Characterization of the peptide-binding specificity of Mamu-B*17 and identification of Mamu-B*17-restricted epitopes derived from simian immunodeficiency virus proteins.
The SIV-infected rhesus macaque is an excellent model to examine candidate AIDS virus vaccines. These vaccines should elicit strong CD8(+) responses. Previous definition of the peptide-binding motif and optimal peptides for Mamu-A*01 has created a demand for Mamu-A*01-positive animals. We have now studied a second MHC class I molecule, Mamu-B*17, that is present in 12% of captive-bred Indian rhesus macaques. The peptide-binding specificity of the Mamu-B*17 molecule was characterized using single substitution analogs of two Mamu-B*17-binding peptides and libraries of naturally occurring sequences of viral or bacterial origin. Mamu-B*17 uses position 2 and the C terminus of its peptide ligands as dominant anchor residues. The C terminus was found to have a very narrow specificity for the bulky aromatic residue W, with other aromatic residues (F and Y) being only occasionally tolerated. Position 2 is associated with a broad chemical specificity, readily accommodating basic (H and R), bulky hydrophobic (F and M), and small aliphatic (A) residues. Using this motif, we identified 50 peptides derived from SIV(mac)239 that bound Mamu-B*17 with an affinity of 500 nM or better. ELISPOT and intracellular cytokine-staining assays showed that 16 of these peptides were antigenic. We have, therefore, doubled the number of MHC class I molecules for which SIV-derived binding peptides have been characterized. This allows for the quantitation of immune responses through tetramers and analysis of CD8(+) function by intracellular cytokine-staining assays and ELISPOT. Furthermore, it is an important step toward the design of a multiepitope vaccine for SIV and HIV.
Mothé
Bianca R
BR
Wisconsin Regional Primate Research Center, University of Wisconsin, Madison, WI 53715, USA.
Sidney
John
J
Dzuris
John L
JL
Liebl
Max E
ME
Fuenger
Sarah
S
Watkins
David I
DI
Sette
Alessandro
A
D019943:Amino Acid Substitution; D000818:Animals; D018984:Epitopes, T-Lymphocyte / Q000737:chemistry / Q000378:metabolism*; D015395:Histocompatibility Antigens Class I / Q000737:chemistry / Q000378:metabolism*; D008024:Ligands; D008253:Macaca mulatta / Q000276:immunology*; D010446:Peptide Fragments / Q000737:chemistry / Q000276:immunology* / Q000378:metabolism*; D019151:Peptide Library; D011485:Protein Binding / Q000276:immunology; D016097:Simian Acquired Immunodeficiency Syndrome / Q000276:immunology / Q000378:metabolism; D015302:Simian Immunodeficiency Virus / Q000276:immunology*; D013602:T-Lymphocytes, Cytotoxic / Q000276:immunology / Q000378:metabolism; D054334:Viral Regulatory and Accessory Proteins / Q000737:chemistry / Q000276:immunology / Q000378:metabolism*
D018984:Epitopes, T-Lymphocyte; D015395:Histocompatibility Antigens Class I; D008024:Ligands; D010446:Peptide Fragments; D019151:Peptide Library; D054334:Viral Regulatory and Accessory Proteins