Immunogenicity of lipopeptides in HLA-A*1101 transgenic mice HLA-A*1101 transgenic mice were immunized twice at intervals of three weeks with lipopeptides which were administered in PBS. Two weeks after the last immunization, the spleens were removed from immunized mice and the ability of splenocytes to produce IFN-γ upon stimulation with peptides was analyzed. Transgenic mice immunized with the three single peptide lipopeptide vaccines had T cells that produced IFN-γ ( Figure 2 ). The lipopeptide vaccines LpKS9 and LpAM9 stimulated higher IFN-γ production than LpRS9 ( Figure 2 ). However, LpKS9-AM9-RS9 with three peptide epitopes linked together did not stimulate strong IFN-γ responses when splenocytes from these mice were exposed to each of the individual peptides in vitro. Only results with LpKS9(KS9) and LpAM9(AM9) achieved statistical significance ( Figure 2 ).