Fig. 4.
T cell epitope peptide cocktail vaccines elicited robust CD8+ T cell responses in transgenic mice. Thirty-one VEPs restricted by the HLA-A0201 molecule were used to generate three formulations of peptide cocktail vaccines, followed by three rounds of immunizations to HLA-A2/DR1 transgenic C57BL/6 mice. Then, splenocytes were collected 7 days after the last booster and stimulated ex vivo overnight with distinct peptide pools according to single protein followed by IFN-γ ELISPOT and IFN-γ ICS. A Total IFN-γ SFUs responding to all peptide pools in each mouse. B Deconvolution of the total SFUs in each mouse from (A) into the single SARS-CoV-2 proteins. C Total frequency of IFN-γ+ T cells reacting to all peptide pools in the CD3+CD8+ T cell population in each mouse. D Deconvolution of the total frequency in each mouse from (C) into the single SARS-CoV-2 proteins. Control groups: N.S and PLGA-NPs; Vaccine A group: PLGA-NPs/peptides vaccines; Vaccine B group: R848/peptides vaccines; Vaccine C group: poly I: C/peptides vaccines