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[Preprint]. 2021 Mar 27:2021.03.26.437274. [Version 1] doi: 10.1101/2021.03.26.437274

Fig. 1. SARS-CoV-2 SApNP vaccines induce broadly neutralizing antibody responses to three variants of concern.

Fig. 1.

(A) Molecular surface representations of vaccine constructs, including two spikes (S2PECTO-5GS-1TD0 and S2GΔHR2-5GS-1TD0) and three spike-presenting SApNPs (S2GΔHR2-5GS-ferritin (FR), S2GΔHR2-5GS-E2p-LD4-PADRE (E2p-L4P), and S2GΔHR2-10GS-I3-01v9-LD7-PADRE (I3-01v9-L7P)). Representative negative-stain EM (nsEM) image of S2GΔHR2-10GS- I3-01v9-L7P SApNPs is shown on the right. (B) Neutralization of the original Wuhan-Hu-1 strain by mouse plasma induced by 5 different vaccines at week 5 after two intraperitoneal injections. ID50 titers derived from SARS-CoV-2-pp neutralization assays are plotted, with average ID50 values labeled on the plots. (C) Mouse plasma neutralization against the original Wuhan-Hu-1 strain and three variants, B.1.1.7, B1.351, and P.1, at week 5 after two intraperitoneal injections of the adjuvanted S2GΔHR2-10GS-I3-01v9-L7P vaccine. Left panels 1-4: percent neutralization plots of individual mice against 4 SARS-CoV-2 strains; Right panel: ID50 plot. In (B) and (C), the plasma samples were generated in the previous study (41), where mice were immunized with 50 μg of adjuvanted vaccine antigen. (D) Neutralization of the original Wuhan-Hu-1 strain by mouse plasma induced the S2GΔHR2 spike and two large S2GΔHR2-presenting SApNPs. Vaccines were administered via footpad injections (0.8 μg/injection, for a total of 3.3 μg/mouse). (E) Mouse plasma neutralization against the original Wuhan-Hu-1 strain and three variants, B.1.1.7, B1.351, and P.1, at week 5 after two footpad injections of the S2GΔHR2 spike and two large S2GΔHR2-presenting SApNPs. In (B)-(E), the ID50 values are plotted as mean ± SEM. The data were analyzed using two-tailed unpaired Student’s t-test for comparison between different vaccine groups or two-tailed paired Student’s t-test for comparison of ID50 titers against SARS-Cov-2 variants using the same plasma samples from a mouse. *p < 0.05, **p < 0.01. (F) Neutralization of four SARS-CoV-2 strains by human monoclonal antibodies including CR3022, B38, CB6, S309, CC12.1, CC12.3, C105, and P2B-2F6. IC50 values are listed and color-coded (white: no neutralization; green to red: low to high). The IC50 values were calculated with the %neutralization range constrained within 0.0-100.0%.