Synthesis of Liposomes Conjugated with CpG Oligonucleotide and Loaded with a Set of T-Cell Epitopes of the SARS-CoV-2 Virus

Abstract

The synthesis of lipid conjugate of immunostimulatory oligodeoxyribonucleotide CpG-ODN (PD-CpG-DOPE) is described. Liposomes loaded with a composition of T-cell epitopes of the SARS-CoV-2 virus (7 peptides) and carrying PD-CpG-DOPE conjugate in the membrane, including lyophilized liposomes suitable for long-term storage, were prepared. In vitro experiments on mouse peritoneal exudate cells showed a tendency to increase the immunogenicity of liposomes with peptides when PD-CpG-DOPE conjugate was introduced into the lipid bilayer, compared with the addition of the (commercial) phosphorothioate derivative of CpG-ODN in solution.