title: Amino-terminal extended peptide single-chain trimers are potent synthetic agonists for memory human CD8+ T cells.
abstract: Upon Ag exposure, most memory T cells undergo restimulation-induced cell death. In this article, we describe a novel synthetic agonist, an N-terminal extended decamer peptide expressed as a single-chain trimer, the amino-terminal extended peptide MHC class I single-chain trimer (AT-SCT), which preferentially promotes the growth of memory human CD8(+) T cells with minimal restimulation-induced cell death. Using CMV pp65 and melanoma gp100 Ags, we observe the in vitro numerical expansion of a clonally diverse polyfunctional population of Ag-specific CD8(+) T cells from healthy individuals and vaccinated melanoma patients, respectively. Memory CD8(+) T cells stimulated with AT-SCT presented on MHC class I/II-null cells show reduced cytokine production, slower kinetics of TCR downregulation, and decreased cell death compared with native nonamer MHC class I single-chain trimer (SCT)-activated T cells. However, both ERK phosphorylation and cell cycle kinetics are identical in AT-SCT- and SCT-activated T cells. Probing of SCT and AT-SCT peptide-MHC complexes using fluorochrome-conjugated TCR multimers suggests that nonamer- and decamer-linked peptides may be anchored differently to the HLA-A2 peptide-binding groove. Our findings demonstrate that modified peptide-MHC structures, such as AT-SCT, can be engineered as T cell agonists to promote the growth and expansion of memory human CD8(+) T cells.
authors.affiliation: Division of Oncology, Department of Medicine, Washington University School of Medicine, St. Louis, MO 63110, USA. bcarreno@dom.wustl.edu
authors.forename: Beatriz M
authors.initials: BM
authors.lastname: Carreno
authors.forename: Michelle
authors.initials: M
authors.lastname: Becker-Hapak
authors.forename: Megan
authors.initials: M
authors.lastname: Chan
authors.forename: Wen-Rong
authors.initials: WR
authors.lastname: Lie
authors.forename: Xiaoli
authors.initials: X
authors.lastname: Wang
authors.forename: Ted H
authors.initials: TH
authors.lastname: Hansen
authors.forename: Gerald P
authors.initials: GP
authors.lastname: Linette
mesh_terms: D017209:Apoptosis / Q000276:immunology; D018414:CD8-Positive T-Lymphocytes / Q000276:immunology*; D049109:Cell Proliferation; D016207:Cytokines / Q000096:biosynthesis; D005434:Flow Cytometry; D015789:HLA-A2 Antigen / Q000276:immunology*; D006801:Humans; D007156:Immunologic Memory / Q000276:immunology*; D008213:Lymphocyte Activation / Q000276:immunology*; D010446:Peptide Fragments / Q000276:immunology*; D011993:Recombinant Fusion Proteins / Q000276:immunology
chemical_list: D016207:Cytokines; D015789:HLA-A2 Antigen; D010446:Peptide Fragments; D011993:Recombinant Fusion Proteins