Method for down-regulating GDF-8 activity using immunogenic GDF-8 analogues

A GDF-8 analogue comprising a GDF-8 polypeptide that has been modified by at least one modification selected from the group consisting of

• substituting a first amino acid sequence in SEQ ID NO:
• 11 or 12 with a second amino acid sequence which comprises a foreign TH epitope, wherein said first amino acid sequence is from one or more of residues 1–12, 18–41, 40–48, 49–69 or 79–104 in SEQ ID NO:
• 11 or 12;
• inserting at least one amino acid sequence which comprises a foreign TH epitope at one or more of residues 1–12, 18–30, 42–51, 82–86 or 105–109 in SEQ ID NO:
• 11 or 12,
• substituting a first amino acid sequence in SEQ ID NO:
• 11 or 12 with a second amino acid sequence which comprises a foreign TH epitope, wherein said first amino acid sequence is a loop area or a flexible terminus in the GDF-8 polypeptide comprising SEQ ID NO:11 or 12;
• and
• inserting at least one amino acid sequence which comprises a foreign TH epitope into a loop areas or in a flexible terminus in the GDF-8 polypeptide comprising SEQ ID NO:
• 11 or 12;
• wherein the number of amino acid insertions and substitutions does not exceed 60.