title: Rapid high efficiency sensitization of CD8+ T cells to tumor antigens by dendritic cells leads to enhanced functional avidity and direct tumor recognition through an IL-12-dependent mechanism.
abstract: Myeloid-origin dendritic cells (DCs) can develop into IL-12-secreting DC1 or non-IL-12-secreting DC2 depending on signals received during maturation. Through rapid culture techniques that prepared either mature, CD83+ DC1 or DC2 from CD14+ monocytes in only 2 days followed by a single 6-7 day DC-T cell coculture, we sensitized normal donor CD8+ T cells to tumor Ags (HER-2/neu, MART-1, and gp100) such that peptide Ag-specific lymphocytes constituted up to 16% of the total CD8+ population. Both DC1 and DC2 could sensitize CD8+ T cells that recognized peptide-pulsed target cells. However, with DC2, a general decoupling was observed between recognition of peptide-pulsed T2 target cells and recognition of Ag-expressing tumor cells, with peptide-sensitized T cells responding to tumor only about 15% of the time. In contrast, direct recognition of tumor by T cells was dramatically increased (to 85%) when DC1 were used for sensitization. Enhanced tumor recognition was accompanied by 10- to 100-fold increases in peptide sensitivity and elevated expression of CD8beta, characteristic of high functional avidity T cells. Both of these properties were IL-12-dependent. These results demonstrate the utility of rapid DC culture methods for high efficiency in vitro T cell sensitization that achieves robust priming and expansion of Ag-specific populations in 6 days. They also demonstrate a novel function of IL-12, which is enhancement of CD8+ T cell functional avidity. A new approach to DC-based vaccines that emphasizes IL-12 secretion to enhance functional avidity and concomitant tumor recognition by CD8+ T cells is indicated.
authors.affiliation: Harrison Department of Surgical Research, Department of Surgery, University of Pennsylvania, 3400 Spruce Street, Philadelphia, PA 19104, USA.
authors.forename: Shuwen
authors.initials: S
authors.lastname: Xu
authors.forename: Gary K
authors.initials: GK
authors.lastname: Koski
authors.forename: Mark
authors.initials: M
authors.lastname: Faries
authors.forename: Isabelle
authors.initials: I
authors.lastname: Bedrosian
authors.forename: Rosemarie
authors.initials: R
authors.lastname: Mick
authors.forename: Markus
authors.initials: M
authors.lastname: Maeurer
authors.forename: Martin A
authors.initials: MA
authors.lastname: Cheever
authors.forename: Peter A
authors.initials: PA
authors.lastname: Cohen
authors.forename: Brian J
authors.initials: BJ
authors.lastname: Czerniecki
mesh_terms: D000276:Adjuvants, Immunologic / Q000502:physiology; D000328:Adult; D017951:Antigen Presentation; D000951:Antigens, Neoplasm / Q000276:immunology* / Q000378:metabolism; D016827:CD8 Antigens / Q000096:biosynthesis; D018414:CD8-Positive T-Lymphocytes / Q000166:cytology / Q000276:immunology* / Q000378:metabolism; D002448:Cell Adhesion / Q000276:immunology; D002454:Cell Differentiation / Q000276:immunology; D045744:Cell Line, Tumor; D002478:Cells, Cultured; D017077:Culture Media, Conditioned / Q000494:pharmacology; D003602:Cytotoxicity, Immunologic / Q000276:immunology; D003713:Dendritic Cells / Q000145:classification / Q000166:cytology / Q000276:immunology*; D018984:Epitopes, T-Lymphocyte / Q000276:immunology; D005260:Female; D006801:Humans; D007114:Immunization / Q000379:methods; D018664:Interleukin-12 / Q000502:physiology*; D008213:Lymphocyte Activation / Q000276:immunology; D058965:MART-1 Antigen; D008297:Male; D008545:Melanoma / Q000276:immunology* / Q000378:metabolism; D008562:Membrane Glycoproteins / Q000276:immunology / Q000378:metabolism; D009363:Neoplasm Proteins / Q000276:immunology / Q000378:metabolism; D010446:Peptide Fragments / Q000276:immunology / Q000378:metabolism; D018719:Erb-b2 Receptor Tyrosine Kinases / Q000276:immunology / Q000378:metabolism; D016176:T-Lymphocyte Subsets / Q000166:cytology / Q000276:immunology / Q000378:metabolism; D058951:gp100 Melanoma Antigen
chemical_list: D000276:Adjuvants, Immunologic; D000951:Antigens, Neoplasm; D016827:CD8 Antigens; D017077:Culture Media, Conditioned; D018984:Epitopes, T-Lymphocyte; D018664:Interleukin-12; D058965:MART-1 Antigen; D008562:Membrane Glycoproteins; D009363:Neoplasm Proteins; D010446:Peptide Fragments; D018719:Erb-b2 Receptor Tyrosine Kinases; D058951:gp100 Melanoma Antigen; C477867:CD8beta antigen; C548667:MLANA protein, human; C548637:PMEL protein, human