title: Ubiquitinated Proteins Isolated From Tumor Cells Are Efficient Substrates for Antigen Cross-Presentation.
abstract: We have previously shown that inhibition of the proteasome causes defective ribosomal products to be shunted into autophagosomes and subsequently released from tumor cells as defective ribosomal products in Blebs (DRibbles). These DRibbles serve as an excellent source of antigens for cross-priming of tumor-specific T cells. Here, we examine the role of ubiquitinated proteins (Ub-proteins) in this pathway. Using purified Ub-proteins from tumor cells that express endogenous tumor-associated antigen or exogenous viral antigen, we tested the ability of these proteins to stimulate antigen-specific T-cell responses, by activation of monocyte-derived dendritic cells generated from human peripheral blood mononuclear cells. Compared with total cell lysates, we found that purified Ub-proteins from both a gp100-specific melanoma cell line and from a lung cancer cell line expressing cytomegalovirus pp65 antigen produced a significantly higher level of IFN-γ in gp100- or pp65-specific T cells, respectively. In addition, Ub-proteins from an allogeneic tumor cell line could be used to stimulate tumor-infiltrating lymphocytes isolated and expanded from non-small cell lung cancer patients. These results establish that Ub-proteins provide a relevant source of antigens for cross-priming of antitumor immune responses in a variety of settings, including endogenous melanoma and exogenous viral antigen presentation, as well as antigen-specific tumor-infiltrating lymphocytes. Thus, ubiquitin can be used as an affinity tag to enrich for unknown tumor-specific antigens from tumor cell lysates to stimulate tumor-specific T cells ex vivo or to be used as vaccines to target short-lived proteins.
authors.affiliation: *School of Medicine, Southeast University, Nanjing, P.R. China †Robert W. Franz Cancer Research Center, Earle A. Chiles Research Institute, Providence Portland Medical Center, Portland, OR.
authors.forename: Guangjie
authors.initials: G
authors.lastname: Yu
authors.forename: Tarsem
authors.initials: T
authors.lastname: Moudgil
authors.forename: Zhihua
authors.initials: Z
authors.lastname: Cui
authors.forename: Yongbin
authors.initials: Y
authors.lastname: Mou
authors.forename: Lixin
authors.initials: L
authors.lastname: Wang
authors.forename: Bernard A
authors.initials: BA
authors.lastname: Fox
authors.forename: Hong-Ming
authors.initials: HM
authors.lastname: Hu
mesh_terms: D000276:Adjuvants, Immunologic; D000537:Aluminum Oxide / Q000276:immunology; D000951:Antigens, Neoplasm / Q000276:immunology; D001343:Autophagy; D019496:Cancer Vaccines / Q000276:immunology*; D002289:Carcinoma, Non-Small-Cell Lung / Q000276:immunology* / Q000628:therapy; D045744:Cell Line, Tumor; D045142:Cross-Priming; D003713:Dendritic Cells / Q000276:immunology*; D006801:Humans; D016219:Immunotherapy, Adoptive / Q000379:methods*; D007371:Interferon-gamma / Q000378:metabolism; D008175:Lung Neoplasms / Q000276:immunology* / Q000628:therapy; D008213:Lymphocyte Activation; D016246:Lymphocytes, Tumor-Infiltrating / Q000276:immunology* / Q000637:transplantation; D008545:Melanoma / Q000276:immunology* / Q000628:therapy; D010750:Phosphoproteins / Q000276:immunology; D012270:Ribosomes / Q000276:immunology; D013601:T-Lymphocytes / Q000276:immunology* / Q000637:transplantation; D057149:Ubiquitinated Proteins / Q000276:immunology; D014763:Viral Matrix Proteins / Q000276:immunology; D058951:gp100 Melanoma Antigen / Q000276:immunology
chemical_list: D000276:Adjuvants, Immunologic; D000951:Antigens, Neoplasm; D019496:Cancer Vaccines; D010750:Phosphoproteins; D057149:Ubiquitinated Proteins; D014763:Viral Matrix Proteins; C065418:cytomegalovirus matrix protein 65kDa; D058951:gp100 Melanoma Antigen; D007371:Interferon-gamma; D000537:Aluminum Oxide