title: MHC class II-mediated antigen presentation by melanoma cells.
abstract: Constitutive expression of major histocompatibility complex (MHC) class II molecules is normally restricted to professional antigen-presenting cells (APCs) of the immune system, although it also occurs frequently in melanoma. Clinical evidence suggesting that MHC class II expression by melanoma is associated with tumor progression led us to postulate a role for MHC class II-mediated antigen presentation in this disease. First, we investigated whether melanoma cells derived from metastases can process antigen and/or present peptide vi MHC class II molecules to a peptide-specific CD4+ T-cell clone. In all cell lines tested, melanoma cells were able to process antigen and present peptide efficiently to CD4+ T cells, resulting in T-cell proliferation increased 5-26-fold over controls. Next, we found that CD28-mediated costimulation was not required, because blocking with CTLA-4Ig had no effect on the T-cell response to either melanoma or B cells as APCs. In contrast, blocking CD54 (ICAM-1) resulted in a decrease in proliferation in response to peptide presentation by melanoma but not B cells. These data demonstrate that MHC class II molecules on melanoma cells are functional and that antigen-processing pathways are intact. In addition, CD54 seems to play a significant role in peptide presentation by melanoma.
authors.affiliation: Department of Surgery, Memorial Sloan-Kettering Cancer Center, New York 10021, USA.
authors.forename: M S
authors.initials: MS
authors.lastname: Brady
authors.forename: D D
authors.initials: DD
authors.lastname: Eckels
authors.forename: S Y
authors.initials: SY
authors.lastname: Ree
authors.forename: K E
authors.initials: KE
authors.lastname: Schultheiss
authors.forename: J S
authors.initials: JS
authors.lastname: Lee
mesh_terms: D000595:Amino Acid Sequence; D017951:Antigen Presentation; D000938:Antigen-Presenting Cells / Q000378:metabolism; D001402:B-Lymphocytes / Q000276:immunology; D018106:CD28 Antigens / Q000502:physiology; D015496:CD4-Positive T-Lymphocytes / Q000276:immunology / Q000378:metabolism; D000949:Histocompatibility Antigens Class II / Q000378:metabolism / Q000502:physiology*; D006801:Humans; D007108:Immune Tolerance; D008213:Lymphocyte Activation; D016169:Lymphocyte Function-Associated Antigen-1 / Q000502:physiology; D008545:Melanoma / Q000276:immunology*; D008969:Molecular Sequence Data; D010455:Peptides / Q000276:immunology / Q000378:metabolism; D012878:Skin Neoplasms / Q000276:immunology*; D014407:Tumor Cells, Cultured
chemical_list: D018106:CD28 Antigens; D000949:Histocompatibility Antigens Class II; D016169:Lymphocyte Function-Associated Antigen-1; D010455:Peptides