Journal: bioRxiv

Article Title: 3’ UTR Insertion of a Directed-Evolved RNA Element for Enhanced Translation

doi: 10.64898/2026.05.07.723449

Figure Lengend Snippet: (A), Schematic of P51 elements inserted at five sites in the CMV-EGFP reporter 3’UTR. (B), The results of P51 elements inserted at five sites in the CMV-EGFP reporter 3’UTR (Moderna mRNA-1273 3’ UTR) was evaluated by fluorescence spectroscopy in HEK293T cells transfected with the respective engineered plasmids. Scale bar = 1000 µm. (C), Measurement of EGFP fluorescence enhancement mediated by P51 elements inserted at five sites in the CMV-EGFP reporter 3’UTR (Moderna mRNA-1273 3’UTR). Data are normalized to the CMV-EGFP reporter 3’UTR lacking P51 insertions (Ctrl) and presented as mean ± SEM (n = 3). **P < 0.01, two-tailed Student’s t-test. (D), Structures of the P51 element and its four truncations. RNA secondary structures were predicted using the RNAfold WebServer. (E), Schematic of P51 element and its four truncations inserted in the CMV-EGFP reporter 3’UTR. (F), The results of P51 element and its four truncations inserted in the CMV-EGFP reporter 3’UTR (Moderna mRNA-1273 3’UTR) was evaluated by fluorescence spectroscopy in HEK293T cells transfected with the respective engineered plasmids. Scale bar = 1000 µm. (G), Measurement of EGFP fluorescence enhancement mediated by P51 element and its four truncations inserted in the CMV-EGFP reporter 3’UTR (Moderna mRNA-1273 3’UTR). Data are normalized to the CMV-EGFP reporter 3’UTR lacking P51 or P51-truncation insertions (Ctrl) and presented as mean ± SEM (n = 3). ***P < 0.001, ****P < 0.0001, two-tailed Student’s t-test. (H), Schematic diagram of inserting the P51 element or its truncated forms into the pCAG 3’UTR. There were 121 bases between the insertion site and polyA. After transcription, through the mRNA closed-loop translation model, P51 or its truncated forms was spatially close to the 5’ region of mRNA. Data are normalized to the reporter 3’UTR lacking P51 or its truncated forms insertions (Ctrl). (I), P51t2 and P51t3 further enhanced the translation of EGFP in C2C12. Scale bar = 1000 µm. (J), P51t2 and P51t3 further enhanced the translation of Fluc in C2C12.The results of the dual-luciferase reporter system from the C2C12 cells transfected with the plasmid at 48h post transfection. Data are presented as mean ±SEM n = 4. Two-tailed Student’s t-test. ***P < 0.001, ****P < 0.0001. (K), P51t2 and P51t3 further enhanced the translation of uDys in C2C12. Western blot data from the C2C12 cells transfected with the plasmid at 48h post transfection. (L), Quantitative heat map of the experiment of figure (k). n=5. (M), The RT-qPCR results of uDys mRNA. Data are presented as mean ±SEM n = 4. Two-tailed Student’s t-test. ns, not significant.

Article Snippet: In clinically relevant models, insertion of P51t3 into an mRNA containing Moderna mRNA-1273 UTRs increased spike protein expression 2–3-fold in C2C12 cells ( ).48 Similarly, in constructs mimicking BioNTech BNT162b2 UTRs, P51t3 boosted Fluc translation nearly 2-fold ( ).

Techniques: Fluorescence, Spectroscopy, Transfection, Two Tailed Test, Luciferase, Plasmid Preparation, Western Blot, Quantitative RT-PCR

Journal: bioRxiv

Article Title: 3’ UTR Insertion of a Directed-Evolved RNA Element for Enhanced Translation

doi: 10.64898/2026.05.07.723449

Figure Lengend Snippet: (A), Schematic of P51 elements inserted at five sites in the CMV-Fluc reporter 3’UTR. (B), The results of P51 elements inserted at five sites in the CMV-Fluc reporter 3’UTR (Moderna mRNA-1273 3’UTR) was evaluated by dual-luciferase assay in HEK293T cells transfected with the respective engineered plasmids. Data are normalized to the CMV-Fluc reporter 3’ UTR lacking P51 insertions (Ctrl) and presented as mean ± SEM (n = 3). ****P < 0.0001, two-tailed Student’s t-test. (C), Schematic of P51 element and its four truncations inserted in the CMV-Fluc reporter 3’UTR. (D), The results of P51 element and its four truncations inserted in the CMV-Fluc reporter 3’UTR (Moderna mRNA-1273 3’UTR) was evaluated by dual-luciferase assay in HEK293T cells transfected with the respective engineered plasmids. Data are normalized to the CMV-Fluc reporter 3’UTR lacking P51 or P51-truncation insertions (Ctrl) and presented as mean ± SEM (n = 3). **P < 0.01,***P < 0.001, two-tailed Student’s t-test. (E), P51t3 is inserted at different sites of B2M 3’UTR. (F), P51t3 enhanced the translation of Fluc (B2M 3’UTR) in HEK293T. The results of the dual-luciferase reporter system from the HEK293T cells transfected with the plasmid at 48h post transfection. Data are normalized to the reporter 3’UTR lacking P51t3 insertions (Ctrl) and presented as mean ±SEM n = 5. Two-tailed Student’s t-test. **P < 0.01, ****P < 0.0001. (G), P51t3 is inserted at different sites of TMSB10 3’UTR. (H), P51t3 enhanced the translation of Fluc (TMSB10 3’UTR) in HEK293T. The results of the dual-luciferase reporter system from the HEK293T cells transfected with the plasmid at 48h post transfection. Data are normalized to the reporter 3’UTR lacking P51t3 insertions (Ctrl) and presented as mean ±SEM n = 5. Two-tailed Student’s t-test. *P < 0.05, **P < 0.01, ****P < 0.0001.

Article Snippet: In clinically relevant models, insertion of P51t3 into an mRNA containing Moderna mRNA-1273 UTRs increased spike protein expression 2–3-fold in C2C12 cells ( ).48 Similarly, in constructs mimicking BioNTech BNT162b2 UTRs, P51t3 boosted Fluc translation nearly 2-fold ( ).

Techniques: Luciferase, Transfection, Two Tailed Test, Plasmid Preparation

Journal: bioRxiv

Article Title: 3’ UTR Insertion of a Directed-Evolved RNA Element for Enhanced Translation

doi: 10.64898/2026.05.07.723449

Figure Lengend Snippet: (A), Structures of the P51 element and its truncations P51t2 and P51t3. Blue circles denote evolutionary sites; gray circles indicate potential MRE sites. RNA secondary structures were predicted using RNAfold WebServer and rendered using RNAcanvas. (B), Predicted MRE landscape of the Moderna mRNA-1273 3’UTR Site2 upon insertion of P51 or its truncations. Target scores are displayed as heat maps. MRE analysis was performed using miRDB. (C), Predicted MRE landscape of the pCAG 3’UTR L1 upon insertion of SINEB2 element or P51 element or P51-truncations. Target scores are displayed as heat maps. MRE analysis was performed using miRDB. (D), Predicted MRE landscape of the Moderna mRNA-1273 3’UTR Site3 upon insertion of P51 or its truncations. Target scores are displayed as heat maps. MRE analysis was performed using miRDB.

Article Snippet: In clinically relevant models, insertion of P51t3 into an mRNA containing Moderna mRNA-1273 UTRs increased spike protein expression 2–3-fold in C2C12 cells ( ).48 Similarly, in constructs mimicking BioNTech BNT162b2 UTRs, P51t3 boosted Fluc translation nearly 2-fold ( ).

Techniques:

Journal: bioRxiv

Article Title: 3’ UTR Insertion of a Directed-Evolved RNA Element for Enhanced Translation

doi: 10.64898/2026.05.07.723449

Figure Lengend Snippet: (A), Schematic of P51 element inserted at three sites within the 3’UTR of IVT mRNA. (B), The results of P51 element inserted at three sites within the 3’UTR of IVT mRNA was evaluated by dual-luciferase assay in HEK293T cells transfected with the respective mRNAs. Data are normalized to the IVT mRNA 3’UTR lacking P51 insertions (Ctrl) and presented as mean ± SEM (n = 3). **P < 0.01, ****P < 0.0001, two-tailed Student’s t-test. (C), Schematic of P51 element or its truncations inserted at Site2 and Site3 within the 3’UTR of IVT mRNA. (D), The results of P51 element or its truncations inserted at Site2 and Site3 within the 3’UTR of IVT mRNA was evaluated by dual-luciferase assay in HEK293T cells transfected with the respective mRNAs. Data are normalized to the IVT mRNA 3’UTR lacking P51 insertions (Ctrl) and presented as mean ± SEM (n = 3). (E), The results of P51t3 element inserted at Site3 within the 3’UTR of IVT mRNA was evaluated by dual-luciferase assay in C2C12 and HEK293T cells transfected with 50 ng (gray) or 100 ng (blue) of the respective mRNAs. Data are normalized to the IVT mRNA 3’UTR lacking P51t3 insertions (Ctrl) and presented as mean ± SEM (n = 3). ***P < 0.001, ****P < 0.0001, two-tailed Student’s t-test. (F), Schematic of P51 elements inserted at three sites within the 3’UTR (Moderna mRNA-1273 3’UTR) of IVT EGFP mRNA. (G), (H), The results of P51 elements inserted at three sites within the 3’UTR (Moderna mRNA-1273 3’UTR) of IVT EGFP mRNA was evaluated by fluorescence spectroscopy in HEK293T cells transfected with the respective mRNAs. Scale bar = 1000 µm. EGFP data are normalized to the IVT mRNA 3’UTR lacking P51t3 insertions (Ctrl) and presented as mean ± SEM (n = 3). ****P < 0.0001, two-tailed Student’s t-test. (I), Schematic of P51t3 element inserted at Site3 within the 3’UTR of IVT Moderna mRNA-1273. (J), The results of P51t3 element inserted at Site3 within the 3’UTR of IVT Moderna mRNA-1273 was evaluated by western blot assay in HEK293T cells transfected with the mRNAs. Data are normalized to the IVT mRNA 3’UTR lacking P51t3 insertions (Ctrl) and presented as mean ± SEM (n = 3). **P < 0.01, two-tailed Student’s t-test. (K), Schematic of P51t3 elements inserted at four sites within the 3’UTR (BioNTech/Pfizer BNT-162b2 3’UTR) of IVT Fluc mRNA. (L), The results of P51t3 elements inserted at four sites within the 3’UTR (BioNTech/Pfizer BNT-162b2 3’UTR) of IVT Fluc mRNA was evaluated by dual-luciferase assay in HEK293T cells transfected with the respective mRNAs. Data are normalized to the IVT mRNA 3’UTR lacking P51t3 insertions (Ctrl) and presented as mean ± SEM (n = 3). ****P < 0.0001, two-tailed Student’s t-test. (M), Schematic of in vivo luminescence quantification. Fluc mRNAs were formulated in LNPs and equal molar quantities of mRNA-LNP complexes were administered through IM injection to male 6-8 weeks C57BL/6J mice. (N), (O), Exemplary in vivo luminescence images of mice treated with Fluc mRNA at 4, 24 and 48 h post mRNA–LNP complex administration. Color scale of the heatmaps, radiance (photons s−1 cm−2 sr−1). Luminescence was measured by integration of total flux for each mouse. Data are normalized to the mice of Ctrl group (IVT mRNA 3’UTR lacking P51t3 insertions-LNP-treated) and presented as mean ± SEM (n = 3). *P < 0.05, **P < 0.01, two-tailed Student’s t-test.

Article Snippet: In clinically relevant models, insertion of P51t3 into an mRNA containing Moderna mRNA-1273 UTRs increased spike protein expression 2–3-fold in C2C12 cells ( ).48 Similarly, in constructs mimicking BioNTech BNT162b2 UTRs, P51t3 boosted Fluc translation nearly 2-fold ( ).

Techniques: Luciferase, Transfection, Two Tailed Test, Fluorescence, Spectroscopy, Western Blot, In Vivo, Injection

Journal: Frontiers in Immunology

Article Title: Profiling of SARS-CoV-2 virus shedding, antibody neutralization, and T-cell receptor repertoires in a large, multi-center cohort of young adults with varied prior exposures

doi: 10.3389/fimmu.2026.1731974

Figure Lengend Snippet: Spike- and non-spike-reactive T cell receptor beta-chain (TRB) sequences by exposure category. (A) T cell breadth (defined as the proportion of unique TCRs matching the database of public SARS-CoV-2 Spike and non-spike sequences) stratified by exposure status. Statistical significance was determined using a two-sided Wilcoxon rank sum test. (B) Longitudinal T cell breadth in unvaccinated participants before and after confirmed SARS-CoV-2 infection. Gray lines connect samples from the same participant. (C) T cell response breadth for seronegative (SN, black) and seropositive (SP, cyan) individuals at intervals relative to the second mRNA vaccine dose. Significance was calculated using a two-sided Wilcoxon rank sum test. (D) Longitudinal T cell breadth in seropositive and seronegative participants before and after a two-dose mRNA vaccination series. Gray lines connect samples from the same participant. (E) Scatter plot of clonal frequencies pre- versus post-infection in a representative participant. Colored points indicate significantly expanded (red) and contracted (brown) clones (fold change > 4; FDR < 0.05). Analysis is restricted to clones with ≥5 copies at either timepoint. A slight jitter was applied to minimize overplotting. (F) Longitudinal trajectories of the expanded and contracted clones identified in (E) . (G–I) Number of expanded clones per participant following vaccination in seronegative individuals (G) , following infection (H) , and following vaccination in seropositive individuals (I) . Gray bars indicate the number of contracted clones. (J) Number of expanded clones stratified by exposure status. Significance was determined by two-sided Wilcoxon rank sum tests (*** P < 0.001, ** P < 0.01, * P < 0.05; ns, not significant).

Article Snippet: We analyzed immunological responses to two doses of mRNA SARS-CoV-2 spike vaccination (Moderna mRNA-1273) and/or SARS-CoV-2 infection in 209 participants (77 male and 132 female participants) ranging in age from 18 to 29 years old (median 21).

Techniques: Infection, Clone Assay

Journal: Frontiers in Immunology

Article Title: Profiling of SARS-CoV-2 virus shedding, antibody neutralization, and T-cell receptor repertoires in a large, multi-center cohort of young adults with varied prior exposures

doi: 10.3389/fimmu.2026.1731974

Figure Lengend Snippet: Samples were categorized relative to SARS-CoV-2 exposure events. (A) Schematic of sample categorization by timing from last exposure. (B) Days since last exposure by category. See Methods for sample stratification criteria.

Article Snippet: We analyzed immunological responses to two doses of mRNA SARS-CoV-2 spike vaccination (Moderna mRNA-1273) and/or SARS-CoV-2 infection in 209 participants (77 male and 132 female participants) ranging in age from 18 to 29 years old (median 21).

Techniques:

Journal: Cell Biomaterials

Article Title: A hybrid polymeric system for pulmonary mRNA delivery: Advancing mucosal vaccine development

doi: 10.1016/j.celbio.2025.100311

Figure Lengend Snippet: Coculture of transfected BMDCs and CD8 + T cells from OT-1 mice (A) Isolation of CD8 + T cells from OT-1 mouse splenocytes using magnetic-activated cell sorting (MACS). (B) Percentages of CD8 + T cells before and after isolation. (C) Percentages of IFN- γ -secreting CD8 + T cells after 6 h of coculture with transfected BMDCs. (D) IFN- γ concentrations in the cell culture medium after 3 days of co-culture. (E) CD8 + T cell proliferation assessed using carboxyfluorescein succinimidyl ester (CFSE) staining, expressed as the percentage of divided cell subsets. (F) Schematic diagram illustrating antigen-specific recognition between DCs and CD8 + T cells from OT-1 mice. (G) Percentages of IFN- γ -secreting CD8 + T cells. (H) IFN- γ concentrations in the cell culture medium. (I) CD8 + T cell proliferation after coculture with BMDCs pretreated with empty PLGA/PBAE nanoparticles, nanoparticles loaded with OVA mRNA, or SARS-CoV-2 spike protein mRNA. Data are presented as mean ± SD, n = 3. ✽ p < 0.05, ✽✽ p < 0.01, ✽✽✽ p < 0.001, ✽✽✽✽ p < 0.0001; ns, not significant; one-way ANOVA.

Article Snippet: SARS-CoV-2 spike protein mRNA was provided by Daiichi Sankyo Europe (Munich, Germany).

Techniques: Transfection, Isolation, FACS, Cell Culture, Co-Culture Assay, Staining

Journal: medRxiv

Article Title: In Vivo Blood Kinetics and Transcript Integrity of Three mRNA–Lipid Nanoparticle Vaccines in Humans

doi: 10.64898/2026.03.13.26348310

Figure Lengend Snippet: A) Three cohort of human subjects were recruited who received either Moderna, Pfizer, or mRNA-RBD vaccination. B) Serial blood samples were collected before and after vaccination and analyzed by ddPCR, mass spectrometry and ELISA to quantify vaccine mRNA, ionizable lipid, and antibody response (anti-PEG and anti-spike), respectively.

Article Snippet: Across early post-vaccination samples, the fraction of intact spike mRNA was broadly similar between Moderna and Pfizer, generally ∼10–25% of total vaccine mRNA detected ( ).

Techniques: Mass Spectrometry, Enzyme-linked Immunosorbent Assay

Journal: medRxiv

Article Title: In Vivo Blood Kinetics and Transcript Integrity of Three mRNA–Lipid Nanoparticle Vaccines in Humans

doi: 10.64898/2026.03.13.26348310

Figure Lengend Snippet: Comparison of in vivo vaccine mRNA kinetics in human blood following three types of SARS-CoV-2 mRNA vaccination (Moderna, Pfizer, or mRNA-RBD). (A–C) Longitudinal vaccine mRNA concentrations (copies µL −1 ) in human blood from seven cohorts receiving either (A) Moderna bivalent ancestral + BA.1, bivalent ancestral + BA.5, or monovalent XBB.1.5; (B) Pfizer; or (C) mRNA-RBD at 10, 20, or 50 µg doses. The lower limit of quantification (LLOQ; dashed line) was determined from linear standard curves (Figure S1D–G). In panel A, two the lower limits of quantifications (LLOQs) are shown: 0.4 copies µL −1 for Moderna XBB.1.5 (dark blue dashed line) and 0.93 copies µL −1 for Moderna bivalent vaccines (light blue dashed line). Undetected samples (0 copies μL −1 ) were plotted with open symbols. (D–G) Comparison of (D) mRNA concentration at day 6–7 post-vaccination, (E) post-peak mRNA decay rates, (F) post-peak area under the curve (AUC) of mRNA kinetics in blood, and (G) averaged mRNA kinetics across donors among the three vaccine types. In (D–F), each dot represents one participant, and the horizontal line indicates the median. In (G), averaged mRNA kinetics are shown as mean predictions from the best-fit linear model, with shaded regions indicating the 95% confidence interval bounds. Statistical analysis was performed using the nonparametric Kruskal–Wallis test with Dunn’s multiple comparisons in (D, F) and the likelihood ratio test in (E).

Article Snippet: Across early post-vaccination samples, the fraction of intact spike mRNA was broadly similar between Moderna and Pfizer, generally ∼10–25% of total vaccine mRNA detected ( ).

Techniques: Comparison, In Vivo, Vaccines, Concentration Assay

Journal: medRxiv

Article Title: In Vivo Blood Kinetics and Transcript Integrity of Three mRNA–Lipid Nanoparticle Vaccines in Humans

doi: 10.64898/2026.03.13.26348310

Figure Lengend Snippet: Comparison of in vivo ionizable lipid kinetics in human blood following Moderna, Pfizer, or mRNA-RBD vaccination. (A–C) Longitudinal ionizable lipid concentrations (ng mL −1 ) in human blood from seven cohorts who received either (A) Moderna bivalent ancestral + BA.1, bivalent ancestral + BA.5, or monovalent XBB.1.5 (formulated with SM-102); (B) Pfizer (formulated with ALC-0315); or (C) mRNA-RBD (formulated with Dlin-MC3-DMA) vaccination at 10, 20, or 50 µg doses. (D–G) Comparison of (D) ionizable lipid concentration at day 6–7 post-vaccination, (E) post-peak ionizable lipid decay rates, (F) post-peak AUC of ionizable lipid kinetics in blood, and (G) averaged ionizable lipid kinetics across donors among the three vaccine types. In (D–F), each dot represents one participant, and the horizontal line indicates the median. In (G), averaged ionizable lipid kinetics are shown as mean predictions from the best-fit linear model, with shaded regions indicating the 95% confidence interval bounds. Statistical analysis was performed using the nonparametric Kruskal–Wallis test with Dunn’s multiple comparisons in (D, F) and the likelihood ratio test in (E).

Article Snippet: Across early post-vaccination samples, the fraction of intact spike mRNA was broadly similar between Moderna and Pfizer, generally ∼10–25% of total vaccine mRNA detected ( ).

Techniques: Comparison, In Vivo, Concentration Assay

Journal: medRxiv

Article Title: In Vivo Blood Kinetics and Transcript Integrity of Three mRNA–Lipid Nanoparticle Vaccines in Humans

doi: 10.64898/2026.03.13.26348310

Figure Lengend Snippet: Comparison of in vivo vaccine mRNA integrity in human blood between Moderna and Pfizer vaccines. (A,B) Longitudinal vaccine mRNA integrity in human blood from four cohorts who received either (A) Moderna bivalent ancestral + BA.1, bivalent ancestral + BA.5, or monovalent XBB.1.5 or (B) Pfizer vaccination. (C,D) Longitudinal intact vaccine mRNA concentration (copies µL −1 ) in human blood from the four cohorts. The LLOQ (shown as a dashed line) was determined based on the linear standard curves of vaccine mRNA (Figure S1D–F). In panel C, two LLOQs are shown: 0.4 copies µL −1 for Moderna XBB.1.5 (dark blue dashed line) and 0.93 copies µL −1 for Moderna bivalent vaccines (light blue dashed line). Undetected samples (0 copies μL −1 ) were plotted with open symbols. (E–G) Comparison of (E) post-peak intact mRNA decay rates, (F) post-peak AUC of intact mRNA kinetics in blood, and (G) averaged intact mRNA kinetics across donors between the two vaccine types. In (E,F), each dot represents one participant, and the horizontal line indicates the median. In (G), averaged intact mRNA kinetics are shown as mean predictions from the best-fit linear model, with shaded regions indicating the 95% confidence interval bounds. Statistical analysis was performed using the nonparametric Mann−Whitney U test in (F) and the likelihood ratio test in (E).

Article Snippet: Across early post-vaccination samples, the fraction of intact spike mRNA was broadly similar between Moderna and Pfizer, generally ∼10–25% of total vaccine mRNA detected ( ).

Techniques: Comparison, In Vivo, Vaccines, Concentration Assay, MANN-WHITNEY

Journal: medRxiv

Article Title: In Vivo Blood Kinetics and Transcript Integrity of Three mRNA–Lipid Nanoparticle Vaccines in Humans

doi: 10.64898/2026.03.13.26348310

Figure Lengend Snippet: Comparison of in vivo decay kinetics of vaccine mRNA and ionizable lipids in human blood following Moderna, Pfizer, or mRNA-RBD vaccination. (A) Best-fit decay slopes of total mRNA, intact mRNA, and ionizable lipids across the three vaccines. The response at the peak time point for each parameter was normalized to 100%, and the percentage change over time illustrates the decline estimated from the best-fit linear model. (B) Half-life of total mRNA, intact mRNA, and ionizable lipids from the three vaccines, shown as the mean with upper and lower bound of 95% confidence intervals calculated across multiple donors in each cohort.

Article Snippet: Across early post-vaccination samples, the fraction of intact spike mRNA was broadly similar between Moderna and Pfizer, generally ∼10–25% of total vaccine mRNA detected ( ).

Techniques: Comparison, In Vivo, Vaccines

Journal: medRxiv

Article Title: In Vivo Blood Kinetics and Transcript Integrity of Three mRNA–Lipid Nanoparticle Vaccines in Humans

doi: 10.64898/2026.03.13.26348310

Figure Lengend Snippet: Comparison of anti-PEG antibody levels in human blood before and after Moderna, Pfizer, or mRNA-RBD vaccination. (A,B) Comparison of plasma anti-PEG IgG and IgM endpoint titers before vaccination (Pre-Vax) and after vaccination (Post-Vax) for the three vaccine types. (C,D) Cross-comparison of fold changes (Post-Vax/Pre-Vax) in anti-PEG IgG and IgM endpoint titers among the three vaccine types. In (C,D), each dot represents one participant, and the horizontal line indicates the mean. Statistical analysis was performed using the nonparametric Wilcoxon matched-pairs signed rank test in (A,B) and the nonparametric Kruskal–Wallis test with Dunn’s multiple comparisons in (C,D).

Article Snippet: Across early post-vaccination samples, the fraction of intact spike mRNA was broadly similar between Moderna and Pfizer, generally ∼10–25% of total vaccine mRNA detected ( ).

Techniques: Comparison, Clinical Proteomics

Journal: medRxiv

Article Title: In Vivo Blood Kinetics and Transcript Integrity of Three mRNA–Lipid Nanoparticle Vaccines in Humans

doi: 10.64898/2026.03.13.26348310

Figure Lengend Snippet: In vivo degradation patterns of Moderna vaccine mRNA in human blood evaluated using ten two-primer fragments in a duplex PCR assay. (A) Schematic illustration of the ten two-primer fragments, each targeting two regions of the Moderna vaccine mRNA sequence in the duplex ddPCR assay to assess degradation patterns of vaccine mRNA. (B) Vaccine mRNA integrity in plasma from six subjects at days 1, 4, and 7 post-Moderna vaccination (three subjects received the bivalent ancestral + BA.1 vaccine and three received the bivalent ancestral + BA.5 vaccine) assessed using the ten fragments. (C) Comparison of mRNA integrity across the ten fragments in plasma samples (day 1 post-vaccination), neat Moderna vaccine, and synthetic Moderna vaccine mRNA. (D,E) Spearman correlation analysis between mRNA integrity in plasma at day 1 post-vaccination and mRNA integrity in (D) neat Moderna vaccine or (E) synthetic Moderna vaccine mRNA. (F,G) Comparison of intact mRNA decay rates across (F) the ten fragments or (G) the six subjects. (H) Best-fit decay slopes of intact mRNA across six donors, with each data point representing the average decay rate calculated from ten individual fragments. For each donor, decay rates were estimated separately for each fragment, and the mean of these ten fragment-specific rates was used to represent the donor-level decay slope. As the decay slopes of donors 2 and 5 overlap, the curve of donor 5 was plotted with higher thickness than that of donor 2 to improve readability. In (C,F), mRNA integrity (%) and decay rates in plasma samples are shown as the mean with upper and lower bound of 95% confidence intervals calculated across six donors.

Article Snippet: Across early post-vaccination samples, the fraction of intact spike mRNA was broadly similar between Moderna and Pfizer, generally ∼10–25% of total vaccine mRNA detected ( ).

Techniques: In Vivo, Sequencing, Clinical Proteomics, Comparison

Journal: medRxiv

Article Title: In Vivo Blood Kinetics and Transcript Integrity of Three mRNA–Lipid Nanoparticle Vaccines in Humans

doi: 10.64898/2026.03.13.26348310

Figure Lengend Snippet: A) Three cohort of human subjects were recruited who received either Moderna, Pfizer, or mRNA-RBD vaccination. B) Serial blood samples were collected before and after vaccination and analyzed by ddPCR, mass spectrometry and ELISA to quantify vaccine mRNA, ionizable lipid, and antibody response (anti-PEG and anti-spike), respectively.

Article Snippet: As a reference, synthetic spike mRNA, synthesized based on the putative Moderna vaccine mRNA sequence, was largely intact across all ten fragments (green triangles in , mean integrity 86.7%, range 82.4–93.7%) and did not show a significant correlation with the fragment-by-fragment profile observed in blood ( ).Together, these data suggest that (i) the pattern of fragment integrity detected in blood at day 1 largely reflects the formulation’s starting integrity profile; (ii) there was minimal further degradation between vaccination and one day post-vaccination, when mRNA–LNPs travel in vivo into the blood; (iii) the integrity loss of vaccine product is biased toward the 3′-proximal regions of the transcript.

Techniques: Mass Spectrometry, Enzyme-linked Immunosorbent Assay

Journal: medRxiv

Article Title: In Vivo Blood Kinetics and Transcript Integrity of Three mRNA–Lipid Nanoparticle Vaccines in Humans

doi: 10.64898/2026.03.13.26348310

Figure Lengend Snippet: Comparison of in vivo vaccine mRNA kinetics in human blood following three types of SARS-CoV-2 mRNA vaccination (Moderna, Pfizer, or mRNA-RBD). (A–C) Longitudinal vaccine mRNA concentrations (copies µL −1 ) in human blood from seven cohorts receiving either (A) Moderna bivalent ancestral + BA.1, bivalent ancestral + BA.5, or monovalent XBB.1.5; (B) Pfizer; or (C) mRNA-RBD at 10, 20, or 50 µg doses. The lower limit of quantification (LLOQ; dashed line) was determined from linear standard curves (Figure S1D–G). In panel A, two the lower limits of quantifications (LLOQs) are shown: 0.4 copies µL −1 for Moderna XBB.1.5 (dark blue dashed line) and 0.93 copies µL −1 for Moderna bivalent vaccines (light blue dashed line). Undetected samples (0 copies μL −1 ) were plotted with open symbols. (D–G) Comparison of (D) mRNA concentration at day 6–7 post-vaccination, (E) post-peak mRNA decay rates, (F) post-peak area under the curve (AUC) of mRNA kinetics in blood, and (G) averaged mRNA kinetics across donors among the three vaccine types. In (D–F), each dot represents one participant, and the horizontal line indicates the median. In (G), averaged mRNA kinetics are shown as mean predictions from the best-fit linear model, with shaded regions indicating the 95% confidence interval bounds. Statistical analysis was performed using the nonparametric Kruskal–Wallis test with Dunn’s multiple comparisons in (D, F) and the likelihood ratio test in (E).

Article Snippet: As a reference, synthetic spike mRNA, synthesized based on the putative Moderna vaccine mRNA sequence, was largely intact across all ten fragments (green triangles in , mean integrity 86.7%, range 82.4–93.7%) and did not show a significant correlation with the fragment-by-fragment profile observed in blood ( ).Together, these data suggest that (i) the pattern of fragment integrity detected in blood at day 1 largely reflects the formulation’s starting integrity profile; (ii) there was minimal further degradation between vaccination and one day post-vaccination, when mRNA–LNPs travel in vivo into the blood; (iii) the integrity loss of vaccine product is biased toward the 3′-proximal regions of the transcript.

Techniques: Comparison, In Vivo, Vaccines, Concentration Assay

Journal: medRxiv

Article Title: In Vivo Blood Kinetics and Transcript Integrity of Three mRNA–Lipid Nanoparticle Vaccines in Humans

doi: 10.64898/2026.03.13.26348310

Figure Lengend Snippet: Comparison of in vivo ionizable lipid kinetics in human blood following Moderna, Pfizer, or mRNA-RBD vaccination. (A–C) Longitudinal ionizable lipid concentrations (ng mL −1 ) in human blood from seven cohorts who received either (A) Moderna bivalent ancestral + BA.1, bivalent ancestral + BA.5, or monovalent XBB.1.5 (formulated with SM-102); (B) Pfizer (formulated with ALC-0315); or (C) mRNA-RBD (formulated with Dlin-MC3-DMA) vaccination at 10, 20, or 50 µg doses. (D–G) Comparison of (D) ionizable lipid concentration at day 6–7 post-vaccination, (E) post-peak ionizable lipid decay rates, (F) post-peak AUC of ionizable lipid kinetics in blood, and (G) averaged ionizable lipid kinetics across donors among the three vaccine types. In (D–F), each dot represents one participant, and the horizontal line indicates the median. In (G), averaged ionizable lipid kinetics are shown as mean predictions from the best-fit linear model, with shaded regions indicating the 95% confidence interval bounds. Statistical analysis was performed using the nonparametric Kruskal–Wallis test with Dunn’s multiple comparisons in (D, F) and the likelihood ratio test in (E).

Article Snippet: As a reference, synthetic spike mRNA, synthesized based on the putative Moderna vaccine mRNA sequence, was largely intact across all ten fragments (green triangles in , mean integrity 86.7%, range 82.4–93.7%) and did not show a significant correlation with the fragment-by-fragment profile observed in blood ( ).Together, these data suggest that (i) the pattern of fragment integrity detected in blood at day 1 largely reflects the formulation’s starting integrity profile; (ii) there was minimal further degradation between vaccination and one day post-vaccination, when mRNA–LNPs travel in vivo into the blood; (iii) the integrity loss of vaccine product is biased toward the 3′-proximal regions of the transcript.

Techniques: Comparison, In Vivo, Concentration Assay

Journal: medRxiv

Article Title: In Vivo Blood Kinetics and Transcript Integrity of Three mRNA–Lipid Nanoparticle Vaccines in Humans

doi: 10.64898/2026.03.13.26348310

Figure Lengend Snippet: Comparison of in vivo vaccine mRNA integrity in human blood between Moderna and Pfizer vaccines. (A,B) Longitudinal vaccine mRNA integrity in human blood from four cohorts who received either (A) Moderna bivalent ancestral + BA.1, bivalent ancestral + BA.5, or monovalent XBB.1.5 or (B) Pfizer vaccination. (C,D) Longitudinal intact vaccine mRNA concentration (copies µL −1 ) in human blood from the four cohorts. The LLOQ (shown as a dashed line) was determined based on the linear standard curves of vaccine mRNA (Figure S1D–F). In panel C, two LLOQs are shown: 0.4 copies µL −1 for Moderna XBB.1.5 (dark blue dashed line) and 0.93 copies µL −1 for Moderna bivalent vaccines (light blue dashed line). Undetected samples (0 copies μL −1 ) were plotted with open symbols. (E–G) Comparison of (E) post-peak intact mRNA decay rates, (F) post-peak AUC of intact mRNA kinetics in blood, and (G) averaged intact mRNA kinetics across donors between the two vaccine types. In (E,F), each dot represents one participant, and the horizontal line indicates the median. In (G), averaged intact mRNA kinetics are shown as mean predictions from the best-fit linear model, with shaded regions indicating the 95% confidence interval bounds. Statistical analysis was performed using the nonparametric Mann−Whitney U test in (F) and the likelihood ratio test in (E).

Article Snippet: As a reference, synthetic spike mRNA, synthesized based on the putative Moderna vaccine mRNA sequence, was largely intact across all ten fragments (green triangles in , mean integrity 86.7%, range 82.4–93.7%) and did not show a significant correlation with the fragment-by-fragment profile observed in blood ( ).Together, these data suggest that (i) the pattern of fragment integrity detected in blood at day 1 largely reflects the formulation’s starting integrity profile; (ii) there was minimal further degradation between vaccination and one day post-vaccination, when mRNA–LNPs travel in vivo into the blood; (iii) the integrity loss of vaccine product is biased toward the 3′-proximal regions of the transcript.

Techniques: Comparison, In Vivo, Vaccines, Concentration Assay, MANN-WHITNEY

Journal: medRxiv

Article Title: In Vivo Blood Kinetics and Transcript Integrity of Three mRNA–Lipid Nanoparticle Vaccines in Humans

doi: 10.64898/2026.03.13.26348310

Figure Lengend Snippet: Comparison of in vivo decay kinetics of vaccine mRNA and ionizable lipids in human blood following Moderna, Pfizer, or mRNA-RBD vaccination. (A) Best-fit decay slopes of total mRNA, intact mRNA, and ionizable lipids across the three vaccines. The response at the peak time point for each parameter was normalized to 100%, and the percentage change over time illustrates the decline estimated from the best-fit linear model. (B) Half-life of total mRNA, intact mRNA, and ionizable lipids from the three vaccines, shown as the mean with upper and lower bound of 95% confidence intervals calculated across multiple donors in each cohort.

Article Snippet: As a reference, synthetic spike mRNA, synthesized based on the putative Moderna vaccine mRNA sequence, was largely intact across all ten fragments (green triangles in , mean integrity 86.7%, range 82.4–93.7%) and did not show a significant correlation with the fragment-by-fragment profile observed in blood ( ).Together, these data suggest that (i) the pattern of fragment integrity detected in blood at day 1 largely reflects the formulation’s starting integrity profile; (ii) there was minimal further degradation between vaccination and one day post-vaccination, when mRNA–LNPs travel in vivo into the blood; (iii) the integrity loss of vaccine product is biased toward the 3′-proximal regions of the transcript.

Techniques: Comparison, In Vivo, Vaccines

Journal: medRxiv

Article Title: In Vivo Blood Kinetics and Transcript Integrity of Three mRNA–Lipid Nanoparticle Vaccines in Humans

doi: 10.64898/2026.03.13.26348310

Figure Lengend Snippet: Comparison of anti-PEG antibody levels in human blood before and after Moderna, Pfizer, or mRNA-RBD vaccination. (A,B) Comparison of plasma anti-PEG IgG and IgM endpoint titers before vaccination (Pre-Vax) and after vaccination (Post-Vax) for the three vaccine types. (C,D) Cross-comparison of fold changes (Post-Vax/Pre-Vax) in anti-PEG IgG and IgM endpoint titers among the three vaccine types. In (C,D), each dot represents one participant, and the horizontal line indicates the mean. Statistical analysis was performed using the nonparametric Wilcoxon matched-pairs signed rank test in (A,B) and the nonparametric Kruskal–Wallis test with Dunn’s multiple comparisons in (C,D).

Article Snippet: As a reference, synthetic spike mRNA, synthesized based on the putative Moderna vaccine mRNA sequence, was largely intact across all ten fragments (green triangles in , mean integrity 86.7%, range 82.4–93.7%) and did not show a significant correlation with the fragment-by-fragment profile observed in blood ( ).Together, these data suggest that (i) the pattern of fragment integrity detected in blood at day 1 largely reflects the formulation’s starting integrity profile; (ii) there was minimal further degradation between vaccination and one day post-vaccination, when mRNA–LNPs travel in vivo into the blood; (iii) the integrity loss of vaccine product is biased toward the 3′-proximal regions of the transcript.

Techniques: Comparison, Clinical Proteomics

Journal: medRxiv

Article Title: In Vivo Blood Kinetics and Transcript Integrity of Three mRNA–Lipid Nanoparticle Vaccines in Humans

doi: 10.64898/2026.03.13.26348310

Figure Lengend Snippet: In vivo degradation patterns of Moderna vaccine mRNA in human blood evaluated using ten two-primer fragments in a duplex PCR assay. (A) Schematic illustration of the ten two-primer fragments, each targeting two regions of the Moderna vaccine mRNA sequence in the duplex ddPCR assay to assess degradation patterns of vaccine mRNA. (B) Vaccine mRNA integrity in plasma from six subjects at days 1, 4, and 7 post-Moderna vaccination (three subjects received the bivalent ancestral + BA.1 vaccine and three received the bivalent ancestral + BA.5 vaccine) assessed using the ten fragments. (C) Comparison of mRNA integrity across the ten fragments in plasma samples (day 1 post-vaccination), neat Moderna vaccine, and synthetic Moderna vaccine mRNA. (D,E) Spearman correlation analysis between mRNA integrity in plasma at day 1 post-vaccination and mRNA integrity in (D) neat Moderna vaccine or (E) synthetic Moderna vaccine mRNA. (F,G) Comparison of intact mRNA decay rates across (F) the ten fragments or (G) the six subjects. (H) Best-fit decay slopes of intact mRNA across six donors, with each data point representing the average decay rate calculated from ten individual fragments. For each donor, decay rates were estimated separately for each fragment, and the mean of these ten fragment-specific rates was used to represent the donor-level decay slope. As the decay slopes of donors 2 and 5 overlap, the curve of donor 5 was plotted with higher thickness than that of donor 2 to improve readability. In (C,F), mRNA integrity (%) and decay rates in plasma samples are shown as the mean with upper and lower bound of 95% confidence intervals calculated across six donors.

Article Snippet: As a reference, synthetic spike mRNA, synthesized based on the putative Moderna vaccine mRNA sequence, was largely intact across all ten fragments (green triangles in , mean integrity 86.7%, range 82.4–93.7%) and did not show a significant correlation with the fragment-by-fragment profile observed in blood ( ).Together, these data suggest that (i) the pattern of fragment integrity detected in blood at day 1 largely reflects the formulation’s starting integrity profile; (ii) there was minimal further degradation between vaccination and one day post-vaccination, when mRNA–LNPs travel in vivo into the blood; (iii) the integrity loss of vaccine product is biased toward the 3′-proximal regions of the transcript.

Techniques: In Vivo, Sequencing, Clinical Proteomics, Comparison

Journal: medRxiv

Article Title: In Vivo Blood Kinetics and Transcript Integrity of Three mRNA–Lipid Nanoparticle Vaccines in Humans

doi: 10.64898/2026.03.13.26348310

Figure Lengend Snippet: A) Three cohort of human subjects were recruited who received either Moderna, Pfizer, or mRNA-RBD vaccination. B) Serial blood samples were collected before and after vaccination and analyzed by ddPCR, mass spectrometry and ELISA to quantify vaccine mRNA, ionizable lipid, and antibody response (anti-PEG and anti-spike), respectively.

Article Snippet: Here, we analyzed serial blood samples from participants receiving licensed Moderna or Pfizer spike mRNA vaccines or an investigational RBD mRNA–LNP vaccine (hereafter referred to as “mRNA–RBD”) from a phase I clinical trial ( ) .

Techniques: Mass Spectrometry, Enzyme-linked Immunosorbent Assay

Journal: medRxiv

Article Title: In Vivo Blood Kinetics and Transcript Integrity of Three mRNA–Lipid Nanoparticle Vaccines in Humans

doi: 10.64898/2026.03.13.26348310

Figure Lengend Snippet: Comparison of in vivo vaccine mRNA kinetics in human blood following three types of SARS-CoV-2 mRNA vaccination (Moderna, Pfizer, or mRNA-RBD). (A–C) Longitudinal vaccine mRNA concentrations (copies µL −1 ) in human blood from seven cohorts receiving either (A) Moderna bivalent ancestral + BA.1, bivalent ancestral + BA.5, or monovalent XBB.1.5; (B) Pfizer; or (C) mRNA-RBD at 10, 20, or 50 µg doses. The lower limit of quantification (LLOQ; dashed line) was determined from linear standard curves (Figure S1D–G). In panel A, two the lower limits of quantifications (LLOQs) are shown: 0.4 copies µL −1 for Moderna XBB.1.5 (dark blue dashed line) and 0.93 copies µL −1 for Moderna bivalent vaccines (light blue dashed line). Undetected samples (0 copies μL −1 ) were plotted with open symbols. (D–G) Comparison of (D) mRNA concentration at day 6–7 post-vaccination, (E) post-peak mRNA decay rates, (F) post-peak area under the curve (AUC) of mRNA kinetics in blood, and (G) averaged mRNA kinetics across donors among the three vaccine types. In (D–F), each dot represents one participant, and the horizontal line indicates the median. In (G), averaged mRNA kinetics are shown as mean predictions from the best-fit linear model, with shaded regions indicating the 95% confidence interval bounds. Statistical analysis was performed using the nonparametric Kruskal–Wallis test with Dunn’s multiple comparisons in (D, F) and the likelihood ratio test in (E).

Article Snippet: Here, we analyzed serial blood samples from participants receiving licensed Moderna or Pfizer spike mRNA vaccines or an investigational RBD mRNA–LNP vaccine (hereafter referred to as “mRNA–RBD”) from a phase I clinical trial ( ) .

Techniques: Comparison, In Vivo, Vaccines, Concentration Assay

Journal: medRxiv

Article Title: In Vivo Blood Kinetics and Transcript Integrity of Three mRNA–Lipid Nanoparticle Vaccines in Humans

doi: 10.64898/2026.03.13.26348310

Figure Lengend Snippet: Comparison of in vivo ionizable lipid kinetics in human blood following Moderna, Pfizer, or mRNA-RBD vaccination. (A–C) Longitudinal ionizable lipid concentrations (ng mL −1 ) in human blood from seven cohorts who received either (A) Moderna bivalent ancestral + BA.1, bivalent ancestral + BA.5, or monovalent XBB.1.5 (formulated with SM-102); (B) Pfizer (formulated with ALC-0315); or (C) mRNA-RBD (formulated with Dlin-MC3-DMA) vaccination at 10, 20, or 50 µg doses. (D–G) Comparison of (D) ionizable lipid concentration at day 6–7 post-vaccination, (E) post-peak ionizable lipid decay rates, (F) post-peak AUC of ionizable lipid kinetics in blood, and (G) averaged ionizable lipid kinetics across donors among the three vaccine types. In (D–F), each dot represents one participant, and the horizontal line indicates the median. In (G), averaged ionizable lipid kinetics are shown as mean predictions from the best-fit linear model, with shaded regions indicating the 95% confidence interval bounds. Statistical analysis was performed using the nonparametric Kruskal–Wallis test with Dunn’s multiple comparisons in (D, F) and the likelihood ratio test in (E).

Article Snippet: Here, we analyzed serial blood samples from participants receiving licensed Moderna or Pfizer spike mRNA vaccines or an investigational RBD mRNA–LNP vaccine (hereafter referred to as “mRNA–RBD”) from a phase I clinical trial ( ) .

Techniques: Comparison, In Vivo, Concentration Assay

Journal: medRxiv

Article Title: In Vivo Blood Kinetics and Transcript Integrity of Three mRNA–Lipid Nanoparticle Vaccines in Humans

doi: 10.64898/2026.03.13.26348310

Figure Lengend Snippet: Comparison of in vivo vaccine mRNA integrity in human blood between Moderna and Pfizer vaccines. (A,B) Longitudinal vaccine mRNA integrity in human blood from four cohorts who received either (A) Moderna bivalent ancestral + BA.1, bivalent ancestral + BA.5, or monovalent XBB.1.5 or (B) Pfizer vaccination. (C,D) Longitudinal intact vaccine mRNA concentration (copies µL −1 ) in human blood from the four cohorts. The LLOQ (shown as a dashed line) was determined based on the linear standard curves of vaccine mRNA (Figure S1D–F). In panel C, two LLOQs are shown: 0.4 copies µL −1 for Moderna XBB.1.5 (dark blue dashed line) and 0.93 copies µL −1 for Moderna bivalent vaccines (light blue dashed line). Undetected samples (0 copies μL −1 ) were plotted with open symbols. (E–G) Comparison of (E) post-peak intact mRNA decay rates, (F) post-peak AUC of intact mRNA kinetics in blood, and (G) averaged intact mRNA kinetics across donors between the two vaccine types. In (E,F), each dot represents one participant, and the horizontal line indicates the median. In (G), averaged intact mRNA kinetics are shown as mean predictions from the best-fit linear model, with shaded regions indicating the 95% confidence interval bounds. Statistical analysis was performed using the nonparametric Mann−Whitney U test in (F) and the likelihood ratio test in (E).

Article Snippet: Here, we analyzed serial blood samples from participants receiving licensed Moderna or Pfizer spike mRNA vaccines or an investigational RBD mRNA–LNP vaccine (hereafter referred to as “mRNA–RBD”) from a phase I clinical trial ( ) .

Techniques: Comparison, In Vivo, Vaccines, Concentration Assay, MANN-WHITNEY

Journal: medRxiv

Article Title: In Vivo Blood Kinetics and Transcript Integrity of Three mRNA–Lipid Nanoparticle Vaccines in Humans

doi: 10.64898/2026.03.13.26348310

Figure Lengend Snippet: Comparison of in vivo decay kinetics of vaccine mRNA and ionizable lipids in human blood following Moderna, Pfizer, or mRNA-RBD vaccination. (A) Best-fit decay slopes of total mRNA, intact mRNA, and ionizable lipids across the three vaccines. The response at the peak time point for each parameter was normalized to 100%, and the percentage change over time illustrates the decline estimated from the best-fit linear model. (B) Half-life of total mRNA, intact mRNA, and ionizable lipids from the three vaccines, shown as the mean with upper and lower bound of 95% confidence intervals calculated across multiple donors in each cohort.

Article Snippet: Here, we analyzed serial blood samples from participants receiving licensed Moderna or Pfizer spike mRNA vaccines or an investigational RBD mRNA–LNP vaccine (hereafter referred to as “mRNA–RBD”) from a phase I clinical trial ( ) .

Techniques: Comparison, In Vivo, Vaccines

Journal: medRxiv

Article Title: In Vivo Blood Kinetics and Transcript Integrity of Three mRNA–Lipid Nanoparticle Vaccines in Humans

doi: 10.64898/2026.03.13.26348310

Figure Lengend Snippet: Comparison of anti-PEG antibody levels in human blood before and after Moderna, Pfizer, or mRNA-RBD vaccination. (A,B) Comparison of plasma anti-PEG IgG and IgM endpoint titers before vaccination (Pre-Vax) and after vaccination (Post-Vax) for the three vaccine types. (C,D) Cross-comparison of fold changes (Post-Vax/Pre-Vax) in anti-PEG IgG and IgM endpoint titers among the three vaccine types. In (C,D), each dot represents one participant, and the horizontal line indicates the mean. Statistical analysis was performed using the nonparametric Wilcoxon matched-pairs signed rank test in (A,B) and the nonparametric Kruskal–Wallis test with Dunn’s multiple comparisons in (C,D).

Article Snippet: Here, we analyzed serial blood samples from participants receiving licensed Moderna or Pfizer spike mRNA vaccines or an investigational RBD mRNA–LNP vaccine (hereafter referred to as “mRNA–RBD”) from a phase I clinical trial ( ) .

Techniques: Comparison, Clinical Proteomics

Journal: medRxiv

Article Title: In Vivo Blood Kinetics and Transcript Integrity of Three mRNA–Lipid Nanoparticle Vaccines in Humans

doi: 10.64898/2026.03.13.26348310

Figure Lengend Snippet: In vivo degradation patterns of Moderna vaccine mRNA in human blood evaluated using ten two-primer fragments in a duplex PCR assay. (A) Schematic illustration of the ten two-primer fragments, each targeting two regions of the Moderna vaccine mRNA sequence in the duplex ddPCR assay to assess degradation patterns of vaccine mRNA. (B) Vaccine mRNA integrity in plasma from six subjects at days 1, 4, and 7 post-Moderna vaccination (three subjects received the bivalent ancestral + BA.1 vaccine and three received the bivalent ancestral + BA.5 vaccine) assessed using the ten fragments. (C) Comparison of mRNA integrity across the ten fragments in plasma samples (day 1 post-vaccination), neat Moderna vaccine, and synthetic Moderna vaccine mRNA. (D,E) Spearman correlation analysis between mRNA integrity in plasma at day 1 post-vaccination and mRNA integrity in (D) neat Moderna vaccine or (E) synthetic Moderna vaccine mRNA. (F,G) Comparison of intact mRNA decay rates across (F) the ten fragments or (G) the six subjects. (H) Best-fit decay slopes of intact mRNA across six donors, with each data point representing the average decay rate calculated from ten individual fragments. For each donor, decay rates were estimated separately for each fragment, and the mean of these ten fragment-specific rates was used to represent the donor-level decay slope. As the decay slopes of donors 2 and 5 overlap, the curve of donor 5 was plotted with higher thickness than that of donor 2 to improve readability. In (C,F), mRNA integrity (%) and decay rates in plasma samples are shown as the mean with upper and lower bound of 95% confidence intervals calculated across six donors.

Article Snippet: Here, we analyzed serial blood samples from participants receiving licensed Moderna or Pfizer spike mRNA vaccines or an investigational RBD mRNA–LNP vaccine (hereafter referred to as “mRNA–RBD”) from a phase I clinical trial ( ) .

Techniques: In Vivo, Sequencing, Clinical Proteomics, Comparison