The invention relates to isolated immunogenic peptides comprising a T-cell epitope derived from a soluble allofactor and a C-(X)2-[CST] or [CST]-(X)2-C motif, which is immediately adjacent or separated from the T-cell epitope by at most 7 amino acids. The application further relates to the use of these peptides in preventing or suppressing an immune response to a soluble allofactor. The invention further relates to the use of these peptides in obtaining populations of soluble allofactor-specific regulatory T cells with cytotoxic properties.
