VMC 221: Veterinary Immunology and Serology (1+1)

PEPTIDE VACCINES

• Once the immunogenic sites of an organism are identified, immunogenic peptides can be synthesized or can be purified from natural sources.
• Several methods have been used to prepare it.
• Synthetic peptide vaccines would have many advantages. Their antigens are precisely defined and free from unnecessary components which may be associated with side effects.
• They are stable and relatively cheap to manufacture.
• Example, foot and mouth disease peptide vaccine where protection was achieved by immunizing animals with a linear sequence of 20 amino acids (141 to 160) of VP1.
• Synthetic peptides do not readily stimulate T cells and require coupling to a protein carrier which is recognized by T-cells.
• Advantages
  • Avoids use of whole organism
  • Side effects due to undesired part of the organism is reduced
  • Small enough to fit into most the antigen delivery vehicles 
  • Quite stable
• Disadvantages
  • May be perceived as haptens if not conjugated to carriers
  • Rapidly dissipated in tissues, thus requires highly effective adjuvants or effective delivery vehicles.
  • May be costly or difficult to identify and purify.