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Agbakwuru D, Wetzel SA. The Biological Significance of Trogocytosis. Results Probl Cell Differ 2024; 73:87-129. [PMID: 39242376 DOI: 10.1007/978-3-031-62036-2_5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/09/2024]
Abstract
Trogocytosis is the intercellular transfer of membrane and membrane-associated proteins between cells. Trogocytosis is an underappreciated phenomenon that has historically routinely been dismissed as an artefact. With a greater understanding of the process and the implications it has on biological systems, trogocytosis has the potential to become a paradigm changer. The presence on a cell of molecules they don't endogenously express can alter the biological activity of the cell and could also lead to the acquisition of new functions. To better appreciate this phenomenon, it is important to understand how these intercellular membrane exchanges influence the function and activity of the donor and the recipient cells. In this chapter, we will examine how the molecules acquired by trogocytosis influence the biology of a variety of systems including mammalian fertilization, treatment of hemolytic disease of the newborn, viral and parasitic infections, cancer immunotherapy, and immune modulation.
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Affiliation(s)
- Deborah Agbakwuru
- Center for Environmental Health Sciences, University of Montana, Missoula, MT, USA
| | - Scott A Wetzel
- Center for Environmental Health Sciences, University of Montana, Missoula, MT, USA.
- Division of Biological Sciences, University of Montana, Missoula, MT, USA.
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2
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Martinez-Martin N, Alarcon B. Physiological and therapeutic relevance of T cell receptor-mediated antigen trogocytosis. Biomed J 2023; 47:100630. [PMID: 37459965 DOI: 10.1016/j.bj.2023.100630] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2023] [Accepted: 07/12/2023] [Indexed: 08/31/2024] Open
Abstract
Trogocytosis is an active process whereby fragments of plasma membrane proteins and cytoplasm are transferred from one cell to another in a cell-cell contact-dependent manner. T cells trogocytose pieces of the cells presenting antigen to them at the site of the immunological synapse. Fragments of the antigen-presenting cell membrane rich in antigen/major histocompatibility (MHC) complexes are internalized by the T cell. Those complexes are redirected to the plasma membrane of the T cell, which subsequently becomes an antigen-presenting cell to other T cells. Removing antigen/MHC complexes from professional and tumoral cells has consequences for the intensity and duration of the immune response. However, the acquired capacity of T cells to present the trogocytosed cognate antigen/MHC complexes also affects the properties of the trogocytotic T cells. Acting as antigen-presenting cells, trogocytotic CD4 T cells influence both the differentiation of cytotoxic T cells and the differentiation of other CD4 T cells into pro-inflammatory effector T cells. Furthermore, trogocytosis of antigen/MHC complexes promotes the differentiation of the trogocytotic CD4 T cells towards regulatory T cells and Th2 effector cells. Trogoctyosis is, therefore, a parallel mechanism to signal transduction by membrane receptors, including the T cell antigen receptor, at the plane of the plasma membrane.
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Affiliation(s)
- Nuria Martinez-Martin
- Centro de Biología Molecular Severo Ochoa, Consejo Superior de Investigaciones Científicas, Universidad Autónoma de Madrid, Madrid, Spain
| | - Balbino Alarcon
- Centro de Biología Molecular Severo Ochoa, Consejo Superior de Investigaciones Científicas, Universidad Autónoma de Madrid, Madrid, Spain.
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Reed J, Reichelt M, Wetzel SA. Lymphocytes and Trogocytosis-Mediated Signaling. Cells 2021; 10:1478. [PMID: 34204661 PMCID: PMC8231098 DOI: 10.3390/cells10061478] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2021] [Revised: 06/07/2021] [Accepted: 06/10/2021] [Indexed: 12/21/2022] Open
Abstract
Trogocytosis is the intercellular transfer of membrane and membrane-associated molecules. This underappreciated process has been described in a variety of biological settings including neuronal remodeling, fertilization, viral and bacterial spread, and cancer, but has been most widely studied in cells of the immune system. Trogocytosis is performed by multiple immune cell types, including basophils, macrophages, dendritic cells, neutrophils, natural killer cells, B cells, γδ T cells, and CD4+ and CD8+ αβ T cells. Although not expressed endogenously, the presence of trogocytosed molecules on cells has the potential to significantly impact an immune response and the biology of the individual trogocytosis-positive cell. Many studies have focused on the ability of the trogocytosis-positive cells to interact with other immune cells and modulate the function of responders. Less understood and arguably equally important is the impact of these molecules on the individual trogocytosis-positive cell. Molecules that have been reported to be trogocytosed by cells include cognate ligands for receptors on the individual cell, such as activating NK cell ligands and MHC:peptide. These trogocytosed molecules have been shown to interact with receptors on the trogocytosis-positive cell and mediate intracellular signaling. In this review, we discuss the impact of this trogocytosis-mediated signaling on the biology of the individual trogocytosis-positive cell by focusing on natural killer cells and CD4+ T lymphocytes.
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Affiliation(s)
- Jim Reed
- Division of Biological Sciences, University of Montana, Missoula, MT 59812, USA; (J.R.); (M.R.)
| | - Madison Reichelt
- Division of Biological Sciences, University of Montana, Missoula, MT 59812, USA; (J.R.); (M.R.)
| | - Scott A. Wetzel
- Division of Biological Sciences, University of Montana, Missoula, MT 59812, USA; (J.R.); (M.R.)
- Center for Environmental Health Sciences, University of Montana, Missoula, MT 59812, USA
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4
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IL-10 gene-modified dendritic cells-induced type 1 T regulatory cells inhibit graft-versus-host disease while preserving graft-versus-leukemia effect. Biochem Biophys Res Commun 2018; 507:122-127. [DOI: 10.1016/j.bbrc.2018.10.183] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2018] [Accepted: 10/29/2018] [Indexed: 11/22/2022]
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Umeshappa CS, Xie Y, Xu S, Nanjundappa RH, Freywald A, Deng Y, Ma H, Xiang J. Th cells promote CTL survival and memory via acquired pMHC-I and endogenous IL-2 and CD40L signaling and by modulating apoptosis-controlling pathways. PLoS One 2013; 8:e64787. [PMID: 23785406 PMCID: PMC3681805 DOI: 10.1371/journal.pone.0064787] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2012] [Accepted: 04/17/2013] [Indexed: 11/18/2022] Open
Abstract
Involvement of CD4+ helper T (Th) cells is crucial for CD8+ cytotoxic T lymphocyte (CTL)-mediated immunity. However, CD4+ Th’s signals that govern CTL survival and functional memory are still not completely understood. In this study, we assessed the role of CD4+ Th cells with acquired antigen-presenting machineries in determining CTL fates. We utilized an adoptive co-transfer into CD4+ T cell-sufficient or -deficient mice of OTI CTLs and OTII Th cells or Th cells with various gene deficiencies pre-stimulated in vitro by ovalbumin (OVA)-pulsed dendritic cell (DCova). CTL survival was kinetically assessed in these mice using FITC-anti-CD8 and PE-H-2Kb/OVA257-264 tetramer staining by flow cytometry. We show that by acting via endogenous CD40L and IL-2, and acquired peptide-MHC-I (pMHC-I) complex signaling, CD4+ Th cells enhance survival of transferred effector CTLs and their differentiation into the functional memory CTLs capable of protecting against highly-metastasizing tumor challenge. Moreover, RT-PCR, flow cytometry and Western blot analysis demonstrate that increased survival of CD4+ Th cell-helped CTLs is matched with enhanced Akt1/NF-κB activation, down-regulation of TRAIL, and altered expression profiles with up-regulation of prosurvival (Bcl-2) and down-regulation of proapoptotic (Bcl-10, Casp-3, Casp-4, Casp-7) molecules. Taken together, our results reveal a previously unexplored mechanistic role for CD4+ Th cells in programming CTL survival and memory recall responses. This knowledge could also aid in the development of efficient adoptive CTL cancer therapy.
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Affiliation(s)
| | - Yufeng Xie
- Cancer Research Unit, Saskatchewan Cancer Agency, Saskatoon, Saskatchewan, Canada
| | - Shulin Xu
- Cancer Research Unit, Saskatchewan Cancer Agency, Saskatoon, Saskatchewan, Canada
| | | | - Andrew Freywald
- Department of Pathology, University of Saskatchewan, Saskatoon, Saskatchewan, Canada
| | - Yulin Deng
- School of Life Science, Beijing Institute of Technology, Beijing, China
| | - Hong Ma
- School of Life Science, Beijing Institute of Technology, Beijing, China
| | - Jim Xiang
- Cancer Research Unit, Saskatchewan Cancer Agency, Saskatoon, Saskatchewan, Canada
- * E-mail:
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Ahmed KA, Wang L, Munegowda MA, Mulligan SJ, Mulligan S, Gordon JR, Griebel P, Xiang J. Direct in vivo evidence of CD4+ T cell requirement for CTL response and memory via pMHC-I targeting and CD40L signaling. J Leukoc Biol 2012; 92:289-300. [PMID: 22544940 DOI: 10.1189/jlb.1211631] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023] Open
Abstract
CD4(+) T cell help contributes critically to DC-induced CD8(+) CTL immunity. However, precisely how these three cell populations interact and how CD4(+) T cell signals are delivered to CD8(+) T cells in vivo have been unclear. In this study, we developed a novel, two-step approach, wherein CD4(+) T cells and antigen-presenting DCs productively engaged one another in vivo in the absence of cognate CD8(+) T cells, after which, we selectively depleted the previously engaged CD4(+) T cells or DCs before allowing interactions of either population alone with naïve CD8(+) T cells. This protocol thus allows us to clearly document the importance of CD4(+) T-licensed DCs and DC-primed CD4(+) T cells in CTL immunity. Here, we provide direct in vivo evidence that primed CD4(+) T cells or licensed DCs can stimulate CTL response and memory, independent of DC-CD4(+) T cell clusters. Our results suggest that primed CD4(+) T cells with acquired pMHC-I from DCs represent crucial "immune intermediates" for rapid induction of CTL responses and for functional memory via CD40L signaling. Importantly, intravital, two-photon microscopy elegantly provide unequivocal in vivo evidence for direct CD4-CD8(+) T cell interactions via pMHC-I engagement. This study corroborates the coexistence of direct and indirect mechanisms of T cell help for a CTL response in noninflammatory situations. These data suggest a new "dynamic model of three-cell interactions" for CTL immunity derived from stimulation by dissociated, licensed DCs, primed CD4(+) T cells, and DC-CD4(+) T cell clusters and may have significant implications for autoimmunity and vaccine design.
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Affiliation(s)
- Khawaja Ashfaque Ahmed
- Research Unit, Saskatchewan Cancer Agency, Department of Oncology, University of Saskatchewan, Saskatoon, Saskatchewan Canada
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Ankathatti Munegowda M, Xu S, Freywald A, Xiang J. CD4+ Th2 cells function alike effector Tr1 and Th1 cells through the deletion of a single cytokine IL-6 and IL-10 gene. Mol Immunol 2012; 51:143-9. [PMID: 22424785 DOI: 10.1016/j.molimm.2012.02.120] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2011] [Revised: 02/17/2012] [Accepted: 02/21/2012] [Indexed: 01/14/2023]
Abstract
Depending on polarizing cytokine signals during activation by antigen, naïve CD4+ T cells can be stimulated and differentiated into distinct functional CD4+ T cell subsets such as Th1, Th2 and Tr1 cells. Among them, Th2 cells are pathogenic in allergic diseases such as asthma, which are characterized by transcription factor GATA3 expression and IL-4, IL-5, IL-6, and IL-10 cytokine secretion. The overlapping expression of some signature cytokines by Th2 and other subsets of CD4+ T cells may not only indicate the plasticity of CD4+ T cells, but could also suggest the possibility of the deletion of a single signature cytokine gene leading to the functional differentiation of naïve CD4+ T cells into effector Th1 or Tr1 cells under Th2 differentiation conditions. In this work, we stimulated naïve CD4+ T cells derived from OT II mice or OT II mice that were deficient in individual cytokines (IL-4, IL-5, IL-6 and IL-10) with OVA-pulsed dendritic cells (DC(OVA)) in the presence of IL-4 and anti-IFN-γ, to generate OVA-specific wild-type (WT) Th2, and Th2(IL-4 KO), or Th2(IL-5 KO), or Th2(IL-6 KO), or Th2(IL-10 KO) cells, and to assess their capacity in modulating DC(OVA)-induced CD8+ cytotoxic T lymphocyte (CTL) responses, and antitumor immunity in WT C57BL/6 mice. We conclusively demonstrate that GATA-3-expressing Th2 cells enhance DC(OVA)-induced CTL responses via IL-6 secretion. We also show that IL-6 and IL-10 gene deficient Th2(IL-6 KO) and Th2(IL-10 KO) cells, but not IL-4 and IL-5 gene deficient Th2(IL-4 KO) and Th2(IL-5 KO) cells, behave like functional Tr1 and Th1 cells by inhibiting and enhancing DC(OVA)-induced OVA-specific CD8+ CTL responses and antitumor immunity, respectively. We further elucidate that inhibition and enhancement of DC(OVA)-induced OVA-specific CTL responses by Th2(IL-6 KO) and Th2(IL-10 KO) cells are mediated by their immune suppressive IL-10 and pro-inflammatory IL-6 secretion, respectively. Taken together, our study suggests that deletion of a single cytokine gene IL-6 and IL-10 makes CD4+ Th2 cells become effector CD4+ Tr1- and Th1-like cells, respectively. Our data thus not only provide new evidence for another type of CD4+ T cell plasticity, but also have a potential to impact the development of a new direction in immunotherapy of allergic diseases.
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Affiliation(s)
- Manjunatha Ankathatti Munegowda
- Cancer Research Unit, Research Division, Saskatchewan Cancer Agency, Departments of Oncology and Pathology, University of Saskatchewan, Saskatoon, Saskatchewan, Canada
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8
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Zhou G, Ding ZC, Fu J, Levitsky HI. Presentation of acquired peptide-MHC class II ligands by CD4+ regulatory T cells or helper cells differentially regulates antigen-specific CD4+ T cell response. THE JOURNAL OF IMMUNOLOGY 2011; 186:2148-55. [PMID: 21242518 DOI: 10.4049/jimmunol.1002917] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Activated T cells can acquire membrane molecules from APCs through a process termed trogocytosis. The functional consequence of this event has been a subject of debate. Focusing on transfer of peptide-MHC class II (MHC-II) complexes from APCs to CD4(+) T cells after activation, in this study we investigated the molecule acquisition potential of naturally occurring regulatory T cells (Tregs) and CD4(+) Th cells. We show that acquisition of membrane molecules from APCs is an inherent feature of CD4(+) T cell activation. Triggering of the TCR enables CD4(+) T cells to acquire their agonist ligands as well as other irrelevant membrane molecules from the interacting APCs or bystander cells in a contact-dependent manner. Notably, trogocytosis is a continuous process during cell cycle progression, and Th cells and Tregs have comparable capacity for trogocytosis both in vitro and in vivo. The captured peptide-MHC-II molecules, residing in sequestered foci on the host cell surface, endow the host cells with Ag-presenting capability. Presentation of acquired peptide-MHC-II ligands by Th cells or Tregs has either stimulatory or regulatory effect on naive CD4(+) T cells, respectively. Furthermore, Th cells with captured peptide-MHC-II molecules become effector cells that manifest better recall responses, and Tregs with captured ligands exhibit enhanced suppression activity. These findings implicate trogocytosis in different subsets of CD4(+) T cells as an intrinsic mechanism for the fine tuning of Ag-specific CD4(+) T cell response.
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Affiliation(s)
- Gang Zhou
- Cancer Immunotherapy Program, Medical College of Georgia Cancer Center, Medical College of Georgia, Augusta, GA 30912, USA.
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Toda M, Wang L, Ogura S, Torii M, Kurachi M, Kakimi K, Nishikawa H, Matsushima K, Shiku H, Kuribayashi K, Kato T. UV irradiation of immunized mice induces type 1 regulatory T cells that suppress tumor antigen specific cytotoxic T lymphocyte responses. Int J Cancer 2011; 129:1126-36. [PMID: 21710495 DOI: 10.1002/ijc.25775] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2010] [Accepted: 10/22/2010] [Indexed: 01/11/2023]
Abstract
We previously showed that exposure to UV radiation after immunization suppresses Th1 and Th2 immune responses, leading to impaired Ab and allo-immune responses, but the impact of UV radiation after immunization on anti-tumor immune responses mediated by tumor-specific CD8(+) T cell responses remains less clear. Furthermore, the exact phenotypic and functional characteristics of regulatory T cell population responsible for the UV-induced immunosuppression still remain elusive. Using the MBL-2 lymphoma cell line engineered to express OVA as a surrogate tumor Ag, here we demonstrate that UV irradiation after tumor Ag-immunization suppresses the anti-tumor immune response in a manner dependent on the immunizing Ag. This suppression was mediated by interleukin (IL)-10 released from CD4(+) CD25(+) T cells, by which impaired the induction of cytotoxic T lymphocytes (CTL) able to kill Ag-expressing tumor cells. In addition, we generated a panel of T cell clones from UV-irradiated and non-irradiated mice, and all of the clones derived from UV-irradiated mice had a Tr1-type regulatory T cell phenotype with expression of IL-10 and c-Maf, but not Foxp3. These Tr1-type regulatory T cell clones suppressed tumor rejection in vivo as well as Th cell activation in vitro in an IL-10 dependent manner. Given that suppression of Ag-specific CTL responses can be induced in Ag-sensitized mice by UV irradiation, our results may imply that exposure to UV radiation during premalignant stage induces tumor-Ag specific Tr1 cells that mediate tumor-Ag specific immune suppression resulting in the promotion of tumor progression.
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Affiliation(s)
- Masaaki Toda
- Department of Cellular and Molecular Immunology, Mie Graduate School of Medicine, Tsu, Japan
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Hwang I, Ki D. Receptor-mediated T cell absorption of antigen presenting cell-derived molecules. FRONT BIOSCI-LANDMRK 2011; 16:411-21. [PMID: 21196178 DOI: 10.2741/3695] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
T cells tend to acquire a variety of cell surface molecules derived from antigen presenting cells (APCs). The molecule uptake occurs mainly during direct T/APC contact and is instigated by specific receptor/ligand interactions, such as T cell receptor (TCR) with a cognate peptide/MHC complex (pMHC) or CD28 with B7. The acquired molecules are targeted for internalization and degradation in the lysosome. Nevertheless, those molecules are expressed on the surface of T cells for a period of time. The presentation of APC-derived ligands by T cells exhibited a multitude of immunological effects via antigen-specific T/T interaction upon recognition of the absorbed antigens by contact with other T cells. Ligand uptake also occurs via absorption of membrane vesicles shed from APCs prior to contact (e.g., exosomes and plasma membrane-derived vesicles). As in ligand absorption via direct T/APC interaction, the absorption of pre-formed membrane vesicles is also dependent on specific receptor/ligand interactions. In this review, biological mechanisms underlying the ligand absorption process as well as the biological significance and application of the event will be discussed.
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Affiliation(s)
- Inkyu Hwang
- Department of Chemistry and Chemical Biology, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, California 92037, USA.
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11
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Brown K, Fidanboylu M, Wong W. Intercellular exchange of surface molecules and its physiological relevance. Arch Immunol Ther Exp (Warsz) 2010; 58:263-72. [PMID: 20508995 DOI: 10.1007/s00005-010-0085-y] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2009] [Accepted: 02/11/2010] [Indexed: 12/31/2022]
Abstract
For many decades, cellular immunologists have relied on the expression of various cell surface molecules to divide cells into different types and subtypes to study their function. However, in recent years, a large and fast-expanding body of work has described the transfer of surface molecules, including MHC class I and II molecules, between cells, both in vitro and in vivo. The function of this process is still largely unknown, but it is likely to have a significant role in the control of the immune system. It is also likely that this process takes place in a regulated rather than stochastic manner, thus providing another way for the immune system to orchestrate its function. In this review we will summarize the key findings so far, examining the mechanisms of transfer, the consequences of this transfer as shown by in vitro experiments, and possible consequences for the wider immune response.
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Affiliation(s)
- Kathryn Brown
- MRC Centre for Transplantation, King's College London, School of Medicine at Guy's, King's and St. Thomas' Hospitals, London, UK
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12
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Abstract
In a multicellular system, cellular communication is a must for orchestration and coordination of cellular events. Advent of the latest analytical and imaging tools has allowed us to enhance our understanding of the intercellular communication. An intercellular exchange of proteins or intact membrane patches is a ubiquitous phenomenon, and has been the subject of renewed interest, particularly in the context of immune cells. Recent evidence implicates that intercellular protein transfers, including trogocytosis is an important mechanism of the immune system to modulate immune responses and transferred proteins can also contribute to pathology. It has been demonstrated that intercellular protein transfer can be through the internalization/pathway, dissociation-associated pathway, uptake of exosomes and membrane nanotube formations. Exchange of membrane molecules/antigens between immune cells has been observed for a long time, but the mechanisms and functional consequences of these transfers remain unclear. In this review, we will discuss the important findings concerning intercellular protein transfers, possible mechanisms and highlight their physiological relevance to the immune system, with special reference to T cells such as the stimulatory or suppressive immune responses derived from T cells with acquired dendritic cell membrane molecules.
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Affiliation(s)
- Khawaja Ashfaque Ahmed
- Research Unit, Saskatchewan Cancer Agency, Departments of Oncology, Microbiology and Immunology, College of Medicine, University of Saskatchewan, Saskatoon, SK, Canada
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Li X, Yang A, Huang H, Zhang X, Town J, Davis B, Cockcroft DW, Gordon JR. Induction of type 2 T helper cell allergen tolerance by IL-10-differentiated regulatory dendritic cells. Am J Respir Cell Mol Biol 2009; 42:190-9. [PMID: 19372244 DOI: 10.1165/rcmb.2009-0023oc] [Citation(s) in RCA: 60] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
In mouse models of asthma, therapeutic use of allergen-presenting IL-10-differentiated dendritic cells (DCs) can abrogate airway hyperresponsiveness, and reduce other asthma-related responses to near background. Analogous human DCs can suppress human T cell responses in vitro, but the operative mechanisms are poorly defined. We investigated the ability of IL-10-treated human DCs to induce tolerance among autologous T cells of subjects with asthma and the mechanisms by which they do this. CD14(+) monocyte-derived DCs were differentiated in the presence of IL-10 (DC10) ex vivo from 11 donors with asthma and 4 control donors, and characterized for relevant markers. They were pulsed with specific or irrelevant allergen, and cultured with autologous peripheral blood CD4(+) T cells, either alone or together with autologous immunostimulatory DCs (DC-TNF), and the impact of this treatment on the T-cell responses was assessed for each donor. The DC10 expressed reduced levels of some relevant markers (CD40, CD80, human leukocyte antigen-DR) and stimulatory cytokines (IL-6 and IL-12), but augmented levels of Ig-like transcript-22/CD85j and IL-10 relative to DC-TNF. In cocultures, they dampened DC-TNF-driven T helper (Th) type 2 cell proliferation and cytokine (IL-4, -5, and -13) secretion. They also drove the development from atopic CD4(+)CD25(lo)Foxp3(lo) cells of a population of IL-10-secreting CD25(+)Foxp3(+)LAG-3(+)CTLA-4(+) regulatory T cells (Tregs). These Tregs suppressed stimulatory DC-induced autologous Th2 cell proliferation and cytokine secretion in a contact-dependent manner. Our data indicate that IL-10-treated human DCs induce Th2 cell allergen tolerance ex vivo by driving the differentiation of Tregs.
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Affiliation(s)
- Xiuling Li
- Department of Veterinary Microbiology, University of Saskatchewan, Saskatoon, Canada
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