One aspect of the invention relates to a peptide comprising the amino acid sequence of formula (I), ENPVVHFFK91NIVTP96RTP (I)  (SEQ ID NO: 3) wherein at least one of K91 and P96 is substituted by a natural or unnatural amino acid, wherein said peptide is in linear or cyclic form. Another aspect of the invention relates to a peptide comprising the amino acid sequence of formula (Ia), ENPVVHFFK91NIVT96RTP (Ia), (SEQ ID NO: 4) wherein each of K91 and P96 is substituted by a natural or unnatural amino acid. Another aspect of the invention relates to a peptide comprising the amino acid sequence of formula (Ib), ENPVVHFFK91NIVT96RTP (Ib) (SEQ ID NO: 5) wherein at least one of K91 and P96 is substituted by an amino acid selected from R, E, F and Y. Yet another aspect of the invention relates to a peptide comprising the amino acid sequence of formula (II), VHFFK91NIVT96RTP (II) (SEQ ID NOS: 7 and 8) wherein K91 is substituted by the amino acid A and P96 is substituted by the amino acid A, wherein said peptide is in linear or cyclic form. Further aspects of the invention relate to conjugates of the above described peptides with mannan, pharmaceutical compositions and methods of treating autoimmune disorders.