Fig. 3: Mutations of L452R and T478K both benefit to antibody response against Omicron and Delta variants.
From: A self-assembled trimeric protein vaccine induces protective immunity against Omicron variant
a NIH mice were immunized with 10 μg of adjuvant-formulated RBDWT-HR, RBDL452R-HR, RBDT478K-HR, and our RBD-HR/trimer, serum samples were collected on day 56 to assay the neutralizing antibodies against prototype, Delta and Omicron pseudovirus (n = 6 mice per group). b Neutralizing antibody titers in vaccinated mice after two doses of immunization (n = 6 mice per group). c Antigenicity analyses of the SARS-CoV-2 original-strain and Delta-variant RBDs using the Jameson-Wolf method. The antigenic index values for the L452/R452 and T478/K478 pairs are recorded and further presented using histograms. d Neutralizing antibody titers induced by RBDWT-HR, RBDL452R-HR, RBDT478K-HR, and RBD-HR/trimer against mutated psudoviruses containing signal mutation of L452R, T478K or double L452R + T478K substitutions (n = 6 mice per group). e The spike RBD structures highlighting the small two-stranded β-sheet in the middle of the external subdomain. The structures of the Delta (PDB code: 7wbq) and Omicron (PDB code: 7wbp) RBDs are presented in the same orientation and further shown in the left and right panels, respectively. The Delta-specific residue of R452 and omicron-specific residue of R493 are marked. The two anti-parallel β-strands where R452 and R493 locate are highlighted by encircling with red lines. Data are presented as geometric mean values ± SD in a, b and d. P values were conducted by Two-way ANOVA analysis followed by Tukey’s multiple comparisons test. Source data are provided as a Source Data file.
