1. The antigenicity was calculated as proposed by Kolaskar et al. [9] . The frequency of the residue in antigenic determinants (experimentally identified) was exploited to calculate the antigenic propensity of each amino acid. 2. The accessibility was calculated on the basis of the scale proposed by Janin et al. [10] . The importance of the accessibility information is widely reported in the literature; the hypothesis is that an accessible site is likely to be recognized by the antibodies [25, [30] [31] [32] . 3. The hydrophilicity was computed following the scale proposed by Parker et al. [11] . This scale was recently found to have slightly better results than the other ones [2, 33] . The hypothesis for hydrophilicity is that the antigenic sites are on the surface, so they are probably hydrophilic [5, 11] . 4. The flexibility was calculated with the scale proposed by Bhaskaran et al. [12] . A high flexibility of the structure is hypothesized to favor the propensity of a peptide to bind the antibodies [34] [35] . 5. The beta-turn prediction was calculated by exploiting an amino acid scale of propensities following the Chou-Fasman method [2, 8, 13 ].