Figure 4.

Immune response following boosting with ferritin nanoparticle multimerization of SARS-2^hg

(A) Design schematic of a multimerized version of SARS-2^hg using SpyTag-SpyCatcher conjugation to a ferritin nanoparticle.

(B) Serum following immunization was assayed in ELISA on day 35 with the wild-type SARS-2 RBD and RBM^hg. Statistical significance was determined using Mann-Whitney U test (^∗p < 0.05). Bars represent mean ± SE.

(C) Day 35 serum titers to the wild-type SARS-2 RBD were also compared with titers against SARS-2^hg and the unconjugated ferritin nanoparticle-SpyCatcher fusion. A Kruskal-Wallis test was performed and detected no significant differences between the serum Ab responses to these three proteins. Bars represent mean ± SE.

(D) Day 35 serum was assayed for neutralization against SARS-2, SARS-1, and WIV1 pseudoviruses. Statistical significance was determined using a Kruskal-Wallis test with post hoc analysis using Dunn’s test corrected for multiple comparisons, and pairwise comparisons pictured without bars were not significant (^∗p < 0.05, ^∗∗p < 0.01, ^∗∗∗p < 0.001). Bars represent mean ± SE.

(E) Day 35 serum was assayed against SARS-2 variant pseudoviruses for neutralization. Statistical significance was determined using a Kruskal-Wallis test with post hoc analysis using Dunn’s test corrected for multiple comparisons, and pairwise comparisons pictured without bars were not significant (^∗p < 0.05). Bars represent mean ± SE.