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Link to original content: http://pubmed.ncbi.nlm.nih.gov/39054338/
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. 2024 Jul 25;9(1):133.
doi: 10.1038/s41541-024-00922-z.

Universal subunit vaccine protects against multiple SARS-CoV-2 variants and SARS-CoV

Gang Wang #  1 , Abhishek K Verma #  2 , Juan Shi #  1 , Xiaoqing Guan  1 , David K Meyerholz  3 , Fan Bu  4   5 , Wei Wen  4   5 , Bin Liu  6 , Fang Li  7   8 , Stanley Perlman  9   10 , Lanying Du  11
Affiliations

Universal subunit vaccine protects against multiple SARS-CoV-2 variants and SARS-CoV

Gang Wang et al. NPJ Vaccines. .

Abstract

Although Omicron RBD of SARS-CoV-2 accumulates many mutations, the backbone region (truncated RBD) of spike protein is highly conserved. Here, we designed several subunit vaccines by keeping the conserved spike backbone region of SARS-CoV-2 Omicron BA.1 subvariant (S-6P-no-RBD), or inserting the RBD of Delta variant (S-6P-Delta-RBD), Omicron (BA.5) variant (S-6P-BA5-RBD), or ancestral SARS-CoV-2 (S-6P-WT-RBD) to the above backbone construct, and evaluated their ability to induce immune responses and cross-protective efficacy against various SARS-CoV-2 variants and SARS-CoV. Among the four subunit vaccines, S-6P-Delta-RBD protein elicited broad and potent neutralizing antibodies against all SARS-CoV-2 variants tested, including Alpha, Beta, Gamma, and Delta variants, the BA.1, BA.2, BA.2.75, BA.4.6, and BA.5 Omicron subvariants, and the ancestral strain of SARS-CoV-2. This vaccine prevented infection and replication of SARS-CoV-2 Omicron, and completely protected immunized mice against lethal challenge with the SARS-CoV-2 Delta variant and SARS-CoV. Sera from S-6P-Delta-RBD-immunized mice protected naive mice against challenge with the Delta variant, with significantly reduced viral titers and without pathological effects. Protection correlated positively with the serum neutralizing antibody titer. Overall, the designed vaccine has potential for development as a universal COVID-19 vaccine and/or a pan-sarbecovirus subunit vaccine that will prevent current and future outbreaks caused by SARS-CoV-2 variants and SARS-related CoVs.

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Conflict of interest statement

The authors declare no competing interests. Georgia State University has filed a patent application related to this study, with L.D., G.W., J.S., and F.L. as inventors.

Figures

Fig. 1
Fig. 1. Vaccine constructs and immunization or challenge schedules.
a S-6P-Delta-RBD, S-6P-BA5-RBD, and S-6P-WT-RBD proteins were constructed based on the backbone (truncated RBD) of the spike (S) protein of SARS-CoV-2 Omicron BA.1 subvariant (S-6P-no-RBD). The original S-6P protein (without RBD truncation) was used as a vaccine control. The amino acids (aa) were shown in each construct (the percentage of backbone and RBD: ~5.2:1). b Immunization and challenge schedules. K18-hACE2 (C57BL/6 background) mice were respectively immunized with the above five proteins or PBS control, plus adjuvants, and sera were collected for detection of antibody responses and neutralizing antibodies against SARS-CoV-2 wild-type and multiple strains of variants of concern (VOCs). The immunized mice were challenged with the SARS-CoV-2 Omicron variant, Delta variant, and SARS-CoV, respectively, for evaluation of protective efficacy against viral infection. The immune sera were also evaluated for passive protection against SARS-CoV-2 Delta variant and potential pathological effects. The immunized C57BL/6 mice were tested for vaccine-induced T cell responses and neutralizing antibodies. The images of mice, serum, viruses, and cells were selected from BioRender.com.
Fig. 2
Fig. 2. Cyro-EM structures of S-6P-no-RBD protein and neutralizing ability of subunit vaccines.
a Overview of the cryo-EM map of the truncated spike (S) (i.e., S-6P-no-RBD) protein with structural model inside. The structure is presented in cartoons with tube helices. b Front and top views of the cryo-EM map. c–i Neutralizing antibodies induced by subunit vaccines against multiple variants and ancestral strain of SARS-CoV-2. The purified proteins, including S-6P, S-6P-Delta-RBD, S-6P-BA5-RBD, S-6P-WT-RBD, and S-6P-no-RBD (10 μg/mouse), or PBS control, were intramuscularly (i.m.) injected into K18-hACE2 mice in the presence of adjuvants. The cocktail consisted of the S-6P-Delta-RBD and S-6P-BA5-RBD proteins (5 μg/protein; 10 μg/mouse) with the adjuvants. The mice were boosted twice at 3-week intervals with the same immunogen and adjuvants, as described in Fig. 1. Sera collected from 10 days after the 3rd immunization were evaluated for neutralizing antibodies (Abs) against pseudoviruses encoding the S protein of the ancestral (wild-type, WT) SARS-CoV-2 strain (c), Alpha (d), Beta (e), Gamma (f), and Delta (g) variants, as well as the Omicron BA.1 (h), BA.2 (i), BA.2.75 (j), BA.4.6 (k), and BA.5 (l) subvariants. The NT50 is expressed as 50% neutralizing Ab titers against each pseudovirus infection in 293T cells expressing human angiotensin converting enzyme-2 (hACE2/293T). The data are presented as the mean ± standard deviation of the mean (s.e.m.) of four wells from pooled sera of five mice in each group. The limit of detection for the neutralization assay was 1:5 (c–l). Ordinary one-way ANOVA (Dunnett’s multiple comparison test) was used to compare the statistical differences of neutralizing antibody titers induced by S-6P-Delta-RBD and other vaccination groups. *P < 0.05, **P < 0.01, and ***P < 0.001 designate significant differences between S-6P-Delta-RBD and other vaccination groups. The experiments were repeated twice (c–e, h) or three times (f, g, i–l) to confirm the results.
Fig. 3
Fig. 3. The designed subunit vaccines protected immunized K18-hACE2 mice against infection of SARS-CoV-2 Delta and Omicron variants.
K18-hACE2 mice were immunized with each protein, including S-6P, S-6P-Delta-RBD, S-6P-BA5-RBD, S-6P-WT-RBD, and S-6P-no-RBD, the cocktail (combination of S-6P-Delta-RBD and S-6P-BA5-RBD proteins) in the presence of adjuvants, or PBS plus adjuvants (control), as described in Fig. 1. The immunized mice were respectively challenged with two SARS-CoV-2 variants, Delta and Omicron (BA.1 subvariant), 2 weeks after the 3rd immunization. The mice challenged with a high lethal dose of Delta variant were observed for survivals (a–g) and body weight changes (h) for 14 days after challenge. The data (h) are presented as the mean + s.e.m. of five mice in each group. Ordinary one-way ANOVA (Dunnett’s multiple comparison test) was used to compare the statistical differences of weight changes between S-6P-Delta-RBD and other groups, and there are significant differences between S-6P-Delta-RBD and S-6P-WT-RBD (**P < 0.01) or PBS control group (***P < 0.001). The mice challenged with an optimal dose of Omicron variant (BA.1) were collected for lung tissues two days after viral infection, and detected for viral titers by plaque assay (i) and viral replication by qPCR assay (j). The data (i, j) are presented as the mean ± s.e.m. of five mice in each group. The limit of detection for the plaque assay was 50 plaque forming units (PFU) (i) and for qPCR assay was Cq value of 35 cycles (j). Ordinary one-way ANOVA (Tukey’s multiple comparison test) was used to compare the statistical differences of viral titers and qPCR results among different groups (i, j). *P < 0.05 and ***P < 0.001 designate significant differences among these groups. The experiments were repeated twice, with similar results.
Fig. 4
Fig. 4. Naive K18-hACE2 mice receiving S-6P-Delta-RBD immune sera were prevented against SARS-CoV-2 infection without showing pathological effects.
Naive K18-hACE2 mice were i.p. administered with pooled mouse sera (200 μl/mouse), and then i.n. challenged with SARS-CoV-2 Delta variant 6 h later, followed by evaluation of viral titers, body weight changes, and pathological changes in the lungs 4 days post-challenge. a 50% neutralizing antibody (Ab) titers (NT50) was calculated from pooled sera against SARS-CoV-2 Delta pseudovirus infection in hACE2/293T cells. b Viral titers of challenged mice (PFU/ml of lung tissues) was performed by plaque assay. c Weights were monitored for 4 days post-challenge. d Scoring of edema was calculated based on the H&E-stained lung tissue sections of challenged mice. Edema was scored 0 (none), 1 (< 25%), 2 (26–50%), 3 (51–75%), and 4 (> 75%) of tissue fields, respectively. Representative images are shown as H&E-stained lung tissue sections from challenged mice receiving sera of S-6P (e), S-6P-Delta-RBD (f), S-6P-BA5-RBD (g), S-6P-WT-RBD (h), S-6P-no-RBD (i), the cocktail (combination of S-6P-Delta-RBD and S-6P-BA5-RBD proteins) (j), and PBS plus adjuvants (control) (k). Scale bar (e) represents 170 μm; asterisk (*) (e, g–k) represents edema score. The data (a) are presented as mean ± s.e.m. of four wells of pooled sera. The data (b–d) are presented as mean plus s.e.m. of viral titers, weight changes, and pathological changes (edema score) from five mice in each group. The limit of detection for the neutralization assay was 1:5 (a) and for the plaque assay was 50 PFU (b). Ordinary one-way ANOVA (Dunnett’s multiple comparison test) was used to compare the statistical differences between S-6P-Delta-RBD immune sera and other vaccinated sera (a), and Ordinary one-way ANOVA (Tukey’s multiple comparison test) was used to compare the statistical differences among different groups (b–d). *P < 0.05, **P < 0.01), and ***P < 0.001 designate significant differences among various groups. The experiments were repeated once (b–k) or twice (a), with similar results.
Fig. 5
Fig. 5. The designed subunit vaccines induced SARS-CoV-specific immune responses and protected K18-hACE2 mice against SARS-CoV infection.
K18-hACE2 mice were immunized with S-6P, S-6P-Delta-RBD, S-6P-BA5-RBD, S-6P-WT-RBD, or S-6P-no-RBD, the cocktail (combination of S-6P-Delta-RBD and S-6P-BA5-RBD proteins) in the presence of adjuvants, or PBS plus adjuvants (control), as described in Fig. 1. The immunized mice were challenged with a lethal dose of SARS-CoV (MA15 strain) 2 weeks after the 3rd immunization. The challenged mice were observed for overall survival (a–g) and weight changes (h) for 13 days after SARS-CoV challenge. In a separate experiment, C57BL/6 mice were immunized as described above, collected for sera and splenocytes 4 months after the 3rd immunization, and detected for neutralizing antibodies against pseudotyped SARS-CoV in hACE2/293T cells (i), as well as IFN-γ or TNF-α-producing CD4+ (j, k) and CD8+ (l, m) T cells, respectively. NT50 is expressed as 50% neutralizing antibody (Ab) titers of sera against SARS-CoV pseudovirus in hACE2/293T cells, and the data (i) are presented as the mean plus s.e.m. of four wells from pooled sera of five mice in each group. The limit of detection for the neutralization assay was 1:5. The splenocytes were stimulated with a Fc-fused SARS-CoV RBD protein, and the secreted cytokines were measured by flow cytometry. The data (j–m) are presented as the mean plus s.e.m. of five mice in each group. Ordinary one-way ANOVA (Dunnett’s multiple comparison test) was used to compare the statistical differences between S-6P-Delta-RBD and other vaccinated groups (i), and Ordinary one-way ANOVA (Tukey’s multiple comparison test) was used to compare the statistical differences among different groups (l, m). *P < 0.05, **P < 0.01, and ***P < 0.001 designate significant differences among various groups. The experiments were repeated twice, with similar results.
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References

    1. Zhou, P. et al. A pneumonia outbreak associated with a new coronavirus of probable bat origin. Nature579, 270–273 (2020). 10.1038/s41586-020-2012-7 - DOI - PMC - PubMed
    1. World Health Organization. WHO coronavirus (COVID-19) dashboard. https://covid19.who.int/ (2019).
    1. World Health Organization. Tracking SARS-CoV-2 variants. https://www.who.int/en/activities/tracking-SARS-CoV-2-variants/ (2024).
    1. Harvey, W. T. et al. SARS-CoV-2 variants, spike mutations and immune escape. Nat. Rev. Microbiol.19, 409–424 (2021). 10.1038/s41579-021-00573-0 - DOI - PMC - PubMed
    1. Tuekprakhon, A. et al. Antibody escape of SARS-CoV-2 Omicron BA.4 and BA.5 from vaccine and BA.1 serum. Cell185, 2422–2433.e13 (2022). 10.1016/j.cell.2022.06.005 - DOI - PMC - PubMed

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