When designing synthetic peptides for diagnostics or vaccines, several sequence-level suggestions apply:

• Avoid extensive stretches of strongly nonpolar (hydrophobic) amino acids.
• Remember that some epitopes serve a dual B-cell and T-cell epitope role.
• Avoid N-terminal asparagine (N) or glutamine (Q), and C-terminal proline (P) or glycine (G).

Potential concerns to address include:

• Lack of biostability (susceptibility to proteolysis).
• Whether the peptide can raise antibodies.
• Implanting immune-system memory in the case of vaccines.
• Specificity, i.e., avoiding unwanted cross-reactions with other proteins whose epitopes are similar to the target protein of interest.