We provide definitive quantification and structural identification of HMWs, such as non-covalent and covalent aggregates. Aggregates are primary drivers of unwanted immune responses, and their accurate characterization is essential for minimizing patient risk.
Size Variant Analysis Service
Creative Biolabs offers an indispensable solution for ensuring your therapeutic antibody or complex protein meets all critical quality attributes (CQAs) related to structural homogeneity, stability, and patient safety. Our service moves beyond simple retention time quantification to provide the absolute molecular identity and structure-function relationship for every high molecular weight (HMW) and low molecular weight (LMW) species identified. By precisely characterizing these variants, we mitigate the risk of reduced efficacy or potential immunogenicity, delivering the definitive data needed for robust regulatory submissions.
Background What We Can Offer Workflow Why Choose Us FAQs Customer Review Related Services Contact Us
Introduction of Size Variants Analysis
Antibodies are a new class of biological agents that are of increasing interest in immunotherapy applications for tumors. In the construction of antibody formats of different functions, cysteine residues are designed in the heavy and light chain regions of single-chain variable fragments (scFv) to form intrachain disulfide bonds to improve biochemical stability. Structural characterization studies have shown that different size of variants is produced by engineered disulfide bonds on scFv, thereby finding that engineered disulfides are open or due to cysteine or glutathionylation, it do not form an intrachain disulfide bond. In addition, scFv engineered cysteines also form intermolecular disulfide bonds, resulting in the formation of highly stable dimers and aggregates.
Services and Techniques for Size Variants Analysis
Specific Solutions and Deliverables:
Immunogenicity Risk Mitigation
Potency Assurance
Our analysis pinpoints subtle LMWs, including critical fragments (e.g., Fab or Fc cleavage) and truncated forms, which compromise target binding affinity and biological potency, providing the necessary data for upstream process optimization.
Process Robustness Validation
The comprehensive data from our size variants analysis informs formulation design and manufacturing process controls, allowing Creative Biolabs' clients to proactively adjust conditions to minimize future degradation and aggregation.
To understand why the variant exists—a crucial step for process optimization—we employ techniques that probe covalent, structural, and charge differences:
| Variant Type | Technique | Purpose |
|---|---|---|
| Size & Purity Confirmation |
Capillary Electrophoresis-SDS (CE-SDS) |
Orthogonal quantification of size and purity under non-reduced and reduced conditions. |
|
Charge Heterogeneity |
Charge Heterogeneity Capillary Isoelectric Focusing (CIEF) or CEX-HPLC |
Separates and quantifies charge variants based on pI/charge, confirming results from CEX-HPLC. |
| Covalent Size Heterogeneity |
Non-Reduced Capillary SDS (nrcSDS) or Denatured SEC (dSEC) |
Determines the proportion of species held together by covalent bonds (e.g., disulfide cross-links). |
| Secondary Structure |
Fourier Transform Infrared (FTIR) Spectroscopy and Circular Dichroism (CD) |
Provides essential confirmation that the secondary structure (e.g., alpha-helix, beta-sheet content) of the purified monomer remains uncompromised. |
To discuss your specific aggregation or fragmentation challenge, Discover How We Can Help - Request a Consultation today.
Workflow: Precision in Biologic Size Variant Characterization
Our size variants analysis process is a robust, multi-stage workflow designed for clarity, efficiency, and high-fidelity results, ensuring comprehensive data acquisition suitable for regulatory submission.
Why Choose Creative Biolabs?
Creative Biolabs excels at characterizing low-level size variants, ensuring absolute structural certainty in size analysis. Our key advantage is the integrated orthogonal platform, which uniquely combines SEC separation with absolute mass determination (SEC-MALS-RI) and gold-standard verification by SV-AUC in a streamlined workflow, minimizing ambiguity and ensuring regulatory confidence. We provide deep characterization of aggregation mechanisms by using techniques like nrcSDS to distinguish between non-covalent and covalently linked aggregates, offering vital insight for process correction. Our expert team ensures data is translated into actionable insights for process and formulation optimization.
Experience the Creative Biolabs Advantage - Get a Quote Today and secure the structural integrity of your biotherapeutic.
FAQs
What is the main advantage of using SEC-MALS over standard SEC-UV for size variant analysis?
SEC-MALS provides the absolute molecular weight of the eluted species, regardless of its shape or column interaction. This is critical for definitively confirming the stoichiometry of dimers, trimers, and fragments, eliminating ambiguity in your structural characterization.
Can Creative Biolabs characterize non-covalent aggregates, or only those linked by covalent bonds?
Yes, we characterize both types extensively. Non-covalent aggregates are readily measured by our native-state techniques like SEC-MALS and SV-AUC. For covalently linked aggregates, we use orthogonal techniques like nrcSDS to provide precise quantification of these more stable impurities.
If I see a new fragment on my SEC data after a stability test, how can your size variants analysis service help me determine the cleavage site?
We would first isolate that specific LMW fragment using semi-preparative SEC. We then employ high-resolution MS to perform a bottom-up analysis of the isolated fragment. This allows us to pinpoint the exact bond cleavage site.
Customer Review
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Accurate Stoichiometry
The side-by-side CE-SDS and SEC-MALS data allowed us to confidently distinguish between non-covalent dimers and covalently linked aggregates, a clarity that our previous in-house methods lacked. This led to a substantial improvement in our final formulation stability. – J*** S**** -
Absolute Weight Verification
Creative Biolabs' expertise in SEC-MALS was invaluable for our novel scaffold protein. They not only confirmed the monomer's purity but also precisely verified the absolute molecular weight of our desired monomeric species, which was crucial for validating our expression system. – T*** L****
Related Services
Creative Biolabs offers a full suite of services complementary to size variants analysis to ensure your product's success and regulatory compliance.
Antibody Engineering Services
Antibody engineering precisely modifies antibodies to enhance therapeutic potential, addressing immunogenicity, suboptimal binding, and novel function. Creative Biolabs provides a series of antibody engineering services.
Learn More →Therapeutic Developability Assessment Service
Creative Biolabs specializes in therapeutic developability assessment to de-risk biologics pipelines early. By screening for consistent manufacturability, low heterogeneity, and stability, we reduce costs and shorten the overall research timeline.
Learn More →Contact Us
Creative Biolabs' size variants analysis is your guarantee of structural integrity and regulatory compliance. By leveraging our integrated orthogonal platform, we transform complex size heterogeneity data into actionable insights, ensuring your therapeutic asset is safe, stable, and highly potent.
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