Major histocompatibility complex class 1 (MHC1) loss among patients with glioblastoma (GBM).

2020 ◽  
Vol 38 (15_suppl) ◽  
pp. e14523-e14523
Author(s):  
Michael Castro ◽  
Bence Sipos ◽  
Natalia Pieper ◽  
Saskia Biskup
Keyword(s):  
Cell Surface ◽  
Antigen Presentation ◽  
Staining Intensity ◽  
Molecular Events ◽  
Intact Membrane ◽  
Mutation Burden ◽  
Frequent Event ◽  
Class 1 ◽  
Immunosuppressive Tumor Microenvironment ◽  
Membrane Bound

e14523 Background: Immune evasion represents a hallmark behavior of cancer and may occur through many mechanisms. Among these, intact tumor antigen presentation at the cell surface is a fundamental prerequisite to achieving successful adaptive immunotherapy. The loss of MHC1 expression due to molecular events, including mutation, deletion, or epigenetic silencing of B2M is commonly acquired during immunotherapy. On the other hand, molecular events affecting antigen presentation machinery may be present prior to immunotherapy administration. Among these, TP53 mutations causing loss of ERAP1 and TAP1 expression compromise transport of MHC1 molecules from the endoplasmic reticulum to the cell surface and mutant peptide integration into the HLA context resulting in absent antigen presentation. Thus far, clinical trials of PD-1/L1 agents have failed to demonstrate a benefit for GBM patients and responses are seen only among a minority. Hence, we set out to assess the integrity of MHC1 expression by using immunohistochemistry. Methods: Immunohistochemical (IHC) stains for HLA, B and C were developed and validated with internal controls. Staining intensity and location (membrane-bound or cytoplasmic) was evaluated semi-quantitatively. The first 10 consecutive patients with GBM who were referred for neoepitope vaccine were evaluated. Results: Absent staining was seen among 6/10, negligible, or faint staining was present in 2, and only 2 tumors demonstrated intact membrane-bound expression. Conclusions: In addition to low tumor mutation burden and an immunosuppressive tumor microenvironment, MHC1 loss is a frequent event among patients with GBM, and may be a dominant cause of immunotherapy failure for as many as 80% of patients. Thus, development of strategies to reverse this loss may be an essential component of successful adaptive immunotherapy for this disease. These data suggest that routine assessment of MHC1 should become a component of eligibility checking for GBM patients being considered for an MHC-restricted approaches. [Table: see text]

Spatial control of actin-based motility through plasmalemmal PtdIns(4,5)P2-rich raft assemblies.

2005 ◽  
Vol 72 ◽  
pp. 119-127 ◽  
Author(s):  
Tamara Golub ◽  
Caroni Pico
Keyword(s):  
Protein Kinase ◽  
Cell Surface ◽  
Actin Cytoskeleton ◽  
Lipid Rafts ◽  
Patch Clustering ◽  
Pkc Protein Kinase C ◽  
Membrane Bound ◽  
And Function ◽  
Cytoskeleton Dynamics ◽  
Syndrome Protein

The interactions of cells with their environment involve regulated actin-based motility at defined positions along the cell surface. Sphingolipid- and cholesterol-dependent microdomains (rafts) order proteins at biological membranes, and have been implicated in most signalling processes at the cell surface. Many membrane-bound components that regulate actin cytoskeleton dynamics and cell-surface motility associate with PtdIns(4,5)P2-rich lipid rafts. Although raft integrity is not required for substrate-directed cell spreading, or to initiate signalling for motility, it is a prerequisite for sustained and organized motility. Plasmalemmal rafts redistribute rapidly in response to signals, triggering motility. This process involves the removal of rafts from sites that are not interacting with the substrate, apparently through endocytosis, and a local accumulation at sites of integrin-mediated substrate interactions. PtdIns(4,5)P2-rich lipid rafts can assemble into patches in a process depending on PtdIns(4,5)P2, Cdc42 (cell-division control 42), N-WASP (neural Wiskott-Aldrich syndrome protein) and actin cytoskeleton dynamics. The raft patches are sites of signal-induced actin assembly, and their accumulation locally promotes sustained motility. The patches capture microtubules, which promote patch clustering through PKA (protein kinase A), to steer motility. Raft accumulation at the cell surface, and its coupling to motility are influenced greatly by the expression of intrinsic raft-associated components that associate with the cytosolic leaflet of lipid rafts. Among them, GAP43 (growth-associated protein 43)-like proteins interact with PtdIns(4,5)P2 in a Ca2+/calmodulin and PKC (protein kinase C)-regulated manner, and function as intrinsic determinants of motility and anatomical plasticity. Plasmalemmal PtdIns(4,5)P2-rich raft assemblies thus provide powerful organizational principles for tight spatial and temporal control of signalling in motility.

scholarly journals Artificial intelligence predicts the immunogenic landscape of SARS-CoV-2 leading to universal blueprints for vaccine designs

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Brandon Malone ◽  
Boris Simovski ◽  
Clément Moliné ◽  
Jun Cheng ◽  
Marius Gheorghe ◽  
...  
Keyword(s):  
Artificial Intelligence ◽  
Monte Carlo ◽  
Cell Surface ◽  
Antigen Presentation ◽  
Human Population ◽  
Host Immune System ◽  
T Cell Epitopes ◽  
Digital Twin ◽  
Novel Coronavirus ◽  
Global Population

AbstractThe global population is at present suffering from a pandemic of Coronavirus disease 2019 (COVID-19), caused by the novel coronavirus Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2). The goal of this study was to use artificial intelligence (AI) to predict blueprints for designing universal vaccines against SARS-CoV-2, that contain a sufficiently broad repertoire of T-cell epitopes capable of providing coverage and protection across the global population. To help achieve these aims, we profiled the entire SARS-CoV-2 proteome across the most frequent 100 HLA-A, HLA-B and HLA-DR alleles in the human population, using host-infected cell surface antigen presentation and immunogenicity predictors from the NEC Immune Profiler suite of tools, and generated comprehensive epitope maps. We then used these epitope maps as input for a Monte Carlo simulation designed to identify statistically significant “epitope hotspot” regions in the virus that are most likely to be immunogenic across a broad spectrum of HLA types. We then removed epitope hotspots that shared significant homology with proteins in the human proteome to reduce the chance of inducing off-target autoimmune responses. We also analyzed the antigen presentation and immunogenic landscape of all the nonsynonymous mutations across 3,400 different sequences of the virus, to identify a trend whereby SARS-COV-2 mutations are predicted to have reduced potential to be presented by host-infected cells, and consequently detected by the host immune system. A sequence conservation analysis then removed epitope hotspots that occurred in less-conserved regions of the viral proteome. Finally, we used a database of the HLA haplotypes of approximately 22,000 individuals to develop a “digital twin” type simulation to model how effective different combinations of hotspots would work in a diverse human population; the approach identified an optimal constellation of epitope hotspots that could provide maximum coverage in the global population. By combining the antigen presentation to the infected-host cell surface and immunogenicity predictions of the NEC Immune Profiler with a robust Monte Carlo and digital twin simulation, we have profiled the entire SARS-CoV-2 proteome and identified a subset of epitope hotspots that could be harnessed in a vaccine formulation to provide a broad coverage across the global population.

SHEDDING OF SURFACE PROTEINS BY PORCINE THYROID CELLS

1980 ◽  
Vol 85 (2) ◽  
pp. 245-251 ◽  
Author(s):  
A. BRENNAN ◽  
P. M. POVEY ◽  
B. REES SMITH ◽  
R. HALL
Keyword(s):  
Cell Surface ◽  
Sodium Dodecyl Sulphate ◽  
Culture Medium ◽  
Cell Metabolism ◽  
Sodium Dodecyl ◽  
Surface Proteins ◽  
Half Time ◽  
Thyroid Cells ◽  
Peptide Cleavage ◽  
Membrane Bound

Isolated porcine thyroid cells were surface-labelled with 125I using the lactoperoxidase technique. Samples of the cells were then cultured and harvested at various intervals for up to 7 days. The labelled proteins remaining on the cells or shed into the culture medium were analysed by electrophoresis on polyacrylamide gels run in sodium dodecyl sulphate. These studies indicated that the several different surface proteins of the thyroid cells were lost from the cell surface at similar rates (half-time of approximately 28 h) as the result, at least in part, of a process which depended on active cell metabolism. In addition, the gel profiles obtained from analysis of both medium and membrane-bound labelled proteins were similar and this suggested that peptide cleavage was not involved in the shedding of the majority of these proteins.

scholarly journals The antigen presentation function of bone marrow-derived mast cells is spatiotemporally restricted to a subset expressing high levels of cell surface FcεRI and MHC II

2010 ◽  
Vol 11 (1) ◽  
pp. 34 ◽  
Author(s):  
Jian Gong ◽  
Ning-Sun Yang ◽  
Michael Croft ◽  
I-Chun Weng ◽  
Liangwu Sun ◽  
...  
Keyword(s):  
Bone Marrow ◽  
Mast Cells ◽  
Cell Surface ◽  
Antigen Presentation ◽  
Mhc Ii

scholarly journals Drebrin 1 in dendritic cells regulates phagocytosis and cell surface receptor expression through recycling for efficient antigen presentation

Immunology ◽  
2018 ◽  
Vol 156 (2) ◽  
pp. 136-146 ◽  
Author(s):  
Diana M. Elizondo ◽  
Temesgen E. Andargie ◽  
Naomi L. Haddock ◽  
Thomas A. Boddie ◽  
Michael W. Lipscomb
Keyword(s):  
Dendritic Cells ◽  
Cell Surface ◽  
Antigen Presentation ◽  
Receptor Expression ◽  
Cell Surface Receptor ◽  
Surface Receptor

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 Rapid purification of glycosyl-phosphatidylinositol-anchored alkaline phosphatase from human neutrophils after up-regulation to the cell surface.

1993 ◽  
Vol 41 (9) ◽  
pp. 1367-1372 ◽  
Author(s):  
T J Cain ◽  
Y Liu ◽  
T Kobayashi ◽  
J M Robinson
Keyword(s):  
Alkaline Phosphatase ◽  
Cell Surface ◽  
Human Neutrophils ◽  
Extracellular Medium ◽  
Isolation And Purification ◽  
Glycosyl Phosphatidylinositol ◽  
Associated Proteins ◽  
Membrane Bound ◽  
Pre Treatment ◽  
Rapid Purification

Alkaline phosphatase (APase) belongs to a growing family of membrane-associated proteins tethered to the lipid bilayer via a glycosyl-phosphatidylinositol (GPI) anchor. Human neutrophils contain an intracellular pool of APase associated with a novel membrane-bound compartment. Stimulation of neutrophils with the chemotactic peptide formyl-Met-Leu-Phe (fMLP) leads to rapid up-regulation of essentially all of the APase to sites in continuity with the extracellular medium. Pre-treatment of neutrophils with cytochalasin B (cyto B) followed by fMLP likewise leads to expression of the enzyme on the cell surface and a dramatic alteration in cell morphology, but subsequent internalization of the plasmalemma is minimized. Pre-treatment with cyto B and fMLP has been used for isolation and purification of neutrophil APase. Specifically, neutrophils were treated with phosphatidylinositol-specific phospholipase C to release GPI-anchored proteins from the cell surface. APase was purified from supernatants of these preparations by electrophoresis in a non-denaturing gel system and subsequent electroelution. With this approach we rapidly purified neutrophil APase to homogeneity; this protein was then used for immunization. Immunoblotting, ELISA, and immunocytochemical localization were used to characterize the resulting antibodies.

scholarly journals A Disintegrin and Metalloproteases (ADAMs) in Cardiovascular, Metabolic and Inflammatory Diseases: Aspects for Theranostic Approaches

2018 ◽  
Vol 118 (07) ◽  
pp. 1167-1175 ◽  
Author(s):  
Emiel van der Vorst ◽  
Christian Weber ◽  
Marjo Donners
Keyword(s):  
Rheumatoid Arthritis ◽  
Growth Factors ◽  
Membrane Proteins ◽  
Cell Surface ◽  
Inflammatory Diseases ◽  
Cell Surface Molecules ◽  
Surface Molecules ◽  
Membrane Bound ◽  
Membrane Bound Enzymes ◽  
Key Questions

AbstractA disintegrin and metalloproteases (ADAMs) are membrane-bound enzymes responsible for the shedding or cleavage of various cell surface molecules, such as adhesion molecules, cytokines/chemokines and growth factors. This shedding can result in the release of soluble proteins that can exert agonistic or antagonistic functions. Additionally, ADAM-mediated cleavage can render these membrane proteins inactive. This review will describe the role and association of ADAMs in various pathologies with a main focus on ADAM10 and ADAM17 in atherosclerosis, including a brief overview of atherosclerosis-related ADAM substrates. Furthermore, ADAMs involvement in other metabolic and inflammatory diseases like diabetes, sepsis, Alzheimer's disease and rheumatoid arthritis will be highlighted. Subsequently, we will briefly discuss an interesting emerging field of research, i.e. the potential implications of ADAM expression in extracellular vesicles. Finally, several ADAM-based therapeutic and diagnostic (theranostic) opportunities will be discussed, while focusing on key questions about the required specificity and selectivity.

PAF-induced elastase-dependent neutrophil transendothelial migration is associated with the mobilization of elastase to the neutrophil surface and localization to the migrating front

1999 ◽  
Vol 112 (12) ◽  
pp. 1937-1945 ◽  
Author(s):  
G. Cepinskas ◽  
M. Sandig ◽  
P.R. Kvietys
Keyword(s):  
Cell Surface ◽  
Acute Inflammation ◽  
Umbilical Vein ◽  
Platelet Activating Factor ◽  
Transendothelial Migration ◽  
Extracellular Milieu ◽  
Affected Tissue ◽  
Membrane Bound ◽  
Neutrophil Surface ◽  
Chemotactic Gradient

One of the cardinal signs of acute inflammation is neutrophil (PMN) emigration across the endothelium and into the affected tissue. We have previously shown that human PMN migration across human umbilical vein endothelial cell (HUVEC) monolayers is dependent on PMN-derived elastase. However, whether migrating PMN release elastase into the extracellular milieu or retain it on the cell surface is unclear. In the present study, we show that when PMN are activated by platelet activating factor (PAF), elastase was mobilized to and retained in the cell membrane; no elastase activity was detected in the supernatant. Neutroplasts (enucleated cells devoid of granules) prepared from PAF-activated PMN contained twice as much elastase as did neutroplasts prepared from unstimulated PMN. Neutroplasts from PAF-activated PMN migrated across HUVEC monolayers in response to a chemotactic gradient (PAF), while those prepared from unstimulated PMN did not. The neutroplast transendothelial migration was inhibited (80%) by a monoclonal antibody against elastase. Using confocal microscopy, we noted that the localization of elastase on the cell surface of PMN, which were adherent to HUVEC but not migrating, was largely confined to the apical aspect of the PMN. There was little or no elastase detectable on the basal aspect of the PMN membrane in contact with the endothelium. By contrast, in migrating PMN the membrane-bound elastase was primarily localized to the migrating front, i.e. pseudopodia penetrating the HUVEC monolayers. Taken together, our findings indicate that migrating PMN localize their membrane-bound elastase to the migrating front where it facilitates transendothelial migration.

scholarly journals Role of glycosylation in transport and enzymic activity of neutral endopeptidase-24.11

1994 ◽  
Vol 302 (2) ◽  
pp. 451-454 ◽  
Author(s):  
M H Lafrance ◽  
C Vézina ◽  
Q Wang ◽  
G Boileau ◽  
P Crine ◽  
...  
Keyword(s):  
Enzyme Activity ◽  
Cell Surface ◽  
Intracellular Transport ◽  
Neutral Endopeptidase ◽  
Soluble Form ◽  
Cell Extracts ◽  
Glycosylation Sites ◽  
Sugar Addition ◽  
Membrane Bound

Neutral endopeptidase (NEP, EC 3.4.24.11) is a major ectoenzyme of the brush-border membrane. The ectodomain of NEP contains five putative N-glycosylation sites. In order to determine the role of the addition of sugar moieties on the activity and intracellular transport of NEP, we have used site-directed mutagenesis to remove all or some of the five potential sites of sugar addition in membrane-bound and secreted forms of the enzyme. Expression of NEP glycosylation mutants in COS-1 cells showed that all five sites are used for sugar addition. Immunoblotting of NEP in COS-1 cell extracts or culture media indicated that total expression of normal membrane-bound NEP was not affected by mutations at glycosylation sites, whereas this expression level appeared to be strictly dependent on the number of glycosylation sites retained on the soluble form. The transport to the cell surface was also reduced by decreased glycosylation, but again the phenomenon appeared more drastic in the case of the soluble form than for the membrane-bound enzyme. Enzyme activity was decreased by deglycosylation. However, the presence of either of two crucial sites (sites 1 and 5; numbered from the N-terminus of the protein) was sufficient to recover close-to-normal enzymic activities. Transport to the cell surface and enzyme activity of NEP are thus both dependent on sugar residues, probably through different conformational constraints. These constraints seem to be local for enzyme activity but more global for transport to the cell surface.

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