title: Reduced recognition of metastatic melanoma cells by autologous MART-1 specific CTL: relationship to TAP expression.
abstract: Class I expression in context with T-cell receptor expression is crucial for peptide presentation and induction of CD8+ cytotoxic T lymphocytes (CTL). Presentation of class I bound peptides is dependent on transporter-associated proteins (TAP) expression and function. Tumor infiltrating lymphocytes from a patient with melanoma were isolated, expanded in vitro in the presence of interleukin-2, and tested for cytotoxicity against HLA-A2 positive, MART-1 positive autologous tumor cells, an HLA-A2-positive, MART-1 positive melanoma cell line (Mel-501), and HLA-A2-negative melanoma cells. Significant killing occurred against both A2-positive cell lines (63% and 65%, respectively), but not against the A2-negative line (18%) or A2-positive autologous tumor (1.5%). These CTL preferentially recognized the MART-1 peptide F119, 27-35, and gp100 peptide F125, 280-288, resulting in a 30% to 60% enhancement of lysis when autologous tumor or major histocompatibility complex class I "empty" T2 cells were pulsed with either peptide. To address whether the deficiency in autologous tumor recognition might be related to a deficiency in Ag presentation, we screened for the presence of TAP1 and TAP2 transcripts by polymerase chain reaction, Southern blotting, and scanning densitometry using sequence-specific primers and probes. Both TAP1 and TAP2 expression levels in the autologous tumor were minimal, yet were upregulated 7- to 18-fold, respectively, by interferon-gamma. Despite this increase, a similar increase in cytotoxicity did not occur. In short, deficiencies in TAP presentation may have functional significance for tumor escape from immunosurveillance and with respect to impending vaccine trials.
authors.affiliation: Department of Bioimmunotherapy, MD Anderson Cancer Center, Houston, Texas 77030, USA.
authors.forename: J L
authors.initials: JL
authors.lastname: Murray
authors.forename: J M
authors.initials: JM
authors.lastname: Hudson
authors.forename: M I
authors.initials: MI
authors.lastname: Ross
authors.forename: H Z
authors.initials: HZ
authors.lastname: Zhang
authors.forename: C G
authors.initials: CG
authors.lastname: Ioannides
mesh_terms: D000071181:ATP Binding Cassette Transporter, Subfamily B, Member 2; D000071450:ATP Binding Cassette Transporter, Subfamily B, Member 3; D018528:ATP-Binding Cassette Transporters / Q000235:genetics*; D000008:Abdominal Neoplasms / Q000276:immunology* / Q000556:secondary; D000951:Antigens, Neoplasm / Q000276:immunology*; D003602:Cytotoxicity, Immunologic; D005260:Female; D015870:Gene Expression; D015789:HLA-A2 Antigen / Q000276:immunology; D006801:Humans; D007371:Interferon-gamma / Q000276:immunology / Q000494:pharmacology; D016246:Lymphocytes, Tumor-Infiltrating / Q000276:immunology*; D058965:MART-1 Antigen; D008285:Major Histocompatibility Complex; D008545:Melanoma / Q000276:immunology* / Q000473:pathology / Q000556:secondary; D008875:Middle Aged; D009362:Neoplasm Metastasis; D009363:Neoplasm Proteins / Q000276:immunology*; D010455:Peptides / Q000276:immunology; D010641:Phenotype; D013602:T-Lymphocytes, Cytotoxic / Q000187:drug effects / Q000276:immunology*; D014407:Tumor Cells, Cultured
chemical_list: D000071181:ATP Binding Cassette Transporter, Subfamily B, Member 2; D000071450:ATP Binding Cassette Transporter, Subfamily B, Member 3; D018528:ATP-Binding Cassette Transporters; D000951:Antigens, Neoplasm; D015789:HLA-A2 Antigen; D058965:MART-1 Antigen; C548667:MLANA protein, human; D009363:Neoplasm Proteins; D010455:Peptides; C073119:TAP1 protein, human; C071692:TAP2 protein, human; D007371:Interferon-gamma