Cross-protection induced by highly conserved human B, CD4+, and CD8+ T-cell epitopes-based vaccine against severe infection, disease, and death caused by multiple SARS-CoV-2 variants of concern

Since early 2020, several SARS-CoV-2 variants of concern (VOCs) continue to emerge, evading waning antibody mediated immunity produced by the current Spike-alone based COVID-19 vaccines. This caused a prolonged and persistent COVID-19 pandemic that is going to enter its fifth year. Thus, the need remains for innovative next generation vaccines that would incorporate protective Spike-derived B-cell epitopes that resist immune evasion. Towards that goal, in this study we (i) Screened the sequences of Spike among many VOCs and identified conserved and non-conserved linear B-cell epitopes; (ii) Compared titers and neutralization antibodies specific to these conserved and non-conserved B-cell epitopes from serum of symptomatic and asymptomatic COVID-19 patients that were exposed to multiple VOCs across the 5-year COVID-19 pandemic, and (iii) Compared protective efficacy of conserved versus non-conserved B-cell epitopes against the most pathogenic Delta variant in a humanized ACE-2/HLA transgenic mouse model. We found robust conserved B-cell epitope-specific antibody titers and neutralization in sera from asymptomatic COVID-19 patients. In contrast, sera from symptomatic patients contained weaker antibody responses specific to conserved B-cell epitopes. A multi-epitope COVID-19 vaccine that incorporated the conserved B-cell epitopes, but not the non-conserved B-cell epitopes, significantly protected the ACE2/HLA-transgenic mice against infection and COVID-19-like symptoms caused by the Delta variant. These findings underscore the importance of conserved B-cell epitopes in generating robust protective immunity against severe COVID-19 symptoms caused by various VOCs, providing valuable insights for the development of broad-spectrum next generation Coronavirus vaccines capable of conferring cross-variant protective immunity.

show abstract

Spike mRNA Vaccine Encapsulated in a Lipid Nanoparticle Composed of Phospholipid 1,2-Dioleoyl-sn-Glycero-3-Phosphoethanolamine Induced Potent B- and T-cell Responses Associated with Protection against COVID-19 in Hamsters

Quadiri,

Prakash,

Zayou

et al. 2024

Preprint

View full text Add to dashboard Cite

Lipid nanoparticles (LNPs) have recently emerged as one of the most advanced vehicle platforms for efficient in vivo delivery of nucleoside-modified mRNA vaccine, particularly for COVID-19. LNPs comprise four different lipids: ionizable lipids, helper or neutral lipids, cholesterol, and lipids attached to polyethylene glycol (PEG). Studies on using the mRNA-LNP platform for vaccines have largely focused on the nucleic acid cargo with less attention to the LNP vehicle. While the LNPs protect mRNA from degradation and efficiently deliver the mRNA to antigen-presenting cells the effect of lipid composition and biophysical properties on the immunogenic and protective mRNA vaccine remain to be fully elucidated. In the present study, we used SARS-CoV-2 Spike-mRNA as a prototype vaccine, to study the effect of 4 different of LNPs with various lipid compositions. We demonstrate that when the same Spike-mRNA was delivered in the LNP4 formulation based on phospholipid 1,2-dioleoyl-sn-glycero-3-Phosphoethanolamine it outperformed the immunogenicity and protective efficacy of three LNPs (LNP1, LNP2, and LNP3) that are based on different lipids. Compared to other three LNPs, the LNP4: (i) enhanced phenotypic and functional maturation of dendritic cells; (ii) induced strong T-cell responses, (iii) increased secretion of proinflammatory, pro-follicular T helper (Tfh) cell cytokines; (iv) induced higher neutralization IgG titers; and (v) and provided better protection against SARS-CoV-2 infection and COVID-19 in the hamster model. We discussed the potential mechanisms by which LNP which include the phospholipid 1,2-dioleoyl-sn-glycero-3-phosphoethanolamine may activate protective B- and T-cell responses.

show abstract

Cross-protection induced by highly conserved human B, CD4+, and CD8+ T-cell epitopes-based vaccine against severe infection, disease, and death caused by multiple SARS-CoV-2 variants of concern

Cited by 7 publications

References 92 publications

Production and evaluation of a bivalent adjuvant inactivated vaccine against infectious hematopoietic necrosis virus and infectious pancreatic necrosis virus

Production and evaluation of a bivalent adjuvant inactivated vaccine against infectious hematopoietic necrosis virus and infectious pancreatic necrosis virus

Dynamics of Spike-Specific Neutralizing Antibodies Across Five-Year Emerging SARS-CoV-2 Variants of Concern Reveal Conserved Epitopes that Protect Against Severe COVID-19

Spike mRNA Vaccine Encapsulated in a Lipid Nanoparticle Composed of Phospholipid 1,2-Dioleoyl-sn-Glycero-3-Phosphoethanolamine Induced Potent B- and T-cell Responses Associated with Protection against COVID-19 in Hamsters

Contact Info

Product

Resources

About