Synthetic active peptide fragments

1) Method for constructing peptides on the basis of the three-dimensional structures of homologous molecules wherein said peptides are able to mimic or prevent the interaction between helminth pathogens and receptors, said method consisting of:

• (i) selecting regions of the parent protein which contain a high spatial density of residues which form continuous or discontinuous epitopes;
• (ii) give priority to maintaining the previously predicted epitopic residues, responsible for stimulating the desired immuno/antigenic response, within the selected peptide sequence;
• (iii) elaborate sequences which, whilst maintaining a high percentage of previously identified epitopic residues, are of limited size varying from 8 to 28 residues;
• (iv) two peptides may be chosen, which may correspond to regions which are distant in the primary structure (amino acid sequence) but spatially close in the tertiary (three-dimensional) structure, the said regions are chosen on the basis that the three-dimensional structure indicates that they can be readily united assuming that they retain their original structures.
• (v) modifications may be made to the peptide, be it derived from a single continuous stretch of amino acids or be it derived in the manner described in (iv), so as to favour the three-dimensional conformation as seen in the original protein, such modifications may include substitutions of amino acids as well as insertions or deletions of amino acids;
• (vi) residues may be used in order to restrict the conformational freedom of the final peptide.