595387 Disclosed are peptide derived from antibodies with reactivity against a GPI linkage epitope, wherein the peptide consists of an amino acid sequence selected from: Q-Q-x-x-x-x-P-x-x ; Q-Q-x-x-S-x-P-x-T ; and Q-Q-x-N-x-x-P-x-x . Also disclosed are methods of expressing said peptide, vaccine compositions comprising said peptide, and the use of said peptide in the production of a medicament for treating diseases such as autoimmune diseases, cardiovascular diseases, glucose intolerance, etc.