Effect of Lipid Components on Immunogenicity of Synthetic Fragment of Hepatitis C Virus NS4A Antigen

The aim of this study was to investigate the effect of lipid components on the immunogenicity of a synthetic 24-mer peptide containing B- and Th-epitopes. The synthetic peptide amidated at the C -terminus had the primary structure VIVGRIILSGRPAVIPDREVLYRK, which corresponded to a fragment of the NS4A antigen of the hepatitis C virus. To enhance the immunogenicity, the peptide was acylated at the N ‑terminus with a lipophilic compound 1,3-(dipalmitoylamino)propane-2- O -succinate. A liposomal form of the peptide with a particle size of 160 ± 20 nm and a degree of peptide inclusion of 80% was also obtained. The peptide included in liposomes was stable for three months. The immunogenicity of the peptide, lipopeptide, and peptide in liposomes was studied with regard to the production of antibodies by B cells and cytokines (IFN-γ and IL-2) by specific CD4 + T-lymphocytes in laboratory mice. The 24-mer peptide incorporated in phosphatidylcholine liposomes had the highest immunogenicity; therefore, it is promising for further research on the development of a candidate hepatitis C vaccine.