Overlapping peptide libraries are ideal for T-cell epitope identification because T cell epitopes are by their nature short linear peptides from the primary protein sequence. Overlapping peptide libraries are also appropriate for scanning the primary sequence of proteins for linear, or "continuous", B-cell (antibody-defined) epitopes.
The library generation process is defined by two parameters: peptide length and offset number which reflects the degree of overlap. The next to last peptide in each set (the 'orphan') is often shorter than the other peptides as it lies at the C-Terminus. The last peptide included in the set represents the orphan sequence plus one or more N-Terminal residues to bring it to the correct length.