Lipid nanoparticle-encapsulated mRNA antibody provides long-term protection against SARS-CoV-2 in mice and hamsters

Abstract

Monoclonal antibodies represent important weapons in our arsenal to against the COVID-19 pandemic. However, this potential is severely limited by the time-consuming process of developing effective antibodies and the relative high cost of manufacturing. Herein, we present a rapid and cost-effective lipid nanoparticle (LNP) encapsulated-mRNA platform for in vivo delivery of SARS-CoV-2 neutralization antibodies. Two mRNAs encoding the light and heavy chains of a potent SARS-CoV-2 neutralizing antibody HB27, which is currently being evaluated in clinical trials, were encapsulated into clinical grade LNP formulations (named as mRNA-HB27-LNP). In vivo characterization demonstrated that intravenous administration of mRNA-HB27-LNP in mice resulted in a longer circulating half-life compared with the original HB27 antibody in protein format. More importantly, a single prophylactic administration of mRNA-HB27-LNP provided protection against SARS-CoV-2 challenge in mice at 1, 7 and even 63 days post administration. In a close contact transmission model, prophylactic administration of mRNA-HB27-LNP prevented SARS-CoV-2 infection between hamsters in a dose-dependent manner. Overall, our results demonstrate a superior long-term protection against SARS-CoV-2 conferred by a single administration of this unique mRNA antibody, highlighting the potential of this universal platform for antibody-based disease prevention and therapy against COVID-19 as well as a variety of other infectious diseases.

Trial registration: ClinicalTrials.gov NCT03829384.

Conflict of interest statement

C.-F.Q. and B.Y. have filed a patent related to the technology reported in this article. B.Y., X.Z., S.X., X.-H.D., D.-D.L., and X.-J.Z. are employee of Suzhou Abogen Biosciences. L.-Z.X has an ownership in Sinocelltech. The other authors have no conflicts of interest to declare.

© 2022. The Author(s).

Figures

Fig. 1. Rational design and characterization of the mRNA antibody.

a Design and encapsulation of an mRNA antibody mRNA-HB27-LNP. b HB27 antibody expression in Vero, 293 T and Expi293F cells at 24 h after transfection with mRNA-HB27 using ELISA assay. Data are shown as mean ± SEM. Data are analyzed by One-way ANOVA with multiple comparisons (****P < 0.0001). c Inhibition of SARS-CoV-2 infection in Vero cells at 24 h after transfection with 1 μg of mRNA-HB27 by Immunofluorescence assay. SARS-CoV-2 S protein was stained in green, and DAPI in blue. Scale bars, 100 μm. d, e The antibody concentration and NT50 titer of serum samples in mice. Briefly, female BALB/c mice (n = 4/group) were i.v. administrated with the indicated dose of mRNA-HB27-LNP or Placebo. Then, mice sera at 24 h post administration were measured by ELISA (d) and SARS-CoV-2 pseudovirus neutralization assay (e), respectively. Dotted lines indicate the limits of detection. Data are shown as mean ± SEM. f Intravenous injection of reporter mRNA-LNPs for in vivo imaging in mice. IVIS Spectrum image (6 h post-injection) of female BALB/c mice were injected with 10 μg of FLuc-encoding reporter mRNA-LNP by the intravenous route.

Fig. 2. Prophylactic efficacy of mRNA-HB27-LNP against SARS-CoV-2 in mice.

a Experimental design. Briefly, groups of 8-month-old female BALB/c mice (n = 32) were i.v. administrated with a single dose of 1 mg/kg (purple), 0.2 mg/kg (blue), or 0.4 mg/kg (orange) of mRNA-HB27-LNP and Placebo (red) at 1 days before challenge with 6 × 103 PFU of MASCp36, and the clinical symptoms and mortality were recorded for 14 days. Mice (n = 3 per group) were sacrificed at 3 dpi for viral detection and histopathological analysis. b Survival curves of BALB/c mice administrated with the indicated dose of mRNA-HB27-LNP (n = 5 per group) and Placebo (n = 5). Data were analyzed by Wilcoxon log-rank survival test. (***P < 0.001, ****P < 0.0001). c viral sgRNA loads of lung tissues at 3 dpi were determined by RT-qPCR, respectively. Data are represented as mean ± SEM. Dashed lines represents limit of detection (n = 3 per group). Significance was calculated using Ordinary one-way ANOVA Multiple comparisons (****P < 0.0001). d Histopathological analysis of lung tissues at 3 dpi. Scale bar, 100 µm. e Experimental design. Briefly, the 8-month-old male BALB/c mice received i.v. administration of 1 mg/kg of mRNA-HB27-LNP (n = 5) and Placebo (n = 5), respectively. At 1 day post administration, mice were i.n. challenged with 1 × 104 PFU of SARS-CoV-2 Beta variant strain, and the lung tissues were collected at 5 days after challenge for detection of viral burden determination (by RT-qPCR) and histopathological analysis. f Viral sgRNA loads of lung tissues at 5 dpi were determined by RT-qPCR. Data are represented as mean ± SEM. Significance was calculated using unpaired t-test (****P < 0.0001). g Histopathological analysis of lung tissues at 5 dpi. Scale bar, 100 µm.

Fig. 3. mRNA-HB27-LNP prevents SARS-CoV-2 transmission in hamsters.

a Experimental design. Briefly, groups of 6–8-week-old female Syrian golden hamsters were i.v. injected with 0.3 or 1 mg/kg of mRNA-HB27-LNP (n = 2 per group) or placebo (n = 4). 24 h later, each of treatment hamster were transferred to a new cage and were cohoused with one index hamster in a one-to-one manner. The index hamsters (n = 8) were infected with 1 × 104 PFU of SARS-CoV-2 through the intranasal route at 1 h prior to cohouse. The lung tissues of hamster were collected at 4 dpi for following-up viral burden determination (by RT-qPCR) and histopathological analysis. b Viral sgRNA loads in lung tissues of hamsters at 4 dpi were determined by RT-qPCR. The dotted line in panel shows the limit of detection of the assay. c Histopathological analysis of each group of lung tissues at 5 dpi. Representative images from 16 hamsters are shown. Scale bar, 200 µm.

Fig. 4. mRNA-HB27-LNP provides a long-term protection against SARS-CoV-2 challenge in mice.

a The antibody concentration of serum in mice by ELISA. Briefly, groups of 6–8-week-old ICR mice were i.v. administrated with a single dose of 1 mg/kg of HB27 (n = 4) and HB27-mRNA-LNP (n = 4), respectively. At indicated times post administration, sera of mice were measured by ELISA. Dotted lines indicate the limits of detection. b Analysis of antibody pharmacokinetics in serum after the i.v. administration with a single dose of HB27 and mRNA-HB27-LNP. Calculations were performed using WinNolin. c NT50 of serum in mice by VSV-based SARS-CoV-2 pseudovirus. Data are shown as mean ± SEM. Dashed lines represents limit of detection. d, e Experimental design. Briefly, groups of 8-month-old female BALB/c mice were i.v. administrated with a single dose of 1 mg /kg of HB27 or mRNA-HB27-LNP (n = 4 or 5) and Placebo (n = 5). Then at 7 days or 63 days post administration, mice were challenged with 6 × 103 PFU of MASCp36, respectively, and the clinical symptoms and mortality were recorded for 14 days. Survival curves of mice after lethal challenge by MASCp36 at 7 days (d) and 63 days (e) after the i.v. administration. Data were analyzed by Wilcoxon log-rank survival test (**P < 0.01).