title: Characterization of preexisting MAGE-A3-specific CD4+ T cells in cancer patients and healthy individuals and their activation by protein vaccination.
abstract: Vaccination with cancer/testis Ag MAGE-A3 in the form of recombinant protein often induces specific humoral and cellular immune responses. Although Ag-specific CD4+ T cells following vaccination are detectable by cytokine production after a single in vitro stimulation, their detection before vaccination is difficult because of low frequency. In this study, we have applied a sensitive method using CD154 (CD40L) staining to detect MAGE-A3-specific CD4+ T cells. MAGE-A3-specific T cell responses were analyzed in four healthy donors, two lung cancer patients with spontaneous serum Abs to MAGE-A3, and two baseline seronegative lung cancer patients throughout vaccination with MAGE-A3 protein. MAGE-A3-specific CD4+ T cells were detected in all individuals tested, at low frequency in healthy donors and seronegative cancer patients and higher frequency in patients seropositive for MAGE-A3. Polyclonal expansion of CD154-expressing CD4+ T cells after cell sorting generated a large number of MAGE-A3-specific CD4+ T cell lines from all individuals tested, enabling full characterization of peptide specificity, HLA-restriction, and avidity. Application of this method to cancer patients vaccinated with MAGE-A3 protein with or without adjuvant revealed that protein vaccination induced oligoclonal activation of MAGE-A3-specific CD4+ T cells. It appeared that MAGE-A3 protein vaccination in the presence of adjuvant selectively expanded high avidity CD4+ T cells, whereas high avidity T cells disappeared after multiple vaccinations with MAGE-A3 protein alone.
authors.affiliation: Ludwig Institute for Cancer Research, New York Branch at Memorial Sloan-Kettering Cancer Center, New York, NY 10065, USA.
authors.forename: Takemasa
authors.initials: T
authors.lastname: Tsuji
authors.forename: Nasser K
authors.initials: NK
authors.lastname: Altorki
authors.forename: Gerd
authors.initials: G
authors.lastname: Ritter
authors.forename: Lloyd J
authors.initials: LJ
authors.lastname: Old
authors.forename: Sacha
authors.initials: S
authors.lastname: Gnjatic
mesh_terms: D000276:Adjuvants, Immunologic / Q000008:administration & dosage; D000951:Antigens, Neoplasm / Q000276:immunology*; D018791:CD4 Lymphocyte Count; D015496:CD4-Positive T-Lymphocytes / Q000166:cytology / Q000276:immunology* / Q000473:pathology; D019496:Cancer Vaccines / Q000008:administration & dosage / Q000276:immunology*; D002289:Carcinoma, Non-Small-Cell Lung / Q000276:immunology / Q000473:pathology / Q000628:therapy; D002461:Cell Line, Transformed; D018920:Coculture Techniques; D018984:Epitopes, T-Lymphocyte / Q000276:immunology*; D006801:Humans; D007117:Immunization, Secondary; D008175:Lung Neoplasms / Q000276:immunology / Q000473:pathology / Q000628:therapy; D008213:Lymphocyte Activation / Q000276:immunology*; D009363:Neoplasm Proteins / Q000276:immunology*; D013997:Time Factors; D014407:Tumor Cells, Cultured; D022223:Vaccines, Subunit / Q000008:administration & dosage / Q000276:immunology*
chemical_list: D000276:Adjuvants, Immunologic; D000951:Antigens, Neoplasm; D019496:Cancer Vaccines; D018984:Epitopes, T-Lymphocyte; C072013:MAGEA3 protein, human; D009363:Neoplasm Proteins; D022223:Vaccines, Subunit