Characterization of antigenic peptides presented by HLA-B44 molecules on tumor cells expressing the gene MAGE-3.
The amino acid sequence of the protein encoded by the gene MAGE-3 was screened for peptides containing the binding motif for HLA-B44. Nine peptides were synthesized, and their binding affinity for HLA-B*4402 and -B*4403 was analyzed in an HLA class I alpha-chain refolding assay. Four peptides with binding affinity for HLA-B*4403 were chosen for in vitro cytotoxic T-lymphocyte induction assays using as antigen-presenting cells peptide-pulsed, autologous activated B lymphoblasts from a healthy, B*4403+ donor. Peptide-specific effectors could be raised only against one peptide, M3-167. Cytotoxic T lymphocytes specific for this peptide were also able to recognize melanoma cell lines expressing HLA-B44 and the gene MAGE-3, strongly suggesting that M3-167 is a naturally processed MAGE-3-encoded epitope presented by HLA-B44. M3-167 is a I amino acid N-terminal extension of M3-168, a naturally processed epitope MAGE-3-encoded epitope presented by HLA-A1 that has been previously described. TAP binding studies of these 2 peptides revealed that the TAP affinity of M3-167 is about 9-fold higher than that of M3-168. M3-167 or a longer precursor could be transported into the endoplasmatic reticulum, where it could be trimmed for presentation by HLA-A1 or -B44 molecules. Taken together, our data suggest that M3-167 could be an immunodominant peptide encoded by the gene MAGE-3.
Fleischhauer
K
K
Gene Therapy Program, Department of Biology and Biotechnology (DIBIT), Istituto Scientifico H.S. Raffaele, Milano, Italy.
Fruci
D
D
Van Endert
P
P
Herman
J
J
Tanzarella
S
S
Wallny
H J
HJ
Coulie
P
P
Bordignon
C
C
Traversari
C
C
D000595:Amino Acid Sequence; D017951:Antigen Presentation; D000951:Antigens, Neoplasm; D015972:Gene Expression Regulation, Neoplastic; D015235:HLA-B Antigens / Q000235:genetics / Q000276:immunology*; D059948:HLA-B44 Antigen; D006801:Humans; D008969:Molecular Sequence Data; D009363:Neoplasm Proteins / Q000235:genetics* / Q000276:immunology; D010455:Peptides / Q000276:immunology; D014407:Tumor Cells, Cultured
D000951:Antigens, Neoplasm; D015235:HLA-B Antigens; D059948:HLA-B44 Antigen; C072013:MAGEA3 protein, human; D009363:Neoplasm Proteins; D010455:Peptides