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Dendritic Cell and Macrophage Nomenclature and Classification

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Book Series: Frontiers Research Topics ISSN: 16648714 ISBN: 9782889199181 Year: Pages: 202 DOI: 10.3389/978-2-88919-918-1 Language: English
Publisher: Frontiers Media SA
Subject: Medicine (General) --- Allergy and Immunology
Added to DOAB on : 2016-01-19 14:05:46
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The mononuclear phagocyte system (MPS) comprises dendritic cells (DCs), monocytes and macrophages (MØs) that together play crucial roles in tissue immunity and homeostasis, but also contribute to a broad spectrum of pathologies. They are thus attractive therapeutic targets for immune therapy. However, the distinction between DCs, monocytes and MØ subpopulations has been a matter of controversy and the current nomenclature has been a confounding factor. DCs are remarkably heterogeneous and consist of multiple subsets traditionally defined by their expression of various surface markers. While markers are important to define various populations of the MPS, they do not specifically define the intrinsic nature of a cell population and do not always segregate a bona fide cell type of relative homogeneity. Markers are redundant, or simply define distinct activation states within one subset rather than independent subpopulations. One example are the steady-state CD11b+ DCs which are often not distinguished from monocytes, monocyte-derived cells, and macrophages due to their overlapping phenotype. Lastly, monocyte fate during inflammation results in cells bearing the phenotypic and functional features of both DCs and MØs significantly adding to the confusion. In fact, depending on the context of the study and the focus of the laboratory, a monocyte-derived cell will be either be called "monocyte-derived DCs" or "macrophages". Because the names we give to cells are often associated with a functional connotation, this is much more than simple semantics. The "name" we give to a population fundamentally changes the perception of its biology and can impact on research design and interpretation. Recent evidence in the ontogeny and transcriptional regulation of DCs and MØs, combined with the identification of DC- and MØ-specific markers has dramatically changed our understanding of their interrelationship in the steady state and inflammation. In steady state, DCs are constantly replaced by circulating blood precursors that arise from committed progenitors in the bone marrow. Similarly, some MØ populations are also constantly replaced by circulating blood monocytes. However, others tissue MØs are derived from embryonic precursors, are seeded before birth and maintain themselves in adults by self-renewal. In inflammation, such differentiation pathways are fundamentally changed and unique monocyte-derived inflammatory cells are generated. Current DC, monocyte and MØ nomenclature does not take into account these new developments and as a consequence is quite confusing. We believe that the field is in need of a fresh view on this topic as well as an upfront debate on DC and MØ nomenclature. Our aim is to bring expert junior and senior scientists to revisit this topic in light of these recent developments. This Research Topic will cover all aspects of DC, monocyte and MØ biology including development, transcriptional regulation, functional specializations, in lymphoid and non-lymphoid tissues, and in both human and mouse models. Given the central position of DCs, monocytes and MØs in tissue homeostasis, immunity and disease, this topic should be of interest to a large spectrum of the biomedical community.

Harnessing oncolytic virus-mediated immunity

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Book Series: Frontiers Research Topics ISSN: 16648714 ISBN: 9782889194506 Year: Pages: 110 DOI: 10.3389/978-2-88919-450-6 Language: English
Publisher: Frontiers Media SA
Subject: Oncology --- Allergy and Immunology --- Medicine (General)
Added to DOAB on : 2016-02-05 17:24:33
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Oncolytic viruses (OVs) have emerged as a promising anticancer treatment. OVs selectively infect, replicate in, and kill tumor cells. Oncolytic viral therapy occurs in two phases: an initial phase where the virus mediates direct oncolysis of tumor cells, and a second phase where an induced post-oncolytic immune response continues to mediate tumor destruction and retards progression of the disease. For a long time, the therapeutic efficacy was thought to depend mainly on the direct viral oncolysis based on their tumor selective replication and killing activities. But the post-oncolytic anti-tumor activity induced by the OV therapy is also a key factor for an efficient therapeutic activity. The topic adresses various strategies how to optimize OVs anti-tumor activity.

Innate Immune Cell Determinants of T Cell Immunity: From Basic Mechanisms to Clinical Implications

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Book Series: Frontiers Research Topics ISSN: 16648714 ISBN: 9782889199075 Year: Pages: 143 DOI: 10.3389/978-2-88919-907-5 Language: English
Publisher: Frontiers Media SA
Subject: Medicine (General) --- Allergy and Immunology
Added to DOAB on : 2016-01-19 14:05:46
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Long-lasting T cell immunity is delivered by an array of individual T lymphocytes expressing clonally distributed and highly specific antigen receptors recognizing an almost infinite number of antigens that might enter in contact with the host. Following antigen-specific priming in lymphnodes, naïve CD4 and CD8 T lymphocytes proliferate generating clones of effector cells that migrate to peripheral tissues and deliver unique antigen-specific effector functions. Moreover, a proportion of these effector lymphocytes survive as memory T cells that can be rapidly mobilized upon new exposure to the same antigen, even years after their primary induction. Innate immune cells play crucial roles in the induction and maintenance of this efficient protection system. Following the seminal discovery of Steinman and Cohen in 1974 describing a rare cell type capable of initiating antigen-specific responses in lymphnodes, Dendritic Cells (DC) have taken up the stage for several decades as professional Antigen Presenting Cells (APC). Although DC possess all attributes to prime naïve T lymphocytes, other immune cell subsets become crucial accessory cells during secondary and even primary activation. For instance, Monocytes (Mo) are rapidly recruited to inflammatory sites and have recently been recognized as capable of shaping T cell immunity, either directly through Ag presentation, or indirectly through the secretion of soluble factors. In addition, upon sensing of T cell-derived cytokines, Mo differentiate into functionally different APC types that further impact on the quality and persistence of memory T cell responses in peripheral tissues. Other innate immune cells, including Myeloid Derived Suppressor Cells, Granulocytes and iNKT lymphocytes, are known to modulate T cell activation by interacting with and modifying the function of professional APC. Notably, innate immune cell determinants also account for the tissue-specific regulation of T cell immunity. Hence, the newly discovered family of Innate Lymphoid Cells, has been recognized to shape CD4+ T cell responses at mucosal surfaces. Although the actions of innate immune cells fulfills the need of initiating and maintaining protective T cell responses, the excessive presence or activity of individual determinants may be detrimental to the host, because it could promote tissue destruction as in autoimmunity and allergy, or conversely, prevent the induction of immune responses against malignant tissues, and even modulate the response to therapeutic agents. Thus, understanding how defined innate immune cell subsets control T cell immunity is of fundamental relevance to understand human health, and of practical relevance for preventing and curing human diseases. In this research topic, we intend to provide an excellent platform for the collection of manuscripts addressing in depth how diverse innate immune cell subsets impact on T cell responses through molecularly defined pathways and evaluating the rational translation of basic research into clinical applications.

Bacterial Exotoxins: How bacteria fight the immune system

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Book Series: Frontiers Research Topics ISSN: 16648714 ISBN: 9782889199914 Year: Pages: 190 DOI: 10.3389/978-2-88919-991-4 Language: English
Publisher: Frontiers Media SA
Subject: Microbiology --- Science (General) --- Allergy and Immunology --- Medicine (General)
Added to DOAB on : 2016-01-19 14:05:46
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The goal of this research topic was to gather current knowledge on the interaction of bacterial exotoxins and effector proteins with the host immune system. The following 16 research and review articles in this special issue describe mechanisms of immune modification and evasion and provide an overview over the complexity of bacterial toxin interaction with different cells of the immune system.

Tertiary Lymphoid Organs (TLOs): Powerhouses of Disease Immunity

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Book Series: Frontiers Research Topics ISSN: 16648714 ISBN: 9782889451807 Year: Pages: 235 DOI: 10.3389/978-2-88945-180-7 Language: English
Publisher: Frontiers Media SA
Subject: Allergy and Immunology --- Medicine (General)
Added to DOAB on : 2017-08-28 14:01:09
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The immune system employs TLOs to elicit highly localized and forceful responses to unresolvable peripheral tissue inflammation. Current data indicate that TLOs are protective but they may also lead to collateral tissue injury and serve as nesting places to generate autoreactive lymphocytes. A better comprehension of these powerhouses of disease immunity will likely facilitate development to unprecedented and specific therapies to fight chronic inflammatory diseases.

Tailoring NK Cell Receptor-Ligand Interactions: An Art in Evolution

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Book Series: Frontiers Research Topics ISSN: 16648714 ISBN: 9782889454648 Year: Pages: 407 DOI: 10.3389/978-2-88945-464-8 Language: English
Publisher: Frontiers Media SA
Subject: Medicine (General) --- Allergy and Immunology
Added to DOAB on : 2018-11-16 17:17:57
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Recognition and killing of aberrant, infected or tumor targets by Natural Killer (NK) cells is mediated by positive signals transduced by activating receptors upon engagement of ligands on target surface. These stimulatory pathways are counterbalanced by inhibitory receptors that raise NK cell activation threshold through negative antagonist signals. While regulatory effects are necessary for physiologic control of autoimmune aggression, they may restrain the ability of NK cells to activate against disease. Overcoming this barrier to immune surveillance, multiple approaches to enhance NK-mediated responses are being investigated since two decades. Propelled by considerable advances in the understanding of NK cell biology, these studies are critical for effective translation of NK-based immunotherapy principles into the clinic. In humans, dominant inhibitory signals are transduced by Killer Immunoglobulin Like Receptors (KIR) recognizing cognate HLA class I on target cells. Conversely, KIR recognition of “missing self-HLA” - due to HLA loss or HLA/ KIR mismatch - triggers NK-mediated tumor rejection. Initially observed in murine transplant models, these antitumor effects were later found to have important implications for the clinical outcome of haplotype-mismatched stemcell transplantation. Here, donor NK subsets protect against acute myeloid leukemia (AML) relapse through missing self recognition of donor HLA-C allele groups (C1 or C2) and/or Bw4 epitope. These studies were subsequently extended by trials investigating the antileukemia effects of adoptively transferred haplotype-mismatched NK cells in non-transplant settings. Other mechanisms have been found to induce clinically relevant NK cell alloreactivity in transplantation, e.g., post-reconstitution functional reversal of anergic NK cells. More recently, activating KIR came into the spotlight for their potential ability to directly activate donor NK cells through in vivo recognition of HLA or other ligands. Novel therapeutic monoclonal antibodies (mAb) may optimize NK-mediated effects. Examples include obinutuzumab (GA101), a glyco-engineered anti-CD20 mAb with increased affinity for the FcγRIIIA receptor, enhancing antibody-dependent cellular cytotoxicity; lirilumab (IPH2102), a first-in-class NK-specific checkpoint inhibitor, blocking the interaction between the major KIR and cognate HLA-C antigens; and elotuzumab (HuLuc63), a humanized monoclonal antibody specific for SLAMF7, whose anti-myeloma therapeutic effects are partly due to direct activation of SLAMF7-expressing NK cells. In addition to conventional antibodies, NK cell-targeted bispecific (BiKEs) and trispecific (TriKEs) killer engagers have also been developed. These proteins elicit potent effector functions by binding target ligands (e.g., CD19, CD22, CD30, CD133, HLA class II, EGFR) on one arm and NK receptors on the other. An additional innovative approach to direct NK cell activity is genetic reprogramming with chimeric antigen receptors (CAR). To date, primary NK cells and the NK92 cell line have been engineered with CAR specific for antigens expressed on multiple tumors. Encouraging preclinical results warrant further development of this approach. This Research Topic welcomes contributions addressing mechanisms of NK-mediated activation in response to disease as well as past and contemporary strategies to enhance NK mediated reactivity through control of the interactions between NK receptors and their ligands.

Immunotherapy for Tumor in the Brain: Insights From - and For - Other Tumor Sites

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Book Series: Frontiers Research Topics ISSN: 16648714 ISBN: 9782889455355 Year: Pages: 95 DOI: 10.3389/978-2-88945-535-5 Language: English
Publisher: Frontiers Media SA
Subject: Medicine (General) --- Oncology
Added to DOAB on : 2019-01-23 14:53:42
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Tumor immunotherapy has now shown its promise for many, its disappointments and failings for others. Going forward, brain tumor patients can both benefit and contribute.Tumor immunotherapy is steadily progressing. As experience accumulates, it is important to consider its generality. The reviews herein emphasize the brain’s place among other tumor sites. Two major topics are addressed.THE SITE: WHAT CAN WE EXPECT FROM IMMUNOTHERAPY WHEN THE TARGET IS IN THE BRAIN?Experience with immunotherapy for different targets in the brain, including tumor and also pathogens, is reviewed. Long-standing assumptions are confronted. The potential for beneficial responses is stressed.BRAIN TUMOR IMMUNOTHERAPY: WHAT HAVE WE LEARNED SO FAR?Clinical experience with brain tumor immunotherapy, from a variety of centers, is reviewed. Primary tumors, emphasizing glioblastoma, and brain metastases are each considered.

Tailoring NK Cell Receptor-Ligand Interactions: an Art in Evolution. 2nd Edition

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Book Series: Frontiers Research Topics ISSN: 16648714 ISBN: 9782889456635 Year: Pages: 407 DOI: 10.3389/978-2-88945-663-5 Language: English
Publisher: Frontiers Media SA
Subject: Medicine (General) --- Allergy and Immunology
Added to DOAB on : 2019-01-23 14:53:43
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Recognition and killing of aberrant, infected or tumor targets by Natural Killer (NK) cells is mediated by positive signals transduced by activating receptors upon engagement of ligands on target surface. These stimulatory pathways are counterbalanced by inhibitory receptors that raise NK cell activation threshold through negative antagonist signals. While regulatory effects are necessary for physiologic control of autoimmune aggression, they may restrain the ability of NK cells to activate against disease. Overcoming this barrier to immune surveillance, multiple approaches to enhance NK-mediated responses are being investigated since two decades. Propelled by considerable advances in the understanding of NK cell biology, these studies are critical for effective translation of NK-based immunotherapy principles into the clinic. In humans, dominant inhibitory signals are transduced by Killer Immunoglobulin Like Receptors (KIR) recognizing cognate HLA class I on target cells. Conversely, KIR recognition of “missing self-HLA” - due to HLA loss or HLA/ KIR mismatch - triggers NK-mediated tumor rejection. Initially observed in murine transplant models, these antitumor effects were later found to have important implications for the clinical outcome of haplotype-mismatched stemcell transplantation. Here, donor NK subsets protect against acute myeloid leukemia (AML) relapse through missing self recognition of donor HLA-C allele groups (C1 or C2) and/or Bw4 epitope. These studies were subsequently extended by trials investigating the antileukemia effects of adoptively transferred haplotype-mismatched NK cells in non-transplant settings. Other mechanisms have been found to induce clinically relevant NK cell alloreactivity in transplantation, e.g., post-reconstitution functional reversal of anergic NK cells. More recently, activating KIR came into the spotlight for their potential ability to directly activate donor NK cells through in vivo recognition of HLA or other ligands. Novel therapeutic monoclonal antibodies (mAb) may optimize NK-mediated effects. Examples include obinutuzumab (GA101), a glyco-engineered anti-CD20 mAb with increased affinity for the FcγRIIIA receptor, enhancing antibody-dependent cellular cytotoxicity; lirilumab (IPH2102), a first-in-class NK-specific checkpoint inhibitor, blocking the interaction between the major KIR and cognate HLA-C antigens; and elotuzumab (HuLuc63), a humanized monoclonal antibody specific for SLAMF7, whose anti-myeloma therapeutic effects are partly due to direct activation of SLAMF7-expressing NK cells. In addition to conventional antibodies, NK cell-targeted bispecific (BiKEs) and trispecific (TriKEs) killer engagers have also been developed. These proteins elicit potent effector functions by binding target ligands (e.g., CD19, CD22, CD30, CD133, HLA class II, EGFR) on one arm and NK receptors on the other. An additional innovative approach to direct NK cell activity is genetic reprogramming with chimeric antigen receptors (CAR). To date, primary NK cells and the NK92 cell line have been engineered with CAR specific for antigens expressed on multiple tumors. Encouraging preclinical results warrant further development of this approach. This Research Topic welcomes contributions addressing mechanisms of NK-mediated activation in response to disease as well as past and contemporary strategies to enhance NK mediated reactivity through control of the interactions between NK receptors and their ligands.

Breaking the cycle: Attacking the malaria parasite in the liver

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Book Series: Frontiers Research Topics ISSN: 16648714 ISBN: 9782889196951 Year: Pages: 173 DOI: 10.3389/978-2-88919-695-1 Language: English
Publisher: Frontiers Media SA
Subject: Allergy and Immunology --- Medicine (General) --- Microbiology --- Science (General)
Added to DOAB on : 2016-04-07 11:22:02
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Despite significant progress in the global fight against malaria, this parasitic infection is still responsible for nearly 300 million clinical cases and more than half a million deaths each year, predominantly in African children less than 5 years of age. The infection starts when mosquitoes transmit small numbers of parasites into the skin. From here, the parasites travel with the bloodstream to the liver where they undergo an initial round of replication and maturation to the next developmental stage that infects red blood cells. A vaccine capable of blocking the clinically silent liver phase of the Plasmodium life cycle would prevent the subsequent symptomatic phase of this tropical disease, including its frequently fatal manifestations such as severe anemia, acute lung injury, and cerebral malaria. Parasitologists, immunologists, and vaccinologists have come to appreciate the complexity of the adaptive immune response against the liver stages of this deadly parasite. Lymphocytes play a central role in the elimination of Plasmodium infected hepatocytes, both in humans and animal models, but our understanding of the exact cellular interactions and molecular effector mechanisms that lead to parasite killing within the complex hepatic microenvironment of an immune host is still rudimentary. Nevertheless, recent collaborative efforts have led to promising vaccine approaches based on liver stages that have conferred sterile immunity in humans – the University of Oxford's Ad prime / MVA boost vaccine, the Naval Medical Research Center’s DNA prime / Ad boost vaccine, Sanaria Inc.'s radiation-attenuated whole sporozoite vaccine, and Radboud University Medical Centre’s and Sanaria's derived chemoprophylaxis with sporozoites vaccines. The aim of this Research Topic is to bring together researchers with expertise in malariology, immunology, hepatology, antigen discovery and vaccine development to provide a better understanding of the basic biology of Plasmodium in the liver and the host’s innate and adaptive immune responses. Understanding the conditions required to generate complete protection in a vaccinated individual will bring us closer to our ultimate goal, namely to develop a safe, scalable, and affordable malaria vaccine capable of inducing sustained high-level protective immunity in the large proportion of the world’s population constantly at risk of malaria.

Cross Talk between Lymph Node Lymphatic Endothelial Cells and T Cells in Inflammation and Cancer

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Book Series: Frontiers Research Topics ISSN: 16648714 ISBN: 9782889453511 Year: Pages: 100 DOI: 10.3389/978-2-88945-351-1 Language: English
Publisher: Frontiers Media SA
Subject: Medicine (General) --- Allergy and Immunology
Added to DOAB on : 2018-02-27 16:16:45
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Lymphocytes constantly survey the lymph nodes in search for potential infection by a pathogen. They enter the afferent lymphatic vessel that serves as a conduit to transport the motile lymphocytes to the draining lymph node. Lymphatic vessels (LVs) are present in most vascularized tissues. They are traditionally regarded as passive conduits for soluble antigens and leukocytes. Afferent LVs begin as blind ended capillaries, which give rise to collecting vessels that merge and connect with draining lymph nodes (dLNs). Initial lymphatic capillaries are composed of Lymphatic Endothelial Cells (LECs) connected by discontinuous cell junctions, which join to form larger collecting lymphatic vessels, and ultimately feed into the LN subcapsular sinus. Within the LN, LECs are localized to the subcapsular, cortical, and medullary sinuses, where they interact with incoming and exiting leukocytes. LECs, and in general LN stromal cells, have emerged in the recent years as active players in the immune response. In support to this,studies have shown that the immune response generated during inflammation and under pathologic conditions is accompanied by modeling of the LVs and generation of new lymphatics, a process known as lymphangiogenesis. These facts strongly suggest that LECs and stromal LN cells in general, are not inert players but rather are part of the immune response by organizing immune cells movement, exchanging information and supplying survival factors. The purpose of this research topic is to review the role of the LECs during immune homeostasis and cancer. Considering the critical role of lymphangiogenesis in many pathologies like chronic and acute inflammation, autoimmunity, wound healing, graft rejection, and tumor metastasis, it is important to understand the molecular mechanisms that govern the cross talks between the LECs and immune cells during homeostasis and inflammation.

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