Induction of transporter associated with antigen processing by interferon gamma confers endothelial cell cytoprotection against natural killer-mediated lysis.
T lymphocytes react minimally with nonactivated endothelial cells (ECs). However, natural killer (NK) lymphocyte interactions with resting ECs are rapid, avid, and result in endothelial activation and/or cytotoxicity. The molecular basis for these interactions and EC sensitivity to NK-mediated lysis is unclear. To address the EC-specific nature of NK sensitivity, we used syngeneic human umbilical vein ECs, dermal microvascular ECs, dermal fibroblasts, and B lymphoblastoid cell lines in calcein-AM retention NK assays with allogeneic NK effector cells and found the EC lines consistently more NK-sensitive. Because NK inhibitory receptors are engaged by membrane major histocompatibility complex (MHC) I molecules and MHC I-deficient targets are NK-sensitive, we investigated the quantitative levels of membrane MHC I on the panel of syngeneic lines. Highly sensitive ECs expressed similar (or higher) levels of membrane MHC I than their syngeneic NK-resistant counterparts. Pretreatment of ECs with gamma interferon (IFN-gamma) conferred protection against NK-mediated lysis, with much more rapid kinetics (2-6 hr) than those required for membrane MHC I hyperinduction (>8 hr). These kinetics are consistent with induction of transporter associated with antigen processing (TAP) expression and function. As opposed to NK-resistant cell lines, TAP-1 was undetectable in resting ECs. Recombinant expression of the TAP inactivator ICP47 by adenoviral-mediated transduction was used to selectively inhibit IFN-gamma-mediated EC TAP function. ICP47 expression abrogated EC cytoprotection conferred by IFN-gamma. We demonstrate a relationship between both basal and induced TAP-1 expression/function and EC sensitivity to NK-mediated cytotoxicity. We discuss the influence of an induced MHC I-associated peptide repertoire on vascular vulnerability to cytotoxic lymphocytes.
Ayalon
O
O
Division of Cardiovascular Medicine and Molecular Cardiobiology, Boyer Center for Molecular Medicine, The Raymond and Beverly Sackler Foundation Cardiobiology Laboratory, Yale University School of Medicine, New Haven, CT 06536-0812, USA.
Hughes
E A
EA
Cresswell
P
P
Lee
J
J
O'Donnell
L
L
Pardi
R
R
Bender
J R
JR
D001402:B-Lymphocytes / Q000276:immunology; D002352:Carrier Proteins / Q000096:biosynthesis*; D002462:Cell Membrane / Q000276:immunology; D002478:Cells, Cultured; D003602:Cytotoxicity, Immunologic; D004730:Endothelium, Vascular / Q000187:drug effects / Q000276:immunology*; D015395:Histocompatibility Antigens Class I / Q000096:biosynthesis / Q000502:physiology*; D006801:Humans; D007371:Interferon-gamma / Q000494:pharmacology*; D007694:Killer Cells, Natural / Q000187:drug effects / Q000276:immunology*; D007700:Kinetics; D011994:Recombinant Proteins; D012867:Skin / Q000276:immunology; D014162:Transfection; D014471:Umbilical Veins
D002352:Carrier Proteins; D015395:Histocompatibility Antigens Class I; D011994:Recombinant Proteins; D007371:Interferon-gamma