eTEC Spacer Glycoconjugates for Stable Saccharide–Protein Coupling
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Solution Overview
Problem
Existing methods for conjugating saccharides to carrier proteins using cross-linking or coupling reagents introduce reactive sites that can adversely affect the functionality and stability of the conjugates, particularly when the carrier molecule is large and complex, posing risks of adverse events in immunization.
Innovation Solution
The use of a bivalent heterobifunctional linker, (2-((2-oxoethyl)thio)ethyl)carbamate (eTEC) spacer, forms stable thioether and amide bonds between saccharides and carrier proteins, minimizing disruptive chemical reactions and preserving the carrier's functionality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If cross-linking or coupling reagents are used to conjugate saccharides to carrier proteins, then conjugation is achieved, but reactive sites are introduced that can adversely affect functionality and stability
Solution Approach 1:
The patent employs a heterobifunctional spacer arm as an intermediary molecule between the saccharide and carrier protein. This spacer contains two different reactive groups: one that reacts with the saccharide and another that reacts with the carrier protein. The spacer mediates the conjugation process while isolating the reactive sites from the final conjugate structure, thus achieving stable conjugation without introducing harmful reactive sites into the functional regions.
Solution Approach 2:
The patent extracts the reactive coupling functionality into a separate spacer molecule rather than using cross-linking reagents that leave reactive sites on the conjugate. The reactive groups are confined to the spacer arm, which is subsequently cleaved or becomes part of a stable linkage, removing the problematic reactive sites from the final immunogenic conjugate while preserving the conjugation capability.
2Ease of manufacture
If reactive sites are introduced into the carrier molecule to create conjugates, then conjugation is achieved, but the larger and more complex carrier molecule becomes more vulnerable to disruptive chemical treatment
Solution Approach 1:
The heterobifunctional spacer acts as a protective intermediary that shields the complex carrier protein from direct exposure to harsh chemical coupling conditions. The spacer's reactive groups are designed to react under mild conditions, and the spacer structure itself protects the carrier protein's functional regions from chemical modification, reducing vulnerability to disruptive treatment.
Solution Approach 2:
The patent applies local quality by concentrating the chemical reactivity exclusively in the spacer arm rather than throughout the entire carrier molecule. The heterobifunctional spacer has specific reactive groups positioned to react only at designated sites, leaving the rest of the carrier protein's functional regions unchanged and protected from chemical disruption.
3Object-affected harmful factors
If excess reactive sites are capped to inactivate them, then safety is improved, but the functionality of the conjugates may be disrupted
Solution Approach 1:
The heterobifunctional spacer serves as a controlled intermediary that limits reactive site exposure. Only the spacer's terminal groups are reactive, and these are precisely positioned and limited in number. The spacer structure ensures that capping or deactivation affects only the spacer itself, not the functional regions of the saccharide-carrier conjugate, thus maintaining functionality while ensuring safety.
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 eTEC spacer-based glycoconjugates provide stable and effective immunogenic compositions that elicit a desired immune response while reducing the risk of adverse events, making them suitable for immunization against pathogenic bacteria like S. pneumonia and N. meningitidis.
Implementation Method 1
The eTEC spacer includes seven linear atoms (i.e., —C(O)NH(CH2)2SCH2C(O)—) and provides stable thioether and amide bonds between the saccharide and carrier protein
Implementation Method 2
The eTEC spacer includes seven linear atoms (i.e., —C(O)NH(CH2)2SCH2C(O)—) and provides stable thioether and amide bonds between the saccharide and carrier protein
Data Source
AI summary
The invention provides eTEC linked glycoconjugates comprising a saccharide covalently conjugated to a carrier protein through a (2-((2-oxoethyl)thio)ethyl)carbamate (eTEC) spacer, immunogenic compositions comprising such glycoconjugates, and methods for the preparation and use of such glycoconjugates and immunogenic compositions.