Identification of a novel HLA-B60-restricted T cell epitope of the minor histocompatibility antigen HA-1 locus.
The polymorphic minor histocompatibility Ag HA-1 locus encodes two peptides, HA-1(H) and HA-1(R), with a single amino acid difference. Whereas the immunogenicity of the HA-1(R) allele has not yet been shown, the nonameric HA-1(H) peptide induces HLA-A2-restricted cytotoxic T cells in vivo and in vitro. It is not known whether the mHag HA-1(H) or HA-1(R) associates with other HLA class I molecules. Therefore, the polymorphic regions of both HA-1 alleles were analyzed to identify HLA class I binding peptides that are properly processed by proteasomal degradation. Peptide binding analyses were performed for all nonameric HA-1(H/R) peptides for binding to nine HLA class I molecules with >10% prevalence in the Caucasian population and for seven nonameric/decameric HA-1(H/R) peptides predicted to bind to HLA-A3, -B14, and -B60. Only the nonameric KECVL(H)/(R)DDL and decameric KECVL(H)/(R)DDLL peptides showed strong and stable binding to HLA-B60. In vitro digestion of 29-aa-long HA-1 peptides by purified 20S proteasomes revealed proper cleavage at the COOH termini of both HLA-B60 binding HA-1(H) and HA-1(R) peptides. In subsequent analyses, dendritic cells pulsed with the nonameric HA-1(R) peptide did not induce CTLs that recognize the natural HLA-B60/HA-1(R) ligand. In contrast, dendritic cells pulsed with the nonameric HA-1(H) peptide induced IFN-gamma-secreting T cells specific for the natural HLA-B60/HA-1(H) ligand in three HLA-B60(+) HA-1(RR) individuals, demonstrating the immunogenicity of the HLA-B60/HA-1(H) ligand. In conclusion, this study shows a novel HLA-B60-restricted T cell epitope of the minor histocompatibility Ag HA-1 locus.
Mommaas
Bregje
B
Department of Immunohematology and Blood Transfusion, Leiden University Medical Center, Leiden, The Netherlands.
Kamp
Janine
J
Drijfhout
Jan-Wouter
JW
Beekman
Nico
N
Ossendorp
Ferry
F
Van Veelen
Peter
P
Den Haan
Joke
J
Goulmy
Els
E
Mutis
Tuna
T
D000595:Amino Acid Sequence; D001120:Arginine / Q000378:metabolism; D002460:Cell Line; D002478:Cells, Cultured; D003546:Cysteine Endopeptidases / Q000378:metabolism; D018984:Epitopes, T-Lymphocyte / Q000302:isolation & purification* / Q000378:metabolism*; D015235:HLA-B Antigens / Q000235:genetics / Q000378:metabolism*; D006639:Histidine / Q000378:metabolism; D006801:Humans; D006868:Hydrolysis; D008213:Lymphocyte Activation; D015778:Minor Histocompatibility Antigens / Q000302:isolation & purification* / Q000378:metabolism*; D008912:Minor Histocompatibility Loci; D008969:Molecular Sequence Data; D009097:Multienzyme Complexes / Q000378:metabolism; D009842:Oligopeptides / Q000138:chemical synthesis / Q000302:isolation & purification* / Q000378:metabolism*; D010446:Peptide Fragments / Q000378:metabolism; D046988:Proteasome Endopeptidase Complex; D011485:Protein Binding / Q000276:immunology; D014162:Transfection
D018984:Epitopes, T-Lymphocyte; C110615:HA-1 antigen; D015235:HLA-B Antigens; C081918:HLA-B60 antigen; D015778:Minor Histocompatibility Antigens; D009097:Multienzyme Complexes; D009842:Oligopeptides; D010446:Peptide Fragments; D006639:Histidine; D001120:Arginine; D003546:Cysteine Endopeptidases; D046988:Proteasome Endopeptidase Complex