Peptide Vaccine
A vaccine using synthetic peptide fragments (epitopes) to stimulate an immune response against specific disease targets. Peptide vaccines can target cancer, infectious diseases, or autoimmune conditions. They represent a distinct application of peptide science separate from therapeutic peptide drugs.
Technical Context
Peptide vaccines use short synthetic peptide sequences (epitopes) that represent fragments of target antigens — typically 8-11 amino acids for MHC class I presentation (CD8+ cytotoxic T cell response) or 13-25 amino acids for MHC class II presentation (CD4+ helper T cell response). Applications: cancer immunotherapy (tumour-associated antigen peptides to prime anti-tumour immunity), infectious disease (pathogen-derived epitopes), and autoimmune disease (tolerogenic peptides to induce immune tolerance). Advantages: precise targeting of immune response, synthetic manufacturing (consistent quality, rapid production), and safety (no risk of reversion to virulence). Limitations: HLA restriction (individual MHC genotype determines which peptides are presented — a single epitope won't work for all patients), weak immunogenicity (short peptides are poorly immunogenic alone, requiring adjuvants and delivery systems), and immune evasion (tumours/pathogens may lose the targeted epitope).