Epitopes which induce cell death T

An isolated epitope comprising X1-X2-X3-X4-X5, wherein binding of a ligand to the epitope on activated T-cells induces death of the cells, and X1 is Tyr, Trp, His or Met; X2 is Asp; X3 is Ser, Phe, Pro, Glu, or His; X4 is any amino acid; and X5 is Pro, Tyr, His or Trp, and further wherein the epitope is SEQ ID NO: 5.