OVA is a model antigen extensively studied
Proteolytic processing of proteins in the cytoplasm generates peptide epitopes that are generally 8-10 amino acids in length. The binding of these peptides to the surface major histocompatibility complex (MHC) class I molecules and subsequent presentation to T-cells elicits an immune response.1
A model antigen extensively studied is Ovalbumin (OVA). OVA is processed to the presenting octapeptide (257-264), SIINFEKL, through proteasomal and non-proteasomal activities.2 As with peptides naturally presented by H-2Kb, SIINFEKL has on its 5th position an amino acid with an aromatic side chain (Phe) and on the 8th position, an aliphatic side chain (Leu).3 Variants of this peptide consisting of substituting different amino acids at strategic positions have yielded valuable information on the interaction of this peptide and the MHC complex.3
1. Heemel, M & H. Ploegh Annu. Rev. Biochem. 64, 463 (1995).
2. Beninga, J. et al. J. Biol. Chem. 273, 18734 (1998).
3. Hin, S. et al. J. Biol. Chem. 276, 48790 (2001).