The invention relates to isolated immunogenic peptides comprising a CD1d binding peptide, and immediately adjacent or separated from said CD1d binding peptide, a redox motif sequence which is further flanked by a histidine or tryptophan amino acids. The invention further relates to these peptides for use as a medicament The invention further relates to methods wherein these peptides are used for generating NKT cells which are cytolytic against cells presenting the cognate antigen.