title: Photoaffinity antigens for human gammadelta T cells.
abstract: Vgamma2Vdelta2 T cells comprise the major subset of peripheral blood gammadelta T cells in humans and expand during infections by recognizing small nonpeptide prenyl pyrophosphates. These molecules include (E)-4-hydroxy-3-methyl-but-2-enyl-pyrophosphate (HMBPP), a microbial isoprenoid intermediate, and isopentenyl pyrophosphate, an endogenous isoprenoid intermediate. Recognition of these nonpeptide Ags is mediated by the Vgamma2Vdelta2 T cell Ag receptor. Several findings suggest that prenyl pyrophosphates are presented by an Ag-presenting molecule: contact between T cells and APC is required, the Ags do not bind the Vgamma2Vdelta2 TCR directly, and Ag recognition is abrogated by TCR mutations in CDRs distant from the putative Ag recognition site. Identification of the putative Ag-presenting molecule, however, has been hindered by the inability to achieve stable association of nonpeptide prenyl pyrophosphate Ags with the presenting molecule. In this study, we show that photoaffinity analogues of HMBPP, meta/para-benzophenone-(methylene)-prenyl pyrophosphates (m/p-BZ-(C)-C(5)-OPP), can crosslink to the surface of tumor cell lines and be presented as Ags to gammadelta T cells. Mutant tumor cell lines lacking MHC class I, MHC class II, beta(2)-microglobulin, and CD1, as well as tumor cell lines from a variety of tissues and individuals, will all crosslink to and present m-BZ-C(5)-OPP. Finally, pulsing of BZ-(C)-C(5)-OPP is inhibited by isopentenyl pyrophosphate and an inactive analog, suggesting that they bind to the same molecule. Taken together, these results suggest that nonpeptide Ags are presented by a novel-Ag-presenting molecule that is widely distributed and nonpolymorphic, but not classical MHC class I, MHC class II, or CD1.
authors.affiliation: Department of Internal Medicine, Division of Rheumatology, niversity of Iowa College of Medicine, Iowa City, IA 52242, USA.
authors.forename: Ghanashyam
authors.initials: G
authors.lastname: Sarikonda
authors.forename: Hong
authors.initials: H
authors.lastname: Wang
authors.forename: Kia-Joo
authors.initials: KJ
authors.lastname: Puan
authors.forename: Xiao-hui
authors.initials: XH
authors.lastname: Liu
authors.forename: Hoi K
authors.initials: HK
authors.lastname: Lee
authors.forename: Yongcheng
authors.initials: Y
authors.lastname: Song
authors.forename: Mark D
authors.initials: MD
authors.lastname: Distefano
authors.forename: Eric
authors.initials: E
authors.lastname: Oldfield
authors.forename: Glenn D
authors.initials: GD
authors.lastname: Prestwich
authors.forename: Craig T
authors.initials: CT
authors.lastname: Morita
mesh_terms: D017951:Antigen Presentation / Q000187:drug effects / Q000276:immunology*; D000938:Antigen-Presenting Cells / Q000276:immunology; D000941:Antigens / Q000737:chemistry / Q000276:immunology / Q000494:pharmacology*; D002461:Cell Line, Transformed; D045744:Cell Line, Tumor; D045782:Hemiterpenes / Q000737:chemistry / Q000276:immunology / Q000494:pharmacology*; D006649:Histocompatibility Antigens / Q000235:genetics / Q000276:immunology; D006801:Humans; D009154:Mutation; D010755:Organophosphates / Q000737:chemistry / Q000276:immunology / Q000494:pharmacology*; D009943:Organophosphorus Compounds / Q000737:chemistry / Q000276:immunology / Q000494:pharmacology*; D010777:Photochemistry; D016692:Receptors, Antigen, T-Cell, gamma-delta / Q000235:genetics / Q000276:immunology*; D013601:T-Lymphocytes / Q000276:immunology*
chemical_list: C467061:4-hydroxy-3-methyl-2-butenyl diphosphate; D000941:Antigens; D045782:Hemiterpenes; D006649:Histocompatibility Antigens; D010755:Organophosphates; D009943:Organophosphorus Compounds; D016692:Receptors, Antigen, T-Cell, gamma-delta; C004809:isopentenyl pyrophosphate