Fig. 9: Antibody responses, morbidity and mortality following reinfection or challenge of SARS-CoV-2 SA variant. | Nature Communications

Fig. 9: Antibody responses, morbidity and mortality following reinfection or challenge of SARS-CoV-2 SA variant.

From: SARS-CoV-2 B.1.1.7 (alpha) and B.1.351 (beta) variants induce pathogenic patterns in K18-hACE2 transgenic mice distinct from early strains

Fig. 9: Antibody responses, morbidity and mortality following reinfection or challenge of SARS-CoV-2 SA variant.

K18-hACE2 mice that survived from prior infection of USA-WA1/2020 (WA) of lineage A bearing 614D or New York-PV09158/2020 (NY) of lineage B.1.3 bearing 614G were reinfected at 6–8 weeks later with USA/CA_CDC_5574/2020 (CA) of lineage B.1.1.7 or hCoV-19/South Africa/KRISP-EC-K005321/2020 (SA) of lineage B.1.351 at the dose of 102 TCID50/mouse in an ABSL-3 biocontainment. Right before reinfection, mouse sera were analyzed for (a) IgG titers specific for spike (S) or receptor binding domain (RBD) by ELISA or (b) microneutralization (MN) titers for SARS-CoV-2 and variants (n = 16 mice/group). Body weight (BW) and survival of mice from prior infection (n = 8 mice/group) and naïve K18-hACE2 mice (n = 3 mice/group) were monitored for two weeks after reinfection of (c) CA (B.1.1.7) or (d) SA (B.1.351) variant. Separate sets of K18-hACE2 mice were immunized intramuscularly with RBD or S emulsified with AS03-like adjuvant and were challenged with 103 TCID50/mouse of NY (614G) or 102 TCID50/mouse of SA (B.1.351). (e) Serum IgG ELISA titers specific for RBD or S or (f) MN titers for SARS-CoV-2 and variants before challenge (n = 8 mice/group). BW and survival of immunized mice (n = 4 mice/group) and naïve K18-hACE2 mice (n = 3 mice/group) were monitored for two weeks after challenge of (g) NY (614G) or (h) SA (B.1.351) variant. Short lines represent geometric means and dotted horizontal lines indicate the limit of detection. BW are expressed as mean ± s.e.m. *p < 0.05, **p < 0.01, ***p < 0.001 and **** p < 0.0001 by one-way nonparametric ANOVA with Dunn’s multiple comparisons test after log-transformation of MN titers. (d) and (h) were conducted at the same time with the same naïve mice as the control.

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