Purpose: SARS-CoV-2 caused COVID-19 pandemic overwhelms global health care. COVID-19 vaccination is crucialfor preventing infection and controlling the pandemic. Multiple safe and effective vaccines are available worldwide.Nanotechnology provides the opportunity for construction of modern transport devices such as nanoparticles for a varietyof applications in the field of medicine. A novel experimental protocol for the formation of saponin-cholesterol-phospholipid nanoparticles of vesicular structure has been developed and applied to prepare stable nanoparticles usingescin or glycyrrhizin as saponin.Here, we describe the design and development of a next-generation multi-epitope vaccine for SARS-CoV-2, consistingof epitopes recognizable by T-cells.Methods: Structure-based and sequence-based immunoinformatics methods were used to derive models for selection ofMHC binders specific for the mouse strain used in the study among a set of human SARS-CoV-2 T-cell epitopes identifiedby convalescent patients with COVID-19. The binders were synthesized and included in a multi-epitope vaccineprototype.The methods for nanoparticle construction include a sonication, thus forming stable unilamellar vesicles. Tests and assaysfor cell viability, erythrocyte hemolysis, flow cytometry, and fluorescent microscopy analyses have been performed.Results: The immunogenicity of the vaccine prototype designed in the present study was tested on humanized-ACE2transgenic B6.Cg-Tg(K18-ACE2)2Prlmn/J mice by in vitro, in vivo, and ex vivo immunoassays. The animals wereimmunized with a mix of predicted MHC-I, or MHC-II, or MHC-I/MHC-II peptide epitopes in CFA, and boosted withpeptides in IFA. Immunization with SARS-Cov-2 epitopes remodels lymphocyte profile. A weak humoral response andsignificant production of IL-4 and IFN-γ from T cells were found after vaccination of the animals.By selecting appropriate component ratios, stable and safe particles were formulated with respect to the tested bio-cells.The versatility of these nanoparticles allows for the encapsulation of various molecules, either within the vesicle interiorfor water-soluble components or within the vesicle walls for hydrophobic components. These particles are successfulincluded into isolated mouse macrophages.Conclusion: The multi-epitope vaccine prototype presented in this study demonstrates immunogenicity in mice andshows potential for human vaccine construction.This work was supported by the Bulgarian Science Fund (Grant No KP-06-DK1/2/2021).