Abstract: A peptide vaccine complexed so that the peptide vaccine can be delivered specifically to the surface of specific immune cells and a method for delivering a peptide vaccine specifically to the surface of specific immune cells. The peptide vaccine is combined with an IgG binding peptide capable of binding to an IgG that is an agonist against molecules on the surface of specific immune cells such as dendritic cells.

Abstract: Problem to be solved: An object of the present invention is to obtain medicinal effect that could not be obtained by conventional peptide vaccines that activate and proliferate a CD8-positive CTL by administering a Class II epitope as a peptide vaccine. Solution: The inventors of the present invention have found, as a result of diligent examination on the aforementioned problems, that these problems can be solved by acquiring a peptide having a partial amino acid sequence containing a mutated amino acid of a neoantigen expressed in cancer cells and being an epitope presented by a Class II molecule.