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). a-e Reproduced with permission from ref [90].