Faculty Opinions recommendation of Assembly and cell surface expression of TAP-independent, chloroquine-sensitive and interferon-gamma-inducible class I MHC complexes in transformed fibroblast cell lines are regulated by tapasin.

2002 ◽  
Author(s):  
Tim Elliott
Keyword(s):  
Cell Surface ◽  
Cell Lines ◽  
Interferon Gamma ◽  
Fibroblast Cell ◽  
Surface Expression ◽  
Class I ◽  
Cell Surface Expression ◽  
Class I Mhc ◽  
Fibroblast Cell Lines

scholarly journals Variations in MHC class I antigen presentation and immunopeptidome selection pathways

F1000Research ◽  
2020 ◽  
Vol 9 ◽  
pp. 1177
Author(s):  
Anita J. Zaitouna ◽  
Amanpreet Kaur ◽  
Malini Raghavan
Keyword(s):  
Cell Surface ◽  
Antigen Presentation ◽  
Surface Expression ◽  
Structural Features ◽  
Class I ◽  
Cell Surface Expression ◽  
Immune Recognition ◽  
Antigen Receptors ◽  
Class I Mhc ◽  
Mhc I

Major histocompatibility class I (MHC-I) proteins mediate immunosurveillance against pathogens and cancers by presenting antigenic or mutated peptides to antigen receptors of CD8+ T cells and by engaging receptors of natural killer (NK) cells. In humans, MHC-I molecules are highly polymorphic. MHC-I variations permit the display of thousands of distinct peptides at the cell surface. Recent mass spectrometric studies have revealed unique and shared characteristics of the peptidomes of individual MHC-I variants. The cell surface expression of MHC-I–peptide complexes requires the functions of many intracellular assembly factors, including the transporter associated with antigen presentation (TAP), tapasin, calreticulin, ERp57, TAP-binding protein related (TAPBPR), endoplasmic reticulum aminopeptidases (ERAPs), and the proteasomes. Recent studies provide important insights into the structural features of these factors that govern MHC-I assembly as well as the mechanisms underlying peptide exchange. Conformational sensing of MHC-I molecules mediates the quality control of intracellular MHC-I assembly and contributes to immune recognition by CD8 at the cell surface. Recent studies also show that several MHC-I variants can follow unconventional assembly routes to the cell surface, conferring selective immune advantages that can be exploited for immunotherapy.

scholarly journals Efficiency of acetylcholine receptor subunit assembly and its regulation by cAMP.

1991 ◽  
Vol 113 (3) ◽  
pp. 623-636 ◽  
Author(s):  
A F Ross ◽  
W N Green ◽  
D S Hartman ◽  
T Claudio
Keyword(s):  
Cell Surface ◽  
Acetylcholine Receptor ◽  
Cell Lines ◽  
Fibroblast Cell ◽  
Surface Expression ◽  
Mouse Fibroblast ◽  
Cell Surface Expression ◽  
Intracellular Camp ◽  
Temperature Sensitive ◽  
Subunit Assembly

Assembly of nicotinic acetylcholine receptor (AChR) subunits was investigated using mouse fibroblast cell lines stably expressing either Torpedo (All-11) or mouse (AM-4) alpha, beta, gamma, and delta AChR subunits. Both cell lines produce fully functional cell surface AChRs. We find that two independent treatments, lower temperature and increased intracellular cAMP can increase AChR expression by increasing the efficiency of subunit assembly. Previously, we showed that the rate of degradation of individual subunits was decreased as the temperature was lowered and that Torpedo AChR expression was acutely temperature sensitive, requiring temperatures lower than 37 degrees C. We find that Torpedo AChR assembly efficiency increases 56-fold as the temperature is decreased from 37 to 20 degrees C. To determine how much of this is a temperature effect on degradation, mouse AChR assembly efficiencies were determined and found to be only approximately fourfold more efficient at 20 than at 37 degrees C. With reduced temperatures, we can achieve assembly efficiencies of Torpedo AChR in fibroblasts of 20-35%. Mouse AChR in muscle cells is also approximately 30% and we obtain approximately 30% assembly efficiency of mouse AChR in fibroblasts (with reduced temperatures, this value approaches 100%). Forskolin, an agent which increases intracellular cAMP levels, increased subunit assembly efficiencies twofold with a corresponding increase in cell surface AChR. Pulse-chase experiments and immunofluorescence microscopy indicate that oligomer assembly occurs in the ER and that AChR oligomers remain in the ER until released to the cell surface. Once released, AChRs move rapidly through the Golgi membrane to the plasma membrane. Forskolin does not alter the intracellular distribution of AChR. Our results indicate that cell surface expression of AChR can be regulated at the level of subunit assembly and suggest a mechanism for the cAMP-induced increase in AChR expression.

scholarly journals Downregulation of peptide transporter genes in cell lines transformed with the highly oncogenic adenovirus 12.

1994 ◽  
Vol 180 (2) ◽  
pp. 477-488 ◽  
Author(s):  
R Rotem-Yehudar ◽  
S Winograd ◽  
S Sela ◽  
J E Coligan ◽  
R Ehrlich
Keyword(s):  
Cell Surface ◽  
Cell Lines ◽  
Surface Expression ◽  
Class I ◽  
Cell Surface Expression ◽  
Peptide Transporter ◽  
Transformed Cells ◽  
Mrna Levels ◽  
Transformed Cell ◽  
I Gene

The expression of class I major histocompatibility complex antigens on the surface of cells transformed by adenovirus 12 (Ad12) is generally very low, and correlates with the high oncogenicity of this virus. In primary embryonal fibroblasts from transgenic mice that express both endogenous H-2 genes and a miniature swine class I gene (PD1), Ad12-mediated transformation results in suppression of cell surface expression of all class I antigens. Although class I mRNA levels of PD1 and H-2Db are similar to those in nonvirally transformed cells, recognition of newly synthesized class I molecules by a panel of monoclonal antibodies is impaired, presumably as a result of inefficient assembly and transport of the class I molecules. Class I expression can be partially induced by culturing cells at 26 degrees C, or by coculture of cells with class I binding peptides at 37 degrees C. Analysis of steady state mRNA levels of the TAP1 and TAP2 transporter genes for Ad12-transformed cell lines revealed that they both are significantly reduced, TAP2 by about 100-fold and TAP1 by 5-10-fold. Reconstitution of PD1 and H-2Db, but not H-2Kb, expression is achieved in an Ad12-transformed cell line by stable transfection with a TAP2, but not a TAP1, expression construct. From these data it may be concluded that suppressed expression of peptide transporter genes, especially TAP2, in Ad12-transformed cells inhibits cell surface expression of class I molecules. The failure to fully reconstitute H-2Db and H-2Kb expression indicates that additional factors are involved in controlling class I gene expression in Ad12-transformed cells. Nevertheless, these results suggest that suppression of peptide transporter genes might be an important mechanism whereby virus-transformed cells escape immune recognition in vivo.

scholarly journals Immunization with SV40-transformed cells yields mainly MHC-restricted monoclonal antibodies.

1986 ◽  
Vol 164 (1) ◽  
pp. 196-210 ◽  
Author(s):  
B G Froscher ◽  
N R Klinman
Keyword(s):  
B Cells ◽  
Cell Surface ◽  
Cell Lines ◽  
Fibroblast Cell ◽  
Surface Antigens ◽  
Transformed Cells ◽  
Cell Surface Antigens ◽  
Class I Mhc ◽  
Sv40 Transformation ◽  
Fibroblast Cell Lines

Recognition of antigens on cell surfaces only in the context of the MHC-encoded alloantigens of the presenting cell (self + X) has classically been considered the province of T cells. However, evidence from several sources has indicated that B cells and antibodies can exhibit self + X-restricted recognition as well. This report concerns the mAb response to SV40-transformed H-2b fibroblast cell lines. The specificities of the antibodies obtained have been analyzed for binding to a panel of SV40-transformed H-2-syngeneic, H-2-allogeneic, and H-2b mutant fibroblast cell lines, as well as cell lines not bearing cell surface SV40 transformation-associated antigens. A large proportion of primary C57BL/6 (71%) and BALB/c (68%) splenic B cells responding to in vitro stimulation with SV40-transformed H-2b cells recognize cell surface antigens associated with SV40 transformation only when coexpressed with MHC antigens of the immunizing cell, particularly the Kb molecule, on transformed cells. To extensively define the nature of antigen recognition by these antibodies, we have generated and characterized nine hybridoma antibodies specific for SV40-transformed H-2-syngeneic cell lines. Seven of these hybridoma antibodies recognize SV40-associated transformation antigens in the context of H-2b molecules. Six of these are restricted by the Kb molecule and discriminate among a panel of SV40-transformed Kb mutant cell lines, thus confirming the participation of class I MHC-encoded molecules in the recognition by B cells of cell surface antigens.

Ku80 autoantigen as a cellular coreceptor for human parvovirus B19 infection

Blood ◽  
2005 ◽  
Vol 106 (10) ◽  
pp. 3449-3456 ◽  
Author(s):  
Yasuhiko Munakata ◽  
Takako Saito-Ito ◽  
Keiko Kumura-Ishii ◽  
Jie Huang ◽  
Takao Kodera ◽  
...  
Keyword(s):  
Bone Marrow ◽  
Cell Surface ◽  
Cell Lines ◽  
Bone Marrow Cells ◽  
Parvovirus B19 ◽  
Surface Expression ◽  
Cell Surface Expression ◽  
Human Parvovirus B19 ◽  
Erythroid Cells ◽  
Interfering Rna

AbstractHuman parvovirus B19 (B19) infects human erythroid cells expressing P antigen. However, some cell lines that were positive for P antigen failed to bind B19, whereas some cell lines had an ability to bind B19 despite undetectable expression of P antigen. We here demonstrate that B19 specifically binds with Ku80 autoantigen on the cell surface. Furthermore, transfection of HeLa cells with the gene of Ku80 enabled the binding of B19 and allowed its entry into cells. Moreover, reduction of cell-surface expression of Ku80 in KU812Ep6 cells, which was a high-sensitive cell line for B19 infection, by short interfering RNA for Ku80 resulted in the marked inhibition of B19 binding in KU812Ep6 cells. Although Ku80 originally has been described as a nuclear protein, human bone marrow erythroid cells with glycophorin A or CD36, B cells with CD20, or T cells with CD3 were all positive for cell-surface expression of Ku80. B19 infection of KU812Ep6 cells and bone marrow cells was inhibited in the presence of anti-Ku80 antibody. Our data suggest that Ku80 functions as a novel coreceptor for B19 infection, and this finding may provide an explanation for the pathologic immunity associated with B19 infection.

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