Figure 6.

Sequence-based approach reveals promiscuity of MHC class II-binding microbial peptides. IEDB analysis server allows the prediction of HLA binders using sequence-based algorithmic tool for peptides ≥15 mer. The microbial peptide was fragmented into overlapping 15-mer residues and each fragment was predicted for their binding affinity across MHC class II molecules. The score of each fragment was classified based on predicted IC₅₀ value as strong binders (IC₅₀ ≤ 50), weak binders (50 < IC₅₀ ≤ 500) and non-binders (IC₅₀ > 500). Based on their IC₅₀ values, the peptides are ranked into percentile score for each overlapping fragment. Average percentile score for each fragment represents the overall affinity of the full-length peptide. Low percentile score (≤25) were considered to be HLA class II binders.