of hydrazide-activated proteins at neutral or alkaline pH, reducing protein aggregation and precipitation.
Avoidance of toxic reagents such as sodium cyanoborohydride, thereby eliminating cyanide contamination in conjugate vaccines.
Capability to prepare complex multivalent conjugate vaccines in a single batch by simultaneous conjugation of multiple polysaccharides, improving scalability and logistics.
Enhanced immunogenicity and induction of long-lasting antibody responses, including in infants, against multiple bacterial polysaccharide antigens.
Documented Applications
Preparation of complex multivalent conjugate vaccines against bacterial infections such as meningococcal disease using serogroups A, C, W135, and Y polysaccharides.
Formulation of multivalent pneumococcal conjugate vaccines including serotypes 1, 3, 4, 5, 6B, 7F, 9V, 14, 18C, 19F, and 23F.
Vaccines combining pneumococcal, meningococcal, and Haemophilus influenzae type b polysaccharides for broad protection against bacterial pathogens.
Use of multivalent conjugate vaccines comprising mixtures of different carrier proteins such as tetanus toxoid, bovine thyroglobulin, ovalbumin, and bovine serum albumin to enhance immune responses.
Immunization of subjects including infants, children, and adults to prevent or treat bacterial diseases including meningitis, pneumonia, and other bacterial infections.
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