Affinity Purification Combined with Vazyme ELISA Sets New Benchmark for dsRNA Control in mRNA Manufacturing
核心洞察
Clark et al. demonstrated that a dsRNA (搜索)-specific affinity resin reduces dsRNA impurities by over 100-fold, reaching levels as low as ~0.00007% w/w while preserving mRNA integrity.
Optimized IVT protocols combined with affinity purification eliminated immunogenicity entirely, with interferon levels indistinguishable from negative controls in A549-cell assays.
Vazyme (搜索)'s EasyAna dsRNA (搜索) ELISA Kit enabled precise trace-level quantification with a detection limit below 10 pg/mL, distinguishing protocol differences that traditional dot blots would miss.
In June 2025, Clark et al. from Repligen (搜索) and etherna (搜索) published findings in Molecular Therapy: Nucleic Acids demonstrating that a dsRNA (搜索)-specific affinity chromatography method can reduce double-stranded RNA byproducts by over 100-fold, reaching levels as low as approximately 0.00007% w/w, while maintaining full mRNA integrity. This advance addresses a critical manufacturing bottleneck for mRNA vaccines and therapeutics, where immunogenic dsRNA impurities have long complicated both efficacy and regulatory approval.
Why dsRNA (搜索) Poses a Persistent Challenge
Double-stranded RNA is a major immunogenic impurity generated during in vitro transcription (IVT) of single-stranded mRNA. It can trigger innate immune responses, including interferon pathway activation, which undermines therapeutic efficacy and raises safety concerns. Removing dsRNA (搜索) is particularly difficult because these byproducts share size, sequence, and charge characteristics with the desired single-stranded mRNA product. Even residual dsRNA levels as low as 0.1% can activate interferon pathways, underscoring the need for both ultra-sensitive detection and highly efficient removal strategies.
Affinity Purification Outperforms Traditional Methods
In side-by-side comparisons, Clark et al. found that the dsRNA (搜索)-specific affinity resin (AVIPure (搜索)) removed dsRNA by approximately 270-fold, driving residual levels down to roughly 0.0003% of total RNA. By contrast, cellulose-based chromatography reduced dsRNA by only approximately 13-fold, and reverse-phase HPLC achieved approximately 58-fold reduction. This means that even after HPLC or ethanol-cellulose purification, trace immunogenic dsRNAs can persist, posing ongoing manufacturing and regulatory risks.
When optimized IVT protocols were combined with affinity purification, dsRNA (搜索) levels reached the remarkably low benchmark of approximately 0.00007% w/w. The optimized IVT protocol alone—using wild-type T7 enzyme with tweaked conditions—yielded approximately 6-fold less dsRNA (0.016% vs. 0.09% w/w) compared to standard IVT before resin treatment. After affinity purification, both routes reached the ~10⁻⁴% dsRNA range, with standard IVT achieving 0.0006% and optimized IVT reaching 0.00007%.
Biological Impact: Eliminating Immunogenicity
In A549-cell reporter assays, standard IVT mRNA triggered approximately 100-fold luciferase induction, whereas affinity-purified mRNA reduced interferon signaling to just 30–50% at 24 and 48 hours. Most notably, optimized IVT combined with affinity purification produced interferon levels indistinguishable from negative controls, fully eliminating immunogenicity. Concurrently, GFP expression peaked in samples with the lowest interferon signal, and only the optimized and purified RNA sustained enhanced GFP activity at 48 hours, correlating lower immunogenicity with increased efficacy and reduced toxicity.
These results demonstrate that high-purity, standard-nucleotide mRNA can match or exceed the performance of modified-nucleotide variants purified via traditional HPLC or cellulose methods, significantly boosting protein expression and cell viability.
Vazyme (搜索)'s Two-Pronged Solution: Detection and Prevention
Vazyme (搜索)'s mRNA quality control toolkit played a pivotal role in enabling this study. The EasyAna dsRNA (搜索) ELISA Kit (DD3509) features a limit of detection below 10 pg/mL and a limit of quantification of approximately 47 pg/mL, allowing precise quantification of trace dsRNA. The kit employs an M2/M5 antibody pair that specifically recognizes dsRNA ≥40 base pairs, unaffected by mRNA modification or length. The ready-to-use kit completes the assay in four hours and is ICH Q2(R2) validated, with a full validation dossier available to meet regulatory requirements.
On the upstream side, Vazyme (搜索)'s T7 Turbo RNA Polymerase (GMP4120) and T7 Low-dsRNA (搜索) RNA Polymerase (DD4126/D13) cut dsRNA formation by approximately 100-fold versus wild-type T7, leaving residual dsRNA at only a few parts per million while maintaining high mRNA yield and integrity. These GMP-grade enzymes support clinical pipelines, including FDA submissions.
Together, these tools form a complete solution: upstream enzyme engineering to suppress dsRNA (搜索) formation, and downstream precision detection to monitor and validate its removal. As Dr. Clark and Dr. Ranaghan (Refeyn (搜索)) discussed in a joint webinar, complementary analytical approaches such as mass photometry can further profile trace dsRNA impurities by leveraging the J2 antibody to identify antibody/dsRNA complexes by their distinct molecular weight profiles, providing an orthogonal characterization method alongside ELISA.
The study establishes a new benchmark for RNA purity in mRNA manufacturing, demonstrating that quantitative dsRNA (搜索) ELISA readouts can distinguish enzyme and protocol differences that traditional dot blot methods would miss, and that combining IVT optimization with affinity chromatography yields mRNA products with immunogenicity profiles indistinguishable from negative controls.