GBS Polysaccharide-Protein Conjugates for Broad Serotype Coverage
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Solution Overview
Problem
Current polysaccharide-based vaccines for Group B streptococcus (GBS) lack broad coverage against emerging serotypes, particularly serotype IV, and are ineffective in preventing late-onset GBS disease in infants and elderly populations, despite the introduction of screening and antibiotic prophylaxis measures.
Innovation Solution
Development of immunogenic polysaccharide-protein conjugates comprising capsular polysaccharides from GBS with high sialic acid levels, combined with carrier proteins like CRM197, to induce a robust immune response, including conjugates that cover multiple serotypes such as IV, Ia, Ib, II, III, V, VI, VII, VIII, and IX, and methods for their production and administration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If polysaccharide-based vaccines are used for GBS prevention, then immunity is provided against known serotypes, but broad coverage against emerging serotypes including serotype IV is lacking
Solution Approach 1:
The vaccine composition is designed to provide universal protection against multiple GBS serotypes by incorporating polysaccharide-protein conjugates from at least six different serotypes (Ia, Ib, II, III, IV, V, VI, VII, VIII, or IX). This multi-functional approach ensures broad coverage against emerging and established serotypes simultaneously, resolving the contradiction between versatility and reliability.
Solution Approach 2:
The invention uses composite polysaccharide-protein conjugates where capsular polysaccharides from different GBS serotypes are chemically linked to carrier proteins (such as CRM197, tetanus toxoid, or diphtheria toxoid). This composite structure enhances immunogenicity while maintaining broad serotype coverage, addressing both the versatility and reliability requirements.
2Reliability
If conventional polysaccharide vaccines are administered, then some immune response is induced, but the response is insufficient in elderly populations and for late-onset disease prevention
Solution Approach 1:
The invention modifies the chemical and immunological parameters of the vaccine by using polysaccharide-protein conjugates instead of pure polysaccharides. The conjugation process changes the physical-chemical properties and immunogenicity characteristics, producing a stronger and more sustained immune response that is effective in elderly populations and for preventing late-onset disease.
Solution Approach 2:
Carrier proteins serve as intermediaries that bridge the gap between the polysaccharide antigen and the immune system. These protein carriers (CRM197, tetanus toxoid, or diphtheria toxoid) facilitate enhanced antigen presentation and immune recognition, generating robust immune responses in previously under-responsive populations.
3Adaptability or versatility
If multiple serotype conjugates are combined in a single vaccine, then broad coverage is achieved, but manufacturing complexity increases
Solution Approach 1:
The vaccine development process is segmented into modular steps: (1) isolation of capsular polysaccharides from different GBS serotypes, (2) chemical modification and activation of polysaccharides, (3) conjugation to carrier proteins, and (4) formulation of multi-serotype combinations. This segmentation allows each serotype conjugate to be independently optimized and then combined, managing manufacturing complexity while achieving broad coverage.
Solution Approach 2:
Multiple individually optimized polysaccharide-protein conjugates from different serotypes are merged into a single multi-serotype vaccine formulation. This combining approach maintains the immunogenicity benefits of each serotype-specific conjugate while achieving comprehensive protection, balancing versatility with manageable production complexity through standardized conjugation protocols.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The immunogenic conjugates induce a strong immune response, providing broad coverage against GBS serotypes, including emerging strains like IV, and effectively prevent or reduce GBS disease in vulnerable populations, such as infants and the elderly, through enhanced opsonic and bactericidal activities.
Implementation Method 1
reacting isolated GBS capsular polysaccharide with an oxidizing agent, such as periodate
Implementation Method 2
reacting the activated polysaccharide with a carrier protein, such as CRM197, in the presence of a carbodiimide, such as N-ethyl-N'-(3-dimethylaminopropyl)carbodiimide (EDC)
Data Source
AI summary
The invention relates to immunogenic polysaccharide-protein conjugates comprising a capsular polysaccharide (CP) from Streptococcus agalactiae, commonly referred to as group B streptococcus (GBS), and a carrier protein, wherein the CP is selected from the group consisting of serotypes Ia, Ib, II, III, IV, V, VI, VII, VIII, and IX, and wherein the CP has a sialic acid level of greater than about 60%. The invention also relates to methods of making the conjugates and immunogenic compositions comprising the conjugates. The invention also relates to immunogenic compositions comprising polysaccharide-protein conjugates, wherein the conjugates comprise a CP from GBS serotype IV and at least one additional serotype. The invention further relates to methods for inducing an immune response in subjects against GBS and/or for reducing or preventing invasive GBS disease in subjects using the compositions disclosed herein. The resulting antibodies can be used to treat or prevent GBS infection via passive immunotherapy.