Fig. 2: SM-102 elicits comparable inflammatory response but higher antibody production in mice compared to ALC-0315.

a Timeline of mouse immunization and bleeding. Ten BALB/c mice per group were intramuscularly vaccinated at the indicated days, each time with 1 μg SARS-CoV-2 spike mRNA-LNP prepared with the indicated ionizable lipid. Blood was collected at the indicated time points to measure cytokines and neutralizing antibodies. b Pro-inflammatory cytokines/chemokines in the plasma collected at day 2 were detected using the murine inflammation kit and analyzed by Accuri Flow cytometer. Data are presented as Mean ± SEM of n = 10 mice per group. Cytokine levels in the d22 plasma are presented in Supplementary Fig. 1. c, d SARS-CoV-2 pseudovirus (PV) was preincubated with or without (presented at x = − 6) serially diluted plasma collected at day 14 c or 35 d. H1299-hACE2 cells were incubated with these preincubated mixes and analyzed 24 h later by measuring luciferase activity. Entry of SARS-CoV-2 PV in the presence of immune plasma relative to that in the absence of plasma is shown. Each dot on the curve represents the average value from ten mice. The dashed lines in the figures indicate 50% neutralization. e, f Violin plots show the Neut₅₀ value of individual mouse plasmas (n = 10 per group) collected at day 14 e or 35 f. The central thick lines indicate the median of ten Neut₅₀ values per group. Statistical significance among the groups was analyzed by one-way ANOVA with Tukey’s multiple comparisons test (ns, not significant; *p < 0.05, **p < 0.01, ***p < 0.001, and ****p < 0.0001).