Convergent combinatory peptide libraries and their use for vaccination against hepatitis c virus

Process for preparing immunogenic peptides corresponding to restricted regions of virus proteins involving a T cell immune response and to convergent combinatory peptide libraries derived from, said regions, characterized in that it includes:

• a) identifying sequences of amino acids constituting potential T epitopes, by predictive, non-experimental searching—for anchoring motifs for class II MHC molecules, from the native sequences of the proteins of the virus—and for areas having a high density of said anchoring motifs;
• b) designing convergent combinatory peptide libraries (termed “convertopes”), derived from the sequences of epitopes identified in a), by targeted substitution of amino acids at chosen positions, to induce non-natural degeneracy of each of the epitopes,
• on one hand, in order to increase the ability of the epitope to anchor to the class II MHC molecules,
• and, on the other hand, in order to broaden the repertory of recognition of the epitope by the T cell receptor;
• c) synthesizing
• on one hand, the peptides with native sequence chosen among the peptides as identified in a),
• and, on the other hand, the corresponding convertopes as identified in b).