title: Molecular mimicry of MAGE-A6 andMycoplasma penetransHF-2 epitopes in the induction of antitumor CD8+T-cell responses.
abstract: A promising vaccine strategy for the treatment of cancer involves the use of vaccines incorporating tumor antigen-derived synthetic peptides that can be coordinately recognized by specific CD4+and CD8+T-cells. Previously, we reported that a MAGE-A6-derived peptide (MAGE-A6172-187) and its highly-immunogenic and cross-reactive homolog derived fromMycoplasma penetransHF-2 permease (HF-2216-229) are promiscuously presented by multiple HLA-DR alleles to responder CD4+T-cells obtained from healthy donors and melanoma patients. Here, we investigated whether these same peptides could concomitantly stimulate cross-reactive MAGE-A6-specific CD8+T-cell responsesin vitrousing cells isolated from HLA-A*0201 (HLA-A2)+healthy individuals and patients with melanoma. We now show that MAGE-A6172-187and, even more so, HF-2216-229, induce memory CD8+T cells that recognize HLA-A2+MAGE-A6+tumor target cells. The immunogenicity of these peptides was at least partially attributed to their embedded MAGE-A6176-185and HF-2220-229"homologous" sequences. The functional avidity of HF-2216-229peptide-primed CD8+T cells for the MAGE-A6172-187peptide was more than 100-fold greater than that of CD8+T cells primed with the corresponding MAGE-A6 peptide. Additionally, these 2 peptides were recognized in interferon γ (IFNγ) and granzyme B ELISPOT assays by CD8+T-cell clones displaying variable T-cell receptor (TCR) Vβ usage. These data suggest that the immune cross-reactivity of the MAGE-A6172-187and HF-2216-229peptides extends to CD8+T cells, at least in HLA-A2+donors, and supports the potential translational utility of these epitopes in clinical vaccine formulations and for immunomonitoring of cancer patients.
authors.affiliation: University of Pittsburgh Cancer Institute ; Pittsburgh, PA USA ; University of Pittsburgh School of Medicine; Department of Medicine ; Pittsburgh, PA USA.
authors.forename: Lazar
authors.initials: L
authors.lastname: Vujanovic
authors.affiliation: University of Pittsburgh Cancer Institute ; Pittsburgh, PA USA ; University of Pittsburgh School of Medicine; Department of Medicine ; Pittsburgh, PA USA.
authors.forename: Jian
authors.initials: J
authors.lastname: Shi
authors.affiliation: University of Pittsburgh Cancer Institute ; Pittsburgh, PA USA ; University of Pittsburgh School of Medicine; Department of Medicine ; Pittsburgh, PA USA.
authors.forename: John M
authors.initials: JM
authors.lastname: Kirkwood
authors.affiliation: University of Pittsburgh Cancer Institute ; Pittsburgh, PA USA ; University of Pittsburgh School of Medicine; Department of Immunology ; Pittsburgh, PA USA ; University of Pittsburgh School of Medicine; Department of Dermatology ; Pittsburgh, PA USA.
authors.forename: Walter J
authors.initials: WJ
authors.lastname: Storkus
authors.affiliation: University of Pittsburgh Cancer Institute ; Pittsburgh, PA USA ; University of Pittsburgh School of Medicine; Department of Medicine ; Pittsburgh, PA USA ; University of Pittsburgh School of Medicine; Department of Immunology ; Pittsburgh, PA USA ; University of Pittsburgh School of Medicine; Department of Surgery ; Pittsburgh, PA USA.
authors.forename: Lisa H
authors.initials: LH
authors.lastname: Butterfield
keywords: APC, antigen presenting cell; AdV, recombinant adenoviral vector; CD8+ T-cell; CTL, cytotoxic T lymphocyte; EBV, Epstein-Barr virus; FBS, fetal bovine serum; HD, healthy donor; HLA, human leukocyte antigen; HPLC, high-performance liquid chromatography; IVS, in vitro stimulation; MACS, Magnetic-Activated Cell Sorting; MAGE-A6; MOI, multiplicity of infection; Mycoplasma penetrans; PBMC, peripheral blood mononuclear cell; PFU, plaque forming units; RT-PCR, reverse transcription polymerase chain reaction; TAA, tumor associated antigen; TCM, T cell media; TCR, T-cell receptor; epitope mimic; iDC, immature dendritic cells; mDC, mature dendritic cells; melanoma