Starting with 10-or 11-mers peptides, results show that the method has difficulties navigating to different peptide lengths and does not show greater preference for 9-mers peptides (Fig. ). Unsurprisingly, with an initial batch composed of 9-mers, BO keeps prioritizing 9-mers peptides over other peptide lengths (Fig. ). Conversely, starting from an initial batch of 8-mers, BO seems to be able to explore different peptide lengths, and is even able to identify 9-mers as the optimal sequence lengths using predictions from the structure-based method (Rosetta Flex ∆∆G) after two DMT cycles (Fig. ). Moreover, a large performance gap is observed between the initialization strategies employed. A sharper decrease is observed using the homolog scanning strategy compared to the structure-based method. However, it is important to highlight the fact that the probability to generate by chance a 9-, 10-or 11-mers peptide with a better pIC50 than a 8-mers peptide is non-negligible (Fig. and, black lines). This makes these observations likely to be fortuitous, wrongly suggesting that the method is able to extrapolate binding of MHC class I peptides with different lengths, starting from 8-mers peptides, for which the opposite was shown earlier with 10-or 11-mers peptides.