scholarly journals Transcriptional regulation of MHC class I gene expression in rat oligodendrocytes

1998 ◽  
Vol 330 (1) ◽  
pp. 155-161 ◽  
Author(s):  
Georgia MAVRIA ◽  
T. Kersten HALL ◽  
A. Richard JONES ◽  
G. Eric BLAIR
Keyword(s):  
Mhc Class I ◽  
Promoter Activity ◽  
Regulatory Element ◽  
Regulatory Elements ◽  
Class I ◽  
Cell Leukaemia ◽  
Type I ◽  
Down Regulation ◽  
Leukaemia Virus ◽  
Negative Regulatory Element

MHC class I molecules are normally expressed at very low levels in the brain and their up-regulation in response to cytokines and viral infections has been associated with a number of neurological disorders. Here we demonstrate that the down-regulation of surface class I molecules in differentiated primary rat oligodendrocytes was accompanied by reduced steady-state levels of class I heavy-chain mRNA. Transient expression assays were performed in oligodendrocytes and fibroblasts, using a mouse H-2Kb class I promoter chloramphenicol acetyltransferase plasmid termed pH2KCAT (which contained 5ʹ-flanking sequences from -2033 to +5 bp of the H-2Kb gene relative to the transcriptional start site at +1 bp). These assays showed that H-2Kb promoter activity was reduced in oligodendrocytes but not in class I-expressing fibroblasts. H-2Kb promoter activity was up-regulated in oligodendrocytes co-transfected with a plasmid expression vector encoding the transcriptional activator tax of human T-cell leukaemia virus type I, showing that down-regulation of promoter activity was reversible. Deletion mutant analysis of the H-2Kb promoter revealed the presence of negative regulatory elements that were functional in oligodendrocytes at -1.61 to -1.07 kb and -242 to -190 bp. Deletion of sequences in pH2KCAT encompassing the downstream element totally abolished promoter activity in both oligodendrocytes and fibroblasts, whereas a deletion within the upstream negative regulatory element increased promoter activity specifically in oligodendrocytes. The upstream negative regulatory element also down-regulated a linked heterologous herpes simplex virus thymidine kinase promoter in oligodendrocytes, but not in fibroblasts. Gel retardation assays using overlapping DNA probes that spanned the entire -1.61 to -1.07 kb region revealed the presence of a number of DNA-binding activities that were present in oligodendrocyte, but not in fibroblast nuclear extracts.

scholarly journals Repression of MHC class I gene promoter activity by two-exon Tat of HIV

Science ◽  
1993 ◽  
Vol 260 (5112) ◽  
pp. 1320-1322 ◽  
Author(s):  
T. Howcroft ◽  
K Strebel ◽  
M. Martin ◽  
D. Singer
Keyword(s):  
Mhc Class I ◽  
Promoter Activity ◽  
Gene Promoter ◽  
Class I ◽  
I Gene ◽  
Mhc Class I Gene

The role of DNA methylation in the down-regulation of MHC class I in a series of murine lymphoma variants

1994 ◽  
Vol 40 ◽  
pp. 60
Author(s):  
R. Rubocki ◽  
B. Berrigan ◽  
S. Shepherd ◽  
J. Wisecarver
Keyword(s):  
Dna Methylation ◽  
Mhc Class I ◽  
Class I ◽  
Down Regulation ◽  
Murine Lymphoma

T-cell epitopes within the complementarity-determining and framework regions of the tumor-derived immunoglobulin heavy chain in multiple myeloma

Blood ◽  
2003 ◽  
Vol 101 (12) ◽  
pp. 4930-4936 ◽  
Author(s):  
Lotta Hansson ◽  
Hodjattallah Rabbani ◽  
Jan Fagerberg ◽  
Anders Österborg ◽  
Håkan Mellstedt
Keyword(s):  
Multiple Myeloma ◽  
T Cells ◽  
T Cell ◽  
Mhc Class I ◽  
Heavy Chain ◽  
T Cell Response ◽  
Class I ◽  
Type I ◽  
T Cell Epitopes ◽  
Hla Binding

Abstract The idiotypic structure of the monoclonal immunoglobulin (Ig) in multiple myeloma (MM) might be regarded as a tumor-specific antigen. The present study was designed to identify T-cell epitopes of the variable region of the Ig heavy chain (VH) in MM (n = 5) using bioinformatics and analyze the presence of naturally occurring T cells against idiotype-derived peptides. A large number of human-leukocyte-antigen (HLA)–binding (class I and II) peptides were identified. The frequency of predicted epitopes depended on the database used: 245 in bioinformatics and molecular analysis section (BIMAS) and 601 in SYFPEITHI. Most of the peptides displayed a binding half-life or score in the low or intermediate affinity range. The majority of the predicted peptides were complementarity-determining region (CDR)–rather than framework region (FR)–derived (52%-60% vs 40%-48%, respectively). Most of the predicted peptides were confined to the CDR2-FR3-CDR3 “geographic” region of the Ig-VH region (70%), and significantly fewer peptides were found within the flanking (FR1-CDR1-FR2 and FR4) regions (P < .01). There were 8– to 10–amino acid (aa) long peptides corresponding to the CDRs and fitting to the actual HLA-A/B haplotypes that spontaneously recognized, albeit with a low magnitude, type I T cells (interferon γ), indicating an ongoing major histocompatibility complex (MHC) class I–restricted T-cell response. Most of those peptides had a low binding half-life (BIMAS) and a low/intermediate score (SYFPEITHI). Furthermore, 15- to 20-aa long CDR1-3–derived peptides also spontaneously recognized type I T cells, indicating the presence of MHC class II–restricted T cells as well. This study demonstrates that a large number of HLA-binding idiotypic peptides can be identified in patients with MM. Such peptides may spontaneously induce a type I MHC class I– as well as class II–restricted memory T-cell response.

scholarly journals No real homology of human T-cell leukaemia virus envelope with class I HLA

Nature ◽  
1984 ◽  
Vol 308 (5954) ◽  
pp. 85-85 ◽  
Author(s):  
M. F. CLARKE ◽  
E. P. GELMANN ◽  
M. S. REITZ
Keyword(s):  
T Cell ◽  
Class I ◽  
Cell Leukaemia ◽  
Virus Envelope ◽  
Leukaemia Virus ◽  
Human T Cell

Central Role of the Antigen-Presentation and Interferon-γ Pathways in Resistance to Immune Checkpoint Blockade

2021 ◽  
Vol 6 (1) ◽  
Author(s):  
Annette Paschen ◽  
Ignacio Melero ◽  
Antoni Ribas
Keyword(s):  
Antigen Presentation ◽  
Tumor Cells ◽  
Mhc Class I ◽  
Cancer Biology ◽  
Interleukin 2 ◽  
Interferon Γ ◽  
Class I ◽  
Annual Review ◽  
Publication Date ◽  
Type I

Resistance to immunotherapy is due in some instances to the acquired stealth mechanisms of tumor cells that lose expression of MHC class I antigen–presenting molecules or downregulate their class I antigen–presentation pathways. Most dramatically, biallelic β2-microglobulin (B2M) loss leads to complete loss of MHC class I expression and to invisibility to CD8+ T cells. MHC class I expression and antigen presentation are potently upregulated by interferon-γ (IFNγ) in a manner that depends on IFNγ receptor (IFNGR) signaling via JAK1 and JAK2. Mutations in these molecules lead to IFNγ unresponsiveness and mediate loss of recognition and killing by cytotoxic T lymphocytes. Loss of MHC class I augments sensitivity of tumor cells to be killed by natural killer (NK) lymphocytes, and this mechanism could be exploited to revert resistance, for instance, with interleukin-2 (IL-2)-based agents. Moreover, in some experimental models, potent local type I interferon responses, such as those following intratumoral injection of Toll-like receptor 9 (TLR9) or TLR3 agonists, revert resistance due to mutations of JAKs. Expected final online publication date for the Annual Review of Cancer Biology, Volume 6 is April 2022. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.

scholarly journals Th-1 polarization is regulated by dendritic-cell comparison of MHC class I and class II antigens

Blood ◽  
2009 ◽  
Vol 113 (18) ◽  
pp. 4213-4223 ◽  
Author(s):  
William K. Decker ◽  
Dongxia Xing ◽  
Sufang Li ◽  
Simon N. Robinson ◽  
Hong Yang ◽  
...  
Keyword(s):  
Mhc Class I ◽  
Class Ii ◽  
Class I ◽  
Antigenic Specificity ◽  
Type I ◽  
Peptide Epitopes ◽  
Transcriptional Signature ◽  
Surface Marker Expression ◽  
Conceptual Explanations ◽  
Th 1

Abstract In the control of T-helper type I (Th-1) polarization, dendritic cells (DCs) must interpret a complex array of stimuli, many of which are poorly understood. Here we demonstrate that Th-1 polarization is heavily influenced by DC-autonomous phenomena triggered by the loading of DCs with antigenically matched major histocompatibility complex (MHC) class I and class II determinants, that is, class I and II peptide epitopes exhibiting significant amino acid sequence overlap (such as would be physiologically present during infectious processes requiring Th-1 immunity for clearance). Data were derived from 13 independent antigenic models including whole-cell systems, single-protein systems, and 3 different pairs of overlapping class I and II binding epitopes. Once loaded with matched class I and II antigens, these “Th-1 DCs” exhibited differential cytokine secretion and surface marker expression, a distinct transcriptional signature, and acquired the ability to enhance generation of CD8+ T lymphocytes. Mechanistically, tRNA-synthetases were implicated as components of a putative sensor complex involved in the comparison of class I and II epitopes. These data provide rigorous conceptual explanations for the process of Th-1 polarization and the antigenic specificity of cognate T-cell help, enhance the understanding of Th-1 responses, and should contribute to the formulation of more effective vaccination strategies.

Protective effect of interferon ? on human T cell leukaemia virus type I infection of CD4+ T cells isolated from human cord blood

1993 ◽  
Vol 37 (2) ◽  
pp. 97-104 ◽  
Author(s):  
Beatrice Macchi ◽  
Isabella Faraoni ◽  
Antonio Mastino ◽  
Chiara D'Onofrio ◽  
Gianna Romeo ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
Protective Effect ◽  
Cord Blood ◽  
Virus Type ◽  
Cell Leukaemia ◽  
Type I ◽  
Human Cord Blood ◽  
Leukaemia Virus ◽  
Human T Cell
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