title: Comparative ability of Qdm/Qa-1b, kb, and Db to protect class Ilow cells from NK-mediated lysis in vivo.
abstract: The class Ib molecule Qa-1(b) binds the class Ia leader peptide, Qdm, which reacts with CD94/NKG2R on NK cells. We have generated a gene that encodes the Qdm peptide covalently attached to ss(2)-microglobulin (ss(2)M) by a flexible linker (Qa-1 determinant modifier (Qdm)-ss(2)M). When this construct is expressed in TAP-2(-) or ss(2)M(-) cells, it allows for the expression of a Qdm-ss(2)M protein that associates with Qa-1(b) to generate the Qdm epitope, as detected by Qdm/Qa-1(b)-specific CTL. To test the biological significance of expression of this engineered molecule, we injected TAP-2(-) RMAS-Qdm-ss(2)M cells into C57BL/6 mice and measured their NK cell-mediated clearance from the lungs at 2 h. RMAS cells transfected with Qdm-ss(2)M were resistant to lung clearance, similar to RMA cells or RMAS cells in anti-asialo-GM(1)-treated mice, while untransfected or ss(2)M-transfected RMAS cells were rapidly cleared. Further, pulsing RMAS cells with either Qdm, a K(b)-, or D(b)-binding peptide showed equivalent protection from clearance, indicating that a single class Ia or Ib molecule can afford complete protection from NK cells in this system. In contrast, injection of RMAS cells into DBA/2 animals, which express low levels of receptors for Qdm/Qa-1(b), resulted in protection from lung clearance if pulsed with a K(b)- or D(b)-binding peptide, but not the Qa-1(b)-binding peptide, Qdm.
authors.affiliation: Center for Immunology, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA.
authors.forename: S H
authors.initials: SH
authors.lastname: Jia
authors.forename: Z
authors.initials: Z
authors.lastname: Kurepa
authors.forename: A
authors.initials: A
authors.lastname: Bai
authors.forename: J
authors.initials: J
authors.lastname: Forman
mesh_terms: D000818:Animals; D015415:Biomarkers; D002462:Cell Membrane / Q000235:genetics / Q000276:immunology / Q000378:metabolism; D003601:Cytotoxicity Tests, Immunologic; D003602:Cytotoxicity, Immunologic / Q000276:immunology*; D005786:Gene Expression Regulation / Q000276:immunology; D005822:Genetic Vectors / Q000138:chemical synthesis; D006183:H-2 Antigens / Q000096:biosynthesis / Q000276:immunology*; D064532:Histocompatibility Antigen H-2D; D015395:Histocompatibility Antigens Class I / Q000096:biosynthesis* / Q000235:genetics / Q000276:immunology* / Q000378:metabolism; D006801:Humans; D007694:Killer Cells, Natural / Q000276:immunology* / Q000378:metabolism; D051379:Mice; D008807:Mice, Inbred BALB C; D008810:Mice, Inbred C57BL; D008811:Mice, Inbred DBA; D010455:Peptides / Q000235:genetics / Q000378:metabolism; D011971:Receptors, Immunologic / Q000096:biosynthesis; D054340:Receptors, KIR; D014162:Transfection; D014407:Tumor Cells, Cultured / Q000276:immunology / Q000378:metabolism; D001613:beta 2-Microglobulin / Q000096:biosynthesis / Q000138:chemical synthesis / Q000235:genetics / Q000378:metabolism
chemical_list: D015415:Biomarkers; D006183:H-2 Antigens; C032876:H-2Kb protein, mouse; D064532:Histocompatibility Antigen H-2D; D015395:Histocompatibility Antigens Class I; D010455:Peptides; C032907:Q surface antigens; D011971:Receptors, Immunologic; D054340:Receptors, KIR; D001613:beta 2-Microglobulin