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Jeong Hoo Lee, Jahyang Choi, Yong-Oon Ahn, Tae Min Kim, Dae Seog Heo
Extranodal natural killer (NK)/T-cell lymphoma is an aggressive malignant disease that is associated with Epstein-Barr viral (EBV) infection. To date, the mechanism of viral entry into NK cells remains uncertain. Here, we investigated this mechanism using human NK cells in vitro. CD21 mRNA expression, an EBV-entry receptor, was transiently detected in NK cells after exosome treatment, and levels decreased after further culture. CD21 protein expression was also transiently transferred to NK cells after co-culture with an EBV-positive Burkitt lymphoma cell line (Raji) via trogocytosis...
January 17, 2018: Cellular Immunology
Makoto Nakashima, Mariko Watanabe, Kaoru Uchimaru, Ryouichi Horie
BACKGROUND INFORMATION: CD30, which is characteristically expressed in classical Hodgkin lymphoma (cHL), is thought to transduce signals by ligation of trimerized CD30 ligand (CD30L) on the surface of surrounding cells and recruitment of downstream molecules. In this report, we propose a new mechanism for CD30 signaling by its ligand. We prepared two stable transformants, CHO cells expressing CD30L fused to mCherry and HeLa cells expressing CD30 fused to GFP. RESULTS: Co-culture of these cells triggered clustering of CD30 and CD30L at the cellular interface, formation of multiple CD30L-CD30 complexes, internalization of these complexes with a portion of the plasma membrane into the HeLa cells, and intracellular transport to the lysosomal compartment...
February 12, 2018: Biology of the Cell
Frances Mercer, Shek Hang Ng, Taylor M Brown, Grace Boatman, Patricia J Johnson
T. vaginalis, a human-infective parasite, causes the most common nonviral sexually transmitted infection (STI) worldwide and contributes to adverse inflammatory disorders. The immune response to T. vaginalis is poorly understood. Neutrophils (polymorphonuclear cells [PMNs]) are the major immune cell present at the T. vaginalis-host interface and are thought to clear T. vaginalis. However, the mechanism of PMN clearance of T. vaginalis has not been characterized. We demonstrate that human PMNs rapidly kill T...
February 6, 2018: PLoS Biology
Yoelys Cruz-Leal, Danielle Marjoram, Alan H Lazarus
Anti-D prevents hemolytic disease of the fetus and newborn, and this mechanism has been referred to as Ab-mediated immune suppression (AMIS). Anti-D, as well as other polyclonal AMIS-inducing Abs, most often induce both epitope masking and erythrocyte clearance mechanisms. We have previously observed that some Abs that successfully induce AMIS effects could be split into those that mediate epitope masking versus those that induce erythrocyte clearance, allowing the ability to analyze these mechanisms separately...
January 22, 2018: Journal of Immunology: Official Journal of the American Association of Immunologists
Allissia A Gilmartin, William A Petri
No abstract text is available yet for this article.
December 6, 2017: Microbial Cell
Johannes S Gach, Margaux Bouzin, Marcus P Wong, Veronika Chromikova, Andrea Gorlani, Kuan-Ting Yu, Brijesh Sharma, Enrico Gratton, Donald N Forthal
Fc gamma receptor (FcyR)-mediated antibody functions play a crucial role in preventing HIV infection. One such function, antibody-dependent phagocytosis (ADP), is thought to be involved in controlling other viral infections, but its role in HIV infection is unknown. We measured the ability of HIV-specific polyclonal and monoclonal antibodies (mAbs) to mediate the internalization of HIV-1 virions and HIV-1-decorated cells by phagocytes. To measure ADP of virions, we primarily used a green-fluorescent protein-expressing molecular clone of HIV-1JRFL, an R5, clinical isolate, in combination with polyclonal HIVIG or mAbs known to capture and/or neutralize HIV-1...
December 27, 2017: PLoS Pathogens
Else Marit Inderberg, Nadia Mensali, Morten P Oksvold, Lars-Egil Fallang, Anne Fåne, Gjertrud Skorstad, Grethe-Elisabeth Stenvik, Cinzia Progida, Oddmund Bakke, Gunnar Kvalheim, June H Myklebust, Sébastien Wälchli
Adoptive cell therapy with T-cell receptor (TCR)-engineered T cells represents a powerful method to redirect the immune system against tumours. However, although TCR recognition is restricted to a specific peptide-MHC (pMHC) complex, increasing numbers of reports have shown cross-reactivity and off-target effects with severe consequences for the patients. This demands further development of strategies to validate TCR safety prior to clinical use. We reasoned that the desired TCR signalling depends on correct pMHC recognition on the outside and a restricted clustering on the inside of the cell...
December 16, 2017: Cancer Immunology, Immunotherapy: CII
Jakub Krejcik, Kris A Frerichs, Inger S Nijhof, Berris van Kessel, Jeroen F van Velzen, Andries C Bloem, Marloes E C Broekmans, Sonja Zweegman, Johan van Meerloo, René J P Musters, Pino J Poddighe, Richard W J Groen, Christopher Chiu, Torben Plesner, Henk M Lokhorst, A Kate Sasser, Tuna Mutis, Niels W C J van de Donk
Purpose: Daratumumab treatment results in a marked reduction of CD38 expression on multiple myeloma cells. The aim of this study was to investigate the clinical implications and the underlying mechanisms of daratumumab-mediated CD38 reduction. Experimental Design: We evaluated the effect of daratumumab alone or in combination with lenalidomide-dexamethasone, on CD38 levels of multiple myeloma cells and nontumor immune cells in the GEN501 study (daratumumab monotherapy) and the GEN503 study (daratumumab combined with lenalidomide-dexamethasone)...
December 15, 2017: Clinical Cancer Research: An Official Journal of the American Association for Cancer Research
Allissia A Gilmartin, Katherine S Ralston, William A Petri
Entamoeba histolytica ingests fragments of live host cells in a nibbling-like process termed amebic trogocytosis. Amebic trogocytosis is required for cell killing and contributes to tissue invasion, which is a hallmark of invasive amebic colitis. Work done prior to the discovery of amebic trogocytosis showed that acid vesicles are required for amebic cytotoxicity. In the present study, we show that acidified lysosomes are required for amebic trogocytosis and cell killing. Interference with lysosome acidification using ammonium chloride, a weak base, or concanamycin A, a vacuolar H(+) ATPase inhibitor, decreased amebic trogocytosis and amebic cytotoxicity...
August 29, 2017: MBio
Samuel W French
The immunologic synapse mechanism of liver necrosis was termed Troxis Necrosis meaning "nibbling". (Wang MX et al. and French SW. Exp Mol Pathol 2001, 71: 137-146). This mechanism of liver injury was first named "Piecemeal Necrosis" by Hans Popper. It is involved in autoimmune hepatitis, HCV, HBV, primary biliary cirrhosis and steatohepatitis. This process involves the T cell receptor (TCR) which binds to the hepatocyte antigen presenting major histocompatibility complex (MHC) on the hepatocytic plasma membrane which quickly leads to the removal of the complex from the liver and uptake by the CD4 lymphocyte...
October 2017: Experimental and Molecular Pathology
Somlata, Kumiko Nakada-Tsukui, Tomoyoshi Nozaki
The protozoan parasite Entamoeba histolytica is the aetiologic agent of amoebiasis, an endemic infection in developing countries with considerable morbidity and mortality. Recently, trogocytosis has been recognized as the key step in amoebic cytolysis and invasion, a paradigm shift in understanding pathogenicity of this organism. Here we report that AGC family kinase 1 is specifically involved in trogocytosis of live human cells and does not participate in phagocytosis of dead cells. Live imaging reveals localization of this kinase in the long and thin tunnels formed during trogocytosis but not in the trogosomes (endosomes formed after trogocytosis)...
July 17, 2017: Nature Communications
Sladjana Skopelja-Gardner, Jonathan D Jones, B JoNell Hamilton, Alexey V Danilov, William F C Rigby
Rituximab (RTX) has been the hallmark anti-CD20 mAb for the treatment of B cell neoplasms, including B cell chronic lymphocytic leukemia (B-CLL). Recently, a novel humanized anti-CD20 mAb obinutuzumab (GA101) has been implemented as first-line CLL therapy. Treatment of CLL patients with RTX is associated with CD20 loss via an FcγR-mediated process, trogocytosis. RTX-induced trogocytosis has been characterized as both the means of resistance to therapy, via loss of cell surface target proteins (antigenic modulation), as well as a process that alters B cell phenotype and function...
August 15, 2017: Journal of Immunology: Official Journal of the American Association of Immunologists
Aleksandr Barinov, Alessia Galgano, Gerald Krenn, Corinne Tanchot, Florence Vasseur, Benedita Rocha
CD4+ T cell help to CD8+ T cell responses requires that CD4+ and CD8+ T cells interact with the same antigen presenting dendritic cell (Ag+DC), but it remains controversial whether helper signals are delivered indirectly through a licensed DC and/or involve direct CD4+/CD8+ T cell contacts and/or the formation of ternary complexes. We here describe the first in vivo imaging of the intact spleen, aiming to evaluate the first interactions between antigen-specific CD4+, CD8+ T cells and Ag+DCs. We show that in contrast to CD4+ T cells which form transient contacts with Ag+DC, CD8+ T cells form immediate stable contacts and activate the Ag+DC, acquire fragments of the DC membranes by trogocytosis, leading to their acquisition of some of the DC properties...
2017: PloS One
Yoshinori Yamanishi, Kensuke Miyake, Misako Iki, Hidemitsu Tsutsui, Hajime Karasuyama
Basophils, the least common granulocytes, represent only ~0.5% of peripheral blood leukocytes. Because of the small number and some similarity with mast cells, the functional significance of basophils remained questionable for a long time. Recent studies using newly-developed analytical tools have revealed crucial and non-redundant roles for basophils in various immune responses, particularly Th2 immunity including allergy and protective immunity against parasitic infections. In this review, we discuss the mechanisms how basophils mediate Th2 immune responses and the nature of basophil-derived factors involved in them...
July 2017: Immunological Reviews
Christopher Utter, Adelfa E Serrano, John W Glod, Michael J Leibowitz
Endothelial abnormalities play a critical role in the pathogenesis of malaria caused by the human pathogen, Plasmodium falciparum. In serious infections and especially in cerebral malaria, red blood cells infected with the parasite are sequestered in small venules in various organs, resulting in endothelial activation and vascular occlusion, which are believed to be largely responsible for the morbidity and mortality caused by this infection, especially in children. We demonstrate that after incubation with infected red blood cells (iRBCs), cultured human umbilical vein endothelial cells (HUVECs) contain parasite protein, genomic DNA, and RNA, as well as intracellular vacuoles with apparent parasite-derived material, but not engulfed or adherent iRBCs...
June 2017: Yale Journal of Biology and Medicine
Ayse Basak Engin
Obesity is characterized by the chronic low-grade activation of the innate immune system. In this respect, macrophage-elicited metabolic inflammation and adipocyte-macrophage interaction has a primary importance in obesity. Large amounts of macrophages are accumulated by different mechanisms in obese adipose tissue. Hypertrophic adipocyte-derived chemotactic monocyte chemoattractant protein-1 (MCP-1)/C-C chemokine receptor 2 (CCR2) pathway also promotes more macrophage accumulation into the obese adipose tissue...
2017: Advances in Experimental Medicine and Biology
Rut Valgardsdottir, Irene Cattaneo, Christian Klein, Martino Introna, Marina Figliuzzi, Josée Golay
Polymorphonuclear neutrophils (PMNs) have previously been reported to mediate phagocytosis of anti-CD20-opsonized B cells from patients with chronic lymphocytic leukemia (CLL). However, recent data have suggested that PMNs, like macrophages, can also mediate trogocytosis. We have performed experiments to more precisely investigate this point and to discriminate between trogocytosis and phagocytosis. In live-cell time-lapse microscopy experiments, we could not detect any significant phagocytosis by purified PMNs of anti-CD20-opsonized CLL B cells, but could detect only the repeated close contact between effectors and targets, which suggested trogocytosis...
May 11, 2017: Blood
Carla R Nowosad, Pavel Tolar
Surrogate planar and membrane systems have been employed to study the architecture of immune synapses; however, they often do not recapitulate trans-synaptic extraction and endocytosis of ligands by the immune cells. Transendocytosis (or trogocytosis) of antigen from immune synapses is particularly critical for antigen processing and presentation by B cells. Here we describe a protocol for preparation of plasma membrane sheets (PMSs), which are flexible and fluid membrane substrates that support robust B cell antigen extraction...
2017: Methods in Molecular Biology
Lavanya Thiruchelvam-Kyle, Sigurd E Hoelsbrekken, Per C Saether, Elisabeth Gyllensten Bjørnsen, Daniela Pende, Sigbjørn Fossum, Michael R Daws, Erik Dissen
The functions of activating members of the killer cell Ig-like receptor (KIR) family are not fully understood, as the ligands for these receptors are largely unidentified. In this study, we report that KIR2DS2 reporter cells recognize a ligand expressed by cancer cell lines. All cancer targets recognized by KIR2DS2 were also recognized by KIR2DL2 and KIR2DL3 reporters. Trogocytosis of membrane proteins from the cancer targets was observed with responding reporter cells, indicating the formation of KIR2DS2 ligand-specific immunological synapses...
April 1, 2017: Journal of Immunology: Official Journal of the American Association of Immunologists
Justin S A Perry, Kodi S Ravichandran
New work in Caenorhabditis elegans shows that during embryogenesis endodermal cells interact with and regulate primordial germ cells by actively excising and digesting germ cell lobes. Endodermal cells utilize proteins linked to endocytosis to perform this unique 'cannibalistic' process.
January 23, 2017: Current Biology: CB
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