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Pathogenesis of Anemia in Canine Babesiosis: Possible Contribution of Pro-Inflammatory Cytokines and Chemokines-A Review. Pathogens 2023; 12:pathogens12020166. [PMID: 36839438 PMCID: PMC9962459 DOI: 10.3390/pathogens12020166] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2022] [Revised: 01/15/2023] [Accepted: 01/18/2023] [Indexed: 01/22/2023] Open
Abstract
Canine babesiosis is a tick-borne protozoan disease caused by intraerythrocytic parasites of the genus Babesia. The infection may lead to anemia in infected dogs. However, anemia is not directly caused by the pathogen. The parasite's developmental stages only have a marginal role in contributing to a decreased red blood cell (RBC) count. The main cause of anemia in affected dogs is the immune response to the infection. This response includes antibody production, erythrophagocytosis, oxidative damage of RBCs, complement activation, and antibody-dependent cellular cytotoxicity. Moreover, both infected and uninfected erythrocytes are retained in the spleen and sequestered in micro-vessels. All these actions are driven by pro-inflammatory cytokines and chemokines, especially IFN-γ, TNF-α, IL-6, and IL-8. Additionally, imbalance between the actions of pro- and anti-inflammatory cytokines plays a role in patho-mechanisms leading to anemia in canine babesiosis. This article is a review of the studies on the pathogenesis of anemia in canine babesiosis and related diseases, such as bovine or murine babesiosis and human or murine malaria, and the role of pro-inflammatory cytokines and chemokines in the mechanisms leading to anemia in infected dogs.
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2
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Role of Heat Shock Proteins in Immune Modulation in Malaria. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2021; 1340:169-186. [PMID: 34569025 DOI: 10.1007/978-3-030-78397-6_7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
Malaria is one of the major parasitic killer diseases worldwide. Severe cases of malaria are mostly in children under the age of 5 years due to their naïve immune system and in pregnant women with weakened immune responses. Inflammatory immune responses against the parasite involve complement activation as well as the antibody and effector cell-mediated immune system. However, after an infection with Plasmodium falciparum (P. falciparum), the most dangerous malaria species, the host-derived immunity is often insufficient to completely inhibit the infection cycles of the parasite in red blood cells for yet unknown reasons. In the present chapter we aim to elucidate the role of the host's and the parasite's heat shock proteins (HSPs) in the development of a novel anti-malaria therapeutic approach.
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3
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Bucşan AN, Williamson KC. Setting the stage: The initial immune response to blood-stage parasites. Virulence 2020; 11:88-103. [PMID: 31900030 PMCID: PMC6961725 DOI: 10.1080/21505594.2019.1708053] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2019] [Revised: 12/05/2019] [Accepted: 12/09/2019] [Indexed: 01/22/2023] Open
Abstract
Individuals growing up in malaria endemic areas gradually develop protection against clinical malaria and passive transfer experiments in humans have demonstrated that this protection is mediated in part by protective antibodies. However, neither the target antigens, specific effector mechanisms, nor the role of continual parasite exposure have been elucidated, which complicates vaccine development. Progress has been made in defining the innate signaling pathways activated by parasite components, including DNA, RNA, hemozoin, and phospholipids, which initiate the immune response and will be the focus of this review. The challenge that remains within the field is to understand the role of these early responses in the development of protective adaptive responses that clear iRBC and block merozoite invasion so that optimal vaccines and therapeutics may be produced.
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Affiliation(s)
- Allison N. Bucşan
- Department of Microbiology and Immunology, Uniformed Services University of the Health Sciences, Bethesda, MD, USA
| | - Kim C. Williamson
- Department of Microbiology and Immunology, Uniformed Services University of the Health Sciences, Bethesda, MD, USA
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4
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PD-1 Expression on NK Cells in Malaria-Exposed Individuals Is Associated with Diminished Natural Cytotoxicity and Enhanced Antibody-Dependent Cellular Cytotoxicity. Infect Immun 2020; 88:IAI.00711-19. [PMID: 31907195 DOI: 10.1128/iai.00711-19] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2019] [Accepted: 12/16/2019] [Indexed: 12/15/2022] Open
Abstract
Natural killer (NK) cells are key effector cells of innate resistance capable of destroying tumors and virus-infected cells through cytotoxicity and rapid cytokine production. The control of NK cell responses is complex and only partially understood. PD-1 is an inhibitory receptor that regulates T cell function, but a role for PD-1 in regulating NK cell function is only beginning to emerge. Here, we investigated PD-1 expression on NK cells in children and adults in Mali in a longitudinal analysis before, during, and after infection with Plasmodium falciparum malaria. We found that NK cells transiently upregulate PD-1 expression and interleukin-6 (IL-6) production in some individuals during acute febrile malaria. Furthermore, the percentage of PD-1 expressing NK cells increases with age and cumulative malaria exposure. Consistent with this, NK cells of malaria-naive adults upregulated PD-1 following P. falciparum stimulation in vitro Additionally, functional in vitro studies revealed that PD-1 expression on NK cells is associated with diminished natural cytotoxicity but enhanced antibody-dependent cellular cytotoxicity (ADCC). These data indicate that PD-1+ NK cells expand in the context of chronic immune activation and suggest that PD-1 may contribute to skewing NK cells toward enhanced ADCC during infections such as malaria.
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5
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Walk J, Sauerwein RW. Activatory Receptor NKp30 Predicts NK Cell Activation During Controlled Human Malaria Infection. Front Immunol 2019; 10:2864. [PMID: 31921133 PMCID: PMC6916516 DOI: 10.3389/fimmu.2019.02864] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2019] [Accepted: 11/21/2019] [Indexed: 12/12/2022] Open
Abstract
Natural killer (NK) cells are known to be activated during malaria infection, exhibiting both cytokine production and cytotoxic functions. However, NK cells are heterogeneous in their expression of surface activatory and inhibitory receptors which may influence their response to malaria parasites. Here, we studied the surface marker profile and activation dynamics of NK cells during a Controlled Human Malaria Infection in 12 healthy volunteers. Although there was significant inter-patient variability in timing and magnitude of NK cell activation, we found a consistent and strong increase in expression of the activatory receptor NKp30. Moreover, high baseline NKp30 expression was associated with NK cell activation at lower parasite densities. Our data suggest that NKp30 expression may influence the NK cell response to P. falciparum, explaining inter-patient heterogeneity and suggesting a functional role for this receptor in malaria.
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Affiliation(s)
- Jona Walk
- Department of Medical Microbiology and Radboud Center for Infectious Diseases, Radboud University Medical Center, Nijmegen, Netherlands
| | - Robert W Sauerwein
- Department of Medical Microbiology and Radboud Center for Infectious Diseases, Radboud University Medical Center, Nijmegen, Netherlands
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6
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Burrack KS, Hart GT, Hamilton SE. Contributions of natural killer cells to the immune response against Plasmodium. Malar J 2019; 18:321. [PMID: 31533835 PMCID: PMC6751859 DOI: 10.1186/s12936-019-2953-1] [Citation(s) in RCA: 35] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2019] [Accepted: 09/07/2019] [Indexed: 01/08/2023] Open
Abstract
Natural killer (NK) cells are important innate effector cells that are well described in their ability to kill virally-infected cells and tumors. However, there is increasing appreciation for the role of NK cells in the control of other pathogens, including intracellular parasites such as Plasmodium, the cause of malaria. NK cells may be beneficial during the early phase of Plasmodium infection—prior to the activation and expansion of antigen-specific T cells—through cooperation with myeloid cells to produce inflammatory cytokines like IFNγ. Recent work has defined how Plasmodium can activate NK cells to respond with natural cytotoxicity, and inhibit the growth of parasites via antibody-dependent cellular cytotoxicity mechanisms (ADCC). A specialized subset of adaptive NK cells that are negative for the Fc receptor γ chain have enhanced ADCC function and correlate with protection from malaria. Additionally, production of the regulatory cytokine IL-10 by NK cells prevents overt pathology and death during experimental cerebral malaria. Now that conditional NK cell mouse models have been developed, previous studies need to be reevaluated in the context of what is now known about other immune populations with similarity to NK cells (i.e., NKT cells and type I innate lymphoid cells). This brief review summarizes recent findings which support the potentially beneficial roles of NK cells during Plasmodium infection in mice and humans. Also highlighted are how the actions of NK cells can be explored using new experimental strategies, and the potential to harness NK cell function in vaccination regimens.
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Affiliation(s)
- Kristina S Burrack
- Department of Medicine, Hennepin Healthcare Research Institute, Minneapolis, MN, 55415, USA
| | - Geoffrey T Hart
- Center for Immunology, Department of Medicine, Division of Infectious Disease and International Medicine, University of Minnesota, Minneapolis, MN, 55455, USA
| | - Sara E Hamilton
- Center for Immunology, Department of Laboratory Medicine and Pathology, University of Minnesota, Minneapolis, MN, 55414, USA.
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7
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Ivanova DL, Denton SL, Fettel KD, Sondgeroth KS, Munoz Gutierrez J, Bangoura B, Dunay IR, Gigley JP. Innate Lymphoid Cells in Protection, Pathology, and Adaptive Immunity During Apicomplexan Infection. Front Immunol 2019; 10:196. [PMID: 30873151 PMCID: PMC6403415 DOI: 10.3389/fimmu.2019.00196] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2018] [Accepted: 01/23/2019] [Indexed: 12/23/2022] Open
Abstract
Apicomplexans are a diverse and complex group of protozoan pathogens including Toxoplasma gondii, Plasmodium spp., Cryptosporidium spp., Eimeria spp., and Babesia spp. They infect a wide variety of hosts and are a major health threat to humans and other animals. Innate immunity provides early control and also regulates the development of adaptive immune responses important for controlling these pathogens. Innate immune responses also contribute to immunopathology associated with these infections. Natural killer (NK) cells have been for a long time known to be potent first line effector cells in helping control protozoan infection. They provide control by producing IL-12 dependent IFNγ and killing infected cells and parasites via their cytotoxic response. Results from more recent studies indicate that NK cells could provide additional effector functions such as IL-10 and IL-17 and might have diverse roles in immunity to these pathogens. These early studies based their conclusions on the identification of NK cells to be CD3–, CD49b+, NK1.1+, and/or NKp46+ and the common accepted paradigm at that time that NK cells were one of the only lymphoid derived innate immune cells present. New discoveries have lead to major advances in understanding that NK cells are only one of several populations of innate immune cells of lymphoid origin. Common lymphoid progenitor derived innate immune cells are now known as innate lymphoid cells (ILC) and comprise three different groups, group 1, group 2, and group 3 ILC. They are a functionally heterogeneous and plastic cell population and are important effector cells in disease and tissue homeostasis. Very little is known about each of these different types of ILCs in parasitic infection. Therefore, we will review what is known about NK cells in innate immune responses during different protozoan infections. We will discuss what immune responses attributed to NK cells might be reconsidered as ILC1, 2, or 3 population responses. We will then discuss how different ILCs may impact immunopathology and adaptive immune responses to these parasites.
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Affiliation(s)
- Daria L Ivanova
- Molecular Biology, University of Wyoming, Laramie, WY, United States
| | - Stephen L Denton
- Molecular Biology, University of Wyoming, Laramie, WY, United States
| | - Kevin D Fettel
- Molecular Biology, University of Wyoming, Laramie, WY, United States
| | | | - Juan Munoz Gutierrez
- Microbiology, Immunology and Pathology, College of Veterinary Medicine and Biomedical Sciences, Colorado State University, Fort Collins, CO, United States
| | - Berit Bangoura
- Veterinary Sciences, University of Wyoming, Laramie, WY, United States
| | - Ildiko R Dunay
- Institute of Inflammation and Neurodegeneration, Otto-von-Guericke Universität Magdeburg, Magdeburg, Germany
| | - Jason P Gigley
- Molecular Biology, University of Wyoming, Laramie, WY, United States
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8
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Ng SS, Engwerda CR. Innate Lymphocytes and Malaria - Players or Spectators? Trends Parasitol 2018; 35:154-162. [PMID: 30579700 DOI: 10.1016/j.pt.2018.11.012] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2018] [Revised: 11/29/2018] [Accepted: 11/29/2018] [Indexed: 12/19/2022]
Abstract
Malaria remains an important global disease. Despite significant advances over the past decade in reducing disease morbidity and mortality, new measures are needed if malaria is to be eliminated. Significant advances in our understanding about host immune responses during malaria have been made, opening up opportunities to generate long-lasting antiparasitic immunity through vaccination or immune therapy. However, there is still much debate over which immune cell populations contribute to immunity to malaria, including innate lymphocytes that comprise recently identified innate lymphoid cells (ILCs) and better known innate-like T cell subsets. Here, we review research on these immune cell subsets and discuss whether they have any important roles in immunity to malaria or if they are redundant.
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Affiliation(s)
- Susanna S Ng
- Immunology and Infection Laboratory, QIMR Berghofer Medical Research Institute, QLD, Australia; School of Environment and Science, Griffith University, QLD, Australia
| | - Christian R Engwerda
- Immunology and Infection Laboratory, QIMR Berghofer Medical Research Institute, QLD, Australia.
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9
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Ye W, Chew M, Hou J, Lai F, Leopold SJ, Loo HL, Ghose A, Dutta AK, Chen Q, Ooi EE, White NJ, Dondorp AM, Preiser P, Chen J. Microvesicles from malaria-infected red blood cells activate natural killer cells via MDA5 pathway. PLoS Pathog 2018; 14:e1007298. [PMID: 30286211 PMCID: PMC6171940 DOI: 10.1371/journal.ppat.1007298] [Citation(s) in RCA: 45] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2018] [Accepted: 08/26/2018] [Indexed: 11/23/2022] Open
Abstract
Natural killer (NK) cells provide the first line of defense against malaria parasite infection. However, the molecular mechanisms through which NK cells are activated by parasites are largely unknown, so is the molecular basis underlying the variation in NK cell responses to malaria infection in the human population. Here, we compared transcriptional profiles of responding and non-responding NK cells following exposure to Plasmodium-infected red blood cells (iRBCs) and identified MDA5, a RIG-I-like receptor involved in sensing cytosolic RNAs, to be differentially expressed. Knockout of MDA5 in responding human NK cells by CRISPR/cas9 abolished NK cell activation, IFN-γ secretion, lysis of iRBCs. Similarly, inhibition of TBK1/IKKε, an effector molecule downstream of MDA5, also inhibited activation of responding NK cells. Conversely, activation of MDA5 by liposome-packaged poly I:C restored non-responding NK cells to lyse iRBCs. We further show that microvesicles containing large parasite RNAs from iRBCs activated NK cells by fusing with NK cells. These findings suggest that NK cells are activated through the MDA5 pathway by parasite RNAs that are delivered to the cytoplasm of NK cells by microvesicles from iRBCs. The difference in MDA5 expression between responding and non-responding NK cells following exposure to iRBCs likely contributes to the variation in NK cell responses to malaria infection in the human population. Malaria is an important parasitic disease with a major public health concern. Malaria pathogenesis involves a complex interplay between parasitic and host factors. A better understanding of early host response and the determinants of immunity are essential to developing innovative therapeutic approaches. Natural killer (NK) cells are important immune cells in protection against malaria infection but show significant differences in their responses in the human population. Here we analyze the differences between human NK cells that respond to and don’t respond to malaria infection. We found that human NK cells that respond to malaria-infected red blood cells (iRBC) have higher levels of a pathogen recognition receptor, MDA5. This receptor is activated by small vesicles released from iRBC. By activating MDA5 with a small molecule agonist, we can improve non-responder NK cells to clear iRBC. Our study provides new insights into the mechanism by which NK cells control malaria infection and possible NK cell-based intervention of malaria infection in human.
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Affiliation(s)
- Weijian Ye
- School of Biological Sciences, Nanyang Technological University, Singapore.,Singapore-MIT Alliance for Research and Technology, Infectious Disease Interdisciplinary Research Group, Singapore
| | - Marvin Chew
- School of Biological Sciences, Nanyang Technological University, Singapore.,Singapore-MIT Alliance for Research and Technology, Infectious Disease Interdisciplinary Research Group, Singapore
| | - Jue Hou
- Singapore-MIT Alliance for Research and Technology, Infectious Disease Interdisciplinary Research Group, Singapore
| | - Fritz Lai
- Humanized Mouse Unit, Institute of Molecular and Cell Biology, Agency of Science, Technology and Research, Singapore
| | - Stije J Leopold
- Mahidol Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand.,Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of Oxford, Oxford, United Kingdom
| | - Hooi Linn Loo
- Singapore-MIT Alliance for Research and Technology, Infectious Disease Interdisciplinary Research Group, Singapore
| | - Aniruddha Ghose
- Department of Internal Medicine, Chittagong Medical College Hospital, Chittagong, Bangladesh
| | - Ashok K Dutta
- Department of Internal Medicine, Chittagong Medical College Hospital, Chittagong, Bangladesh
| | - Qingfeng Chen
- Humanized Mouse Unit, Institute of Molecular and Cell Biology, Agency of Science, Technology and Research, Singapore
| | - Eng Eong Ooi
- Singapore-MIT Alliance for Research and Technology, Infectious Disease Interdisciplinary Research Group, Singapore.,Duke-National University of Singapore Medical School, Singapore
| | - Nicholas J White
- Mahidol Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand.,Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of Oxford, Oxford, United Kingdom
| | - Arjen M Dondorp
- Mahidol Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand.,Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of Oxford, Oxford, United Kingdom
| | - Peter Preiser
- School of Biological Sciences, Nanyang Technological University, Singapore.,Singapore-MIT Alliance for Research and Technology, Infectious Disease Interdisciplinary Research Group, Singapore
| | - Jianzhu Chen
- Singapore-MIT Alliance for Research and Technology, Infectious Disease Interdisciplinary Research Group, Singapore.,Koch Institute for Integrative Cancer Research and Department of Biology, Massachusetts Institute of Technology, Cambridge, MA, United States of America
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10
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Arora G, Hart GT, Manzella-Lapeira J, Doritchamou JY, Narum DL, Thomas LM, Brzostowski J, Rajagopalan S, Doumbo OK, Traore B, Miller LH, Pierce SK, Duffy PE, Crompton PD, Desai SA, Long EO. NK cells inhibit Plasmodium falciparum growth in red blood cells via antibody-dependent cellular cytotoxicity. eLife 2018; 7:36806. [PMID: 29943728 PMCID: PMC6019063 DOI: 10.7554/elife.36806] [Citation(s) in RCA: 74] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2018] [Accepted: 05/31/2018] [Indexed: 12/22/2022] Open
Abstract
Antibodies acquired naturally through repeated exposure to Plasmodium falciparum are essential in the control of blood-stage malaria. Antibody-dependent functions may include neutralization of parasite–host interactions, complement activation, and activation of Fc receptor functions. A role of antibody-dependent cellular cytotoxicity (ADCC) by natural killer (NK) cells in protection from malaria has not been established. Here we show that IgG isolated from adults living in a malaria-endemic region activated ADCC by primary human NK cells, which lysed infected red blood cells (RBCs) and inhibited parasite growth in an in vitro assay for ADCC-dependent growth inhibition. RBC lysis by NK cells was highly selective for infected RBCs in a mixed culture with uninfected RBCs. Human antibodies to P. falciparum antigens PfEMP1 and RIFIN were sufficient to promote NK-dependent growth inhibition. As these results implicate acquired immunity through NK-mediated ADCC, antibody-based vaccines that target bloodstream parasites should consider this new mechanism of action. Malaria is a deadly disease caused by a parasite transmitted by mosquitoes. The parasite infects red blood cells, causing fever with flu-like symptoms. In some people, particularly pregnant women and children, the disease may be very serious and even lead to death. An effective malaria vaccine is urgently needed because malaria parasites are developing resistance to current drugs. People living in areas where malaria is common develop specific proteins called antibodies that protect them from malaria. Learning more about how the antibodies achieve this, could help to develop better vaccines. Scientists already know some antibodies bind to the malaria parasites and prevent them from entering red blood cells. Some vaccines have been based on these antibodies. Other antibodies bind to infected cells flagging them for destruction by cells of the immune system. Immune cells called natural killer cells can eliminate viruses or cancer cells this way, but it was not clear if they could also eliminate malaria parasite-infected red blood cells. Now, Arora et al. show that natural killer cells can selectively destroy malaria-infected red blood cells flagged with antibodies from people who live in areas where malaria is common. In laboratory experiments, natural killer cells from US volunteers, who were never exposed to malaria, did not kill normal or malaria-infected red blood cells. Adding antibodies collected from malaria-resistant volunteers from Africa allowed these natural killer cells from unexposed people to selectively seek out and destroy malaria-infected cells and leave uninfected red blood cells intact. Arora et al. also found that the antibodies from the malaria-resistant volunteers bound to parasite proteins on the surface of infected blood cells. The experiments suggest that vaccines designed to stimulate the production of antibodies to malaria proteins that are displayed on infected red blood cells, could destroy the parasite in infected people and help prevent disease and save lives.
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Affiliation(s)
- Gunjan Arora
- Laboratory of Immunogenetics, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Rockville, United States
| | - Geoffrey T Hart
- Laboratory of Immunogenetics, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Rockville, United States.,Department of Medicine, University of Minnesota, Minneapolis, United States
| | - Javier Manzella-Lapeira
- Laboratory of Immunogenetics, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Rockville, United States
| | - Justin Ya Doritchamou
- Laboratory of Malaria Immunology and Vaccinology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Rockville, United States
| | - David L Narum
- Laboratory of Malaria Immunology and Vaccinology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Rockville, United States
| | - L Michael Thomas
- Laboratory of Immunogenetics, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Rockville, United States
| | - Joseph Brzostowski
- Laboratory of Immunogenetics, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Rockville, United States
| | - Sumati Rajagopalan
- Laboratory of Immunogenetics, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Rockville, United States
| | - Ogobara K Doumbo
- Malaria Research and Training Centre, Department of Epidemiology of Parasitic Diseases, International Center of Excellence in Research, University of Sciences, Techniques and Technologies of Bamako, Bamako, Mali
| | - Boubacar Traore
- Malaria Research and Training Centre, Department of Epidemiology of Parasitic Diseases, International Center of Excellence in Research, University of Sciences, Techniques and Technologies of Bamako, Bamako, Mali
| | - Louis H Miller
- Laboratory of Malaria and Vector Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Rockville, United States
| | - Susan K Pierce
- Laboratory of Immunogenetics, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Rockville, United States
| | - Patrick E Duffy
- Laboratory of Malaria Immunology and Vaccinology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Rockville, United States
| | - Peter D Crompton
- Laboratory of Immunogenetics, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Rockville, United States
| | - Sanjay A Desai
- Laboratory of Malaria and Vector Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Rockville, United States
| | - Eric O Long
- Laboratory of Immunogenetics, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Rockville, United States
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11
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Kijogi C, Kimura D, Bao LQ, Nakamura R, Chadeka EA, Cheruiyot NB, Bahati F, Yahata K, Kaneko O, Njenga SM, Ichinose Y, Hamano S, Yui K. Modulation of immune responses by Plasmodium falciparum infection in asymptomatic children living in the endemic region of Mbita, western Kenya. Parasitol Int 2018; 67:284-293. [PMID: 29353010 DOI: 10.1016/j.parint.2018.01.001] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2017] [Revised: 01/06/2018] [Accepted: 01/14/2018] [Indexed: 11/24/2022]
Abstract
Individuals living in malaria endemic areas become clinically immune after multiple re-infections over time and remain infected without apparent symptoms. However, it is unclear why a long period is required to gain clinical immunity to malaria, and how such immunity is maintained. Although malaria infection is reported to induce inhibition of immune responses, studies on asymptomatic individuals living in endemic regions of malaria are relatively scarce. We conducted a cross-sectional study of immune responses in asymptomatic school children aged 4-16years living in an area where Plasmodium falciparum and Schistosoma mansoni infections are co-endemic in Kenya. Peripheral blood mononuclear cells were subjected to flow cytometric analysis and cultured to determine proliferative responses and cytokine production. The proportions of cellular subsets in children positive for P. falciparum infection at the level of microscopy were comparable to the negative children, except for a reduction in central memory-phenotype CD8+ T cells and natural killer cells. In functional studies, the production of cytokines by peripheral blood mononuclear cells in response to P. falciparum crude antigens exhibited strong heterogeneity among children. In addition, production of IL-2 in response to anti-CD3 and anti-CD28 monoclonal antibodies was significantly reduced in P. falciparum-positive children as compared to -negative children, suggesting a state of unresponsiveness. These data suggest that the quality of T cell immune responses is heterogeneous among asymptomatic children living in the endemic region of P. falciparum, and that the responses are generally suppressed by active infection with Plasmodium parasites.
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Affiliation(s)
- Caroline Kijogi
- Division of Immunology, Department of Molecular Microbiology and Immunology, Graduate School of Biomedical Sciences, Nagasaki University, 1-12-4 Sakamoto, Nagasaki 852-8523, Japan; Program for Nurturing Global Leaders in Tropical and Emerging Infectious Diseases, Graduate School of Biomedical Sciences, Nagasaki University, 1-12-4 Sakamoto, Nagasaki 852-8523, Japan
| | - Daisuke Kimura
- Division of Immunology, Department of Molecular Microbiology and Immunology, Graduate School of Biomedical Sciences, Nagasaki University, 1-12-4 Sakamoto, Nagasaki 852-8523, Japan
| | - Lam Quoc Bao
- Department of Parasitology, Institute of Tropical Medicine (NEKKEN), Nagasaki University, 1-12-4 Sakamoto, Nagasaki 852-8523, Japan; The Joint Usage/Research Center on Tropical Disease, Institute of Tropical Medicine (NEKKEN), Nagasaki University
| | - Risa Nakamura
- Program for Nurturing Global Leaders in Tropical and Emerging Infectious Diseases, Graduate School of Biomedical Sciences, Nagasaki University, 1-12-4 Sakamoto, Nagasaki 852-8523, Japan; Department of Parasitology, Institute of Tropical Medicine (NEKKEN), Nagasaki University, 1-12-4 Sakamoto, Nagasaki 852-8523, Japan; The Joint Usage/Research Center on Tropical Disease, Institute of Tropical Medicine (NEKKEN), Nagasaki University
| | - Evans Asena Chadeka
- Program for Nurturing Global Leaders in Tropical and Emerging Infectious Diseases, Graduate School of Biomedical Sciences, Nagasaki University, 1-12-4 Sakamoto, Nagasaki 852-8523, Japan; Department of Parasitology, Institute of Tropical Medicine (NEKKEN), Nagasaki University, 1-12-4 Sakamoto, Nagasaki 852-8523, Japan; The Joint Usage/Research Center on Tropical Disease, Institute of Tropical Medicine (NEKKEN), Nagasaki University; Nagasaki University Kenya Research Station, NUITM-KEMRI Project, Nairobi, Kenya
| | - Ngetich Benard Cheruiyot
- The Joint Usage/Research Center on Tropical Disease, Institute of Tropical Medicine (NEKKEN), Nagasaki University; Nagasaki University Kenya Research Station, NUITM-KEMRI Project, Nairobi, Kenya
| | - Felix Bahati
- The Joint Usage/Research Center on Tropical Disease, Institute of Tropical Medicine (NEKKEN), Nagasaki University; Nagasaki University Kenya Research Station, NUITM-KEMRI Project, Nairobi, Kenya
| | - Kazuhide Yahata
- The Joint Usage/Research Center on Tropical Disease, Institute of Tropical Medicine (NEKKEN), Nagasaki University; Department of Protozoology, Institute of Tropical Medicine (NEKKEN), Nagasaki University, 1-12-4 Sakamoto, Nagasaki 852-8523, Japan
| | - Osamu Kaneko
- Program for Nurturing Global Leaders in Tropical and Emerging Infectious Diseases, Graduate School of Biomedical Sciences, Nagasaki University, 1-12-4 Sakamoto, Nagasaki 852-8523, Japan; The Joint Usage/Research Center on Tropical Disease, Institute of Tropical Medicine (NEKKEN), Nagasaki University; Department of Protozoology, Institute of Tropical Medicine (NEKKEN), Nagasaki University, 1-12-4 Sakamoto, Nagasaki 852-8523, Japan
| | - Sammy M Njenga
- Eastern and Southern Africa Centre of International Parasite Control (ESACIPAC), Kenya Medical Research Institute (KEMRI), Nairobi, Kenya
| | - Yoshio Ichinose
- Program for Nurturing Global Leaders in Tropical and Emerging Infectious Diseases, Graduate School of Biomedical Sciences, Nagasaki University, 1-12-4 Sakamoto, Nagasaki 852-8523, Japan; The Joint Usage/Research Center on Tropical Disease, Institute of Tropical Medicine (NEKKEN), Nagasaki University; Nagasaki University Kenya Research Station, NUITM-KEMRI Project, Nairobi, Kenya
| | - Shinjiro Hamano
- Program for Nurturing Global Leaders in Tropical and Emerging Infectious Diseases, Graduate School of Biomedical Sciences, Nagasaki University, 1-12-4 Sakamoto, Nagasaki 852-8523, Japan; Department of Parasitology, Institute of Tropical Medicine (NEKKEN), Nagasaki University, 1-12-4 Sakamoto, Nagasaki 852-8523, Japan; The Joint Usage/Research Center on Tropical Disease, Institute of Tropical Medicine (NEKKEN), Nagasaki University; Nagasaki University Kenya Research Station, NUITM-KEMRI Project, Nairobi, Kenya
| | - Katsuyuki Yui
- Division of Immunology, Department of Molecular Microbiology and Immunology, Graduate School of Biomedical Sciences, Nagasaki University, 1-12-4 Sakamoto, Nagasaki 852-8523, Japan; Program for Nurturing Global Leaders in Tropical and Emerging Infectious Diseases, Graduate School of Biomedical Sciences, Nagasaki University, 1-12-4 Sakamoto, Nagasaki 852-8523, Japan.
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12
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Papazahariadou M, Athanasiadis GI, Papadopoulos E, Symeonidou I, Hatzistilianou M, Castellani ML, Bhattacharya K, Shanmugham LN, Conti P, Frydas S. Involvement of NK Cells against Tumors and Parasites. Int J Biol Markers 2018; 22:144-53. [PMID: 17549670 DOI: 10.1177/172460080702200208] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Host resistance against pathogens depends on a complex interplay of innate and adaptive immune mechanisms. Acting as an early line of defence, the immune system includes activation of neutrophils, tissue macrophages, monocytes, dendritic cells, eosinophils and natural killer (NK) cells. NK cells are lymphoid cells that can be activated without previous stimulation and are therefore like macrophages in the first line of defence against tumor cells and a diverse range of pathogens. NK cells mediate significant activity and produce high levels of proinflammatory cytokines in response to infection. Their cytotoxicity production is induced principally by monocyte-, macrophage- and dendritic cell-derived cytokines, but their activation is also believed to be cytokine-mediated. Recognition of infection by NK cells is accomplished by numerous activating and inhibitory receptors on the NK cells’ surface that selectively trigger the cytolytic activity in a major histocompability complex-independent manner. NK cells have trypanocidal activity of fibroblast cells and mediate direct destruction of extracellular epimastigote and trypomastigote forms of T. cruzi and T. lewisi in vitro; moreover, they kill plasmodia-infected erythrocytes directly through cell-cell interaction. This review provides a more detailed analysis of how NK cells recognize and respond to parasites and how they mediate cytotoxicity against tumor cells. Also the unique role of NK cells in innate immunity to infection and the relationship between parasites and carcinogenesis are discussed.
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Affiliation(s)
- M Papazahariadou
- Laboratory of Parasitology, Veterinary Faculty, Aristotele University, Thessaloniki, Greece
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13
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Beyond genome-wide scan: Association of a cis-regulatory NCR3 variant with mild malaria in a population living in the Republic of Congo. PLoS One 2017; 12:e0187818. [PMID: 29121672 PMCID: PMC5679660 DOI: 10.1371/journal.pone.0187818] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2017] [Accepted: 10/26/2017] [Indexed: 12/15/2022] Open
Abstract
Linkage studies have revealed a linkage of mild malaria to chromosome 6p21 that contains the NCR3 gene encoding a natural killer cell receptor, whereas NCR3-412G>C (rs2736191) located in its promoter region was found to be associated with malaria in Burkina Faso. Here we confirmed the association of rs2736191 with mild malaria in a Congolese cohort and investigated its potential cis-regulatory effect. Luciferase assay results indicated that rs2736191-G allele had a significantly increased promoter activity compared to rs2736191-C allele. Furthermore, EMSAs demonstrated an altered binding of two nuclear protein complexes to the rs2736191-C allele in comparison to rs2736191-G allele. Finally, after in silico identification of transcription factor candidates, pull-down western blot experiments confirmed that both STAT4 and RUNX3 bind the region encompassing rs2736191 with a higher affinity for the G allele. To our knowledge, this is the first report that explored the functional role of rs2736191. These results support the hypothesis that genetic variation within natural killer cell receptors alters malaria resistance in humans.
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14
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Marquet S. Overview of human genetic susceptibility to malaria: From parasitemia control to severe disease. INFECTION GENETICS AND EVOLUTION 2017; 66:399-409. [PMID: 28579526 DOI: 10.1016/j.meegid.2017.06.001] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/10/2017] [Revised: 05/31/2017] [Accepted: 06/01/2017] [Indexed: 10/19/2022]
Abstract
Malaria is a life-threatening blood disease caused by the protozoan Plasmodium. Infection may lead to several different patterns of symptoms in the host: asymptomatic state, uncomplicated disease or severe disease. Severe malaria occurs mostly in young children and is a major cause of death. Disease is thought to result from the sequestration of parasites in the small blood vessels of the brain and the deregulation of key immune system elements. The cellular and molecular regulatory mechanisms underlying the pathogenesis of disease are however not fully understood. What is known it is that the genetic determinants of the host play an important role in the severity of the disease and the outcome of infection. Here we review the most convincing results obtained through genetic epidemiology studies concerning the genetic control of malaria in human caused by Plasmodium falciparum infection. The identification of genes conferring susceptibility or resistance to malaria might improve diagnosis and treatment.
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Affiliation(s)
- Sandrine Marquet
- Aix-Marseille University, INSERM, GIMP, Labex ParaFrap, Marseille, France.
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15
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Acharya P, Garg M, Kumar P, Munjal A, Raja KD. Host-Parasite Interactions in Human Malaria: Clinical Implications of Basic Research. Front Microbiol 2017; 8:889. [PMID: 28572796 PMCID: PMC5435807 DOI: 10.3389/fmicb.2017.00889] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2017] [Accepted: 05/02/2017] [Indexed: 12/21/2022] Open
Abstract
The malaria parasite, Plasmodium, is one of the oldest parasites documented to infect humans and has proven particularly hard to eradicate. One of the major hurdles in designing an effective subunit vaccine against the malaria parasite is the insufficient understanding of host–parasite interactions within the human host during infections. The success of the parasite lies in its ability to evade the human immune system and recruit host responses as physiological cues to regulate its life cycle, leading to rapid acclimatization of the parasite to its immediate host environment. Hence understanding the environmental niche of the parasite is crucial in developing strategies to combat this deadly infectious disease. It has been increasingly recognized that interactions between parasite proteins and host factors are essential to establishing infection and virulence at every stage of the parasite life cycle. This review reassesses all of these interactions and discusses their clinical importance in designing therapeutic approaches such as design of novel vaccines. The interactions have been followed from the initial stages of introduction of the parasite under the human dermis until asexual and sexual blood stages which are essential for transmission of malaria. We further classify the interactions as “direct” or “indirect” depending upon their demonstrated ability to mediate direct physical interactions of the parasite with host factors or their indirect manipulation of the host immune system since both forms of interactions are known to have a crucial role during infections. We also discuss the many ways in which this understanding has been taken to the field and the success of these strategies in controlling human malaria.
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Affiliation(s)
- Pragyan Acharya
- Department of Biochemistry, All India Institute of Medical SciencesNew Delhi, India
| | - Manika Garg
- Department of Biochemistry, Jamia Hamdard UniversityNew Delhi, India
| | - Praveen Kumar
- Department of Biochemistry, All India Institute of Medical SciencesNew Delhi, India
| | - Akshay Munjal
- Department of Biochemistry, All India Institute of Medical SciencesNew Delhi, India
| | - K D Raja
- Department of Biochemistry, All India Institute of Medical SciencesNew Delhi, India
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16
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Wolf AS, Sherratt S, Riley EM. NK Cells: Uncertain Allies against Malaria. Front Immunol 2017; 8:212. [PMID: 28337195 PMCID: PMC5343013 DOI: 10.3389/fimmu.2017.00212] [Citation(s) in RCA: 50] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2017] [Accepted: 02/15/2017] [Indexed: 12/24/2022] Open
Abstract
Until recently, studies of natural killer (NK) cells in infection have focused almost entirely on their role in viral infections. However, there is an increasing awareness of the potential for NK cells to contribute to the control of a wider range of pathogens, including intracellular parasites such as Plasmodium spp. Given the high prevalence of parasitic diseases in the developing world and the devastating effects these pathogens have on large numbers of vulnerable people, investigating interactions between NK cells and parasitized host cells presents the opportunity to reveal novel immunological mechanisms with the potential to aid efforts to eradicate these diseases. The capacity of NK cells to produce inflammatory cytokines early after malaria infection, as well as a possible role in direct cytotoxic killing of malaria-infected cells, suggests a beneficial impact of NK cells in this disease. However, NK cells may also contribute to overproduction of pro-inflammatory cytokines and the consequent immunopathology. As comparatively little is known about the role of NK cells later in the course of infection, and growing evidence suggests that heterogeneity in NK cell responses to malaria may be influenced by KIR/HLA interactions, a better understanding of the mechanisms by which NK cells might directly interact with parasitized cells may reveal a new role for these cells in the course of malaria infection.
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Affiliation(s)
- Asia-Sophia Wolf
- Department of Immunology and Infection, London School of Hygiene and Tropical Medicine , London , UK
| | - Samuel Sherratt
- Department of Immunology and Infection, London School of Hygiene and Tropical Medicine , London , UK
| | - Eleanor M Riley
- Department of Immunology and Infection, London School of Hygiene and Tropical Medicine , London , UK
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17
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Ivanova DL, Fatima R, Gigley JP. Comparative Analysis of Conventional Natural Killer Cell Responses to Acute Infection with Toxoplasma gondii Strains of Different Virulence. Front Immunol 2016; 7:347. [PMID: 27721814 PMCID: PMC5033988 DOI: 10.3389/fimmu.2016.00347] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2016] [Accepted: 08/30/2016] [Indexed: 12/14/2022] Open
Abstract
Conventional natural killer (cNK) cells, members of group 1 innate lymphoid cells, are a diverse cell subpopulation based on surface receptor expression, maturation, and functional potential. cNK cells are critical for early immunity to Toxoplasma gondii via IFNγ production. Acute cNK cell responses to infection with different strains of T. gondii have not yet been characterized in detail. Here, we comprehensively performed this analysis with Type I virulent RH, Type II avirulent ME49, and fully attenuated Type I cps1-1 strains. In response to these three parasite strains, murine cNK cells produce IFNγ and become cytotoxic and polyfunctional (IFNγ+CD107a+) at the site of infection. In contrast to virulent RH and avirulent ME49 T. gondii strains, attenuated cps1-1 induced only local cNK cell responses. Infections with RH and ME49 parasites significantly decreased cNK cell frequency and numbers in spleen 5 days post infection compared with cps1-1 parasites. cNK cell subsets expressing activating receptors Ly49H, Ly49D, and NKG2D and inhibitory receptors Ly49I and CD94/NKG2A were similar when compared between the strains and at 5 days post infection. cNK cells were not proliferating (Ki67−) 5 days post infection with any of the strains. cNK cell maturation as measured by CD27, CD11b, and KLRG1 was affected after infection with different parasite strains. RH and ME49 infection significantly reduced mature cNK cell frequency and increased immature cNK cell populations compared with cps1-1 infection. Interestingly, KLRG1 was highly expressed on immature cNK cells after RH infection. After RH and ME49 infections, CD69+ cNK cells in spleen were present at higher frequency than after cps1-1 infection, which may correlate with loss of the mature cNK cell population. Cytokine multiplex analysis indicated cNK cell responses correlated with peritoneal exudate cell, spleen, and serum proinflammatory cytokine levels, including IL-12. qPCR analysis of parasite-specific B1 gene revealed that parasite burdens may affect cNK cell responses. This study demonstrates infection with RH and ME49 parasites impacts cNK cell maturation during acute T. gondii infection. Different cNK cell responses could impact early immunity and susceptibility to these strains.
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Affiliation(s)
- Daria L Ivanova
- Department of Molecular Biology, University of Wyoming , Laramie, WY , USA
| | - Rida Fatima
- Department of Molecular Biology, University of Wyoming , Laramie, WY , USA
| | - Jason P Gigley
- Department of Molecular Biology, University of Wyoming , Laramie, WY , USA
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18
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Romero-Pérez GA, Egashira M, Harada Y, Tsuruta T, Oda Y, Ueda F, Tsukahara T, Tsukamoto Y, Inoue R. Orally Administered Salacia reticulata Extract Reduces H1N1 Influenza Clinical Symptoms in Murine Lung Tissues Putatively Due to Enhanced Natural Killer Cell Activity. Front Immunol 2016; 7:115. [PMID: 27066007 PMCID: PMC4814808 DOI: 10.3389/fimmu.2016.00115] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2015] [Accepted: 03/14/2016] [Indexed: 01/29/2023] Open
Abstract
Influenza is a major cause of respiratory tract infection. Although most cases do not require further hospitalization, influenza periodically causes epidemics in humans that can potentially infect and kill millions of people. To countermeasure this threat, new vaccines need to be developed annually to match emerging influenza viral strains with increased resistance to existing vaccines. Thus, there is a need for finding and developing new anti-influenza viral agents as alternatives to current treatments. Here, we tested the antiviral effects of an extract from the stems and roots of Salacia reticulata (SSRE), a plant rich in phytochemicals, such as salacinol, kotalanol, and catechins, on H1N1 influenza virus-infected mice. Following oral administration of 0.6 mg/day of SSRE, the incidence of coughing decreased in 80% of mice, and only one case of severe pulmonary inflammation was detected. Moreover, when compared with mice given Lactobacillus casei JCM1134, a strain previously shown to help increase in vitro natural killer (NK) cell activity, SSRE-administered mice showed greater and equal NK cell activity in splenocytes and pulmonary cells, respectively, at high effector cell:target cell ratios. Next, to test whether or not SSRE would exert protective effects against influenza in the absence of gut microbiota, mice were given antibiotics before being inoculated influenza virus and subsequently administered SSRE. SSRE administration induced an increase in NK cell activity in splenocytes and pulmonary cells at levels similar to those detected in mice not treated with antibiotics. Based on our results, it can be concluded that phytochemicals in the SSRE exerted protective effects against influenza infection putatively via modulation of the immune response, including enhancement of NK cell activity, although some protective effects were not necessarily through modulation of gut microbiota. Further investigation is necessary to elucidate the molecular mechanisms underlying the protective effects of SSRE against influenza infection.
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Affiliation(s)
| | - Masayo Egashira
- Laboratory of Animal Science, Department of Agricultural and Life Sciences, Kyoto Prefectural University , Kyoto , Japan
| | - Yuri Harada
- Laboratory of Animal Science, Department of Agricultural and Life Sciences, Kyoto Prefectural University , Kyoto , Japan
| | - Takeshi Tsuruta
- Laboratory of Animal Science, Department of Agricultural and Life Sciences, Kyoto Prefectural University , Kyoto , Japan
| | - Yuriko Oda
- Life Science Research Laboratories, Research and Development Management Headquarters, Fujifilm Corporation , Kanagawa , Japan
| | - Fumitaka Ueda
- Life Science Research Laboratories, Research and Development Management Headquarters, Fujifilm Corporation , Kanagawa , Japan
| | - Takamitsu Tsukahara
- Kyoto Institute of Nutrition and Pathology, Kyoto, Japan; Laboratory of Animal Science, Department of Agricultural and Life Sciences, Kyoto Prefectural University, Kyoto, Japan
| | - Yasuhiro Tsukamoto
- Laboratory of Animal Hygiene, Department of Agricultural and Life Sciences, Kyoto Prefectural University , Kyoto , Japan
| | - Ryo Inoue
- Laboratory of Animal Science, Department of Agricultural and Life Sciences, Kyoto Prefectural University , Kyoto , Japan
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19
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Deroost K, Pham TT, Opdenakker G, Van den Steen PE. The immunological balance between host and parasite in malaria. FEMS Microbiol Rev 2015; 40:208-57. [PMID: 26657789 DOI: 10.1093/femsre/fuv046] [Citation(s) in RCA: 81] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/04/2015] [Indexed: 12/16/2022] Open
Abstract
Coevolution of humans and malaria parasites has generated an intricate balance between the immune system of the host and virulence factors of the parasite, equilibrating maximal parasite transmission with limited host damage. Focusing on the blood stage of the disease, we discuss how the balance between anti-parasite immunity versus immunomodulatory and evasion mechanisms of the parasite may result in parasite clearance or chronic infection without major symptoms, whereas imbalances characterized by excessive parasite growth, exaggerated immune reactions or a combination of both cause severe pathology and death, which is detrimental for both parasite and host. A thorough understanding of the immunological balance of malaria and its relation to other physiological balances in the body is of crucial importance for developing effective interventions to reduce malaria-related morbidity and to diminish fatal outcomes due to severe complications. Therefore, we discuss in this review the detailed mechanisms of anti-malarial immunity, parasite virulence factors including immune evasion mechanisms and pathogenesis. Furthermore, we propose a comprehensive classification of malaria complications according to the different types of imbalances.
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Affiliation(s)
- Katrien Deroost
- Laboratory of Immunobiology, Rega Institute for Medical Research, KU Leuven - University of Leuven, 3000 Leuven, Belgium The Francis Crick Institute, Mill Hill Laboratory, London, NW71AA, UK
| | - Thao-Thy Pham
- Laboratory of Immunobiology, Rega Institute for Medical Research, KU Leuven - University of Leuven, 3000 Leuven, Belgium
| | - Ghislain Opdenakker
- Laboratory of Immunobiology, Rega Institute for Medical Research, KU Leuven - University of Leuven, 3000 Leuven, Belgium
| | - Philippe E Van den Steen
- Laboratory of Immunobiology, Rega Institute for Medical Research, KU Leuven - University of Leuven, 3000 Leuven, Belgium
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20
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Sanou GS, Tiendrebeogo RW, Ouédraogo AL, Diarra A, Ouédraogo A, Yaro JB, Ouédraogo E, Verra F, Behr C, Troye-Blomberg M, Modiano D, Dolo A, Torcia MG, Traoré Y, Sirima SB, Nébié I. Haematological parameters, natural regulatory CD4 + CD25 + FOXP3+ T cells and γδ T cells among two sympatric ethnic groups having different susceptibility to malaria in Burkina Faso. BMC Res Notes 2012; 5:76. [PMID: 22283984 PMCID: PMC3292809 DOI: 10.1186/1756-0500-5-76] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2011] [Accepted: 01/27/2012] [Indexed: 01/22/2023] Open
Abstract
BACKGROUND Fulani ethnic group individuals are less susceptible than sympatric Mossi ethnic group, in term of malaria infection severity, and differ in antibody production against malaria antigens. The differences in susceptibility to malaria between Fulani and Mossi ethnic groups are thought to be regulated by different genetic backgrounds and offer the opportunity to compare haematological parameters, Tregs and γδT cell profiles in seasonal and stable malaria transmission settings in Burkina Faso. The study was conducted at two different time points i.e. during the high and low malaria transmission period. RESULTS Two cross-sectional surveys were undertaken in adults above 20 years belonging either to the Fulani or the Mossi ethnic groups 1) at the peak of the malaria transmission season and 2) during the middle of the low malaria transmission season. Full blood counts, proportions of Tregs and γδ T cells were measured at both time-points.As previously shown the Fulani and Mossi ethnic groups showed a consistent difference in P. falciparum infection rates and parasite load. Differential white blood cell counts showed that the absolute lymphocyte counts were higher in the Mossi than in the Fulani ethnic group at both time points. While the proportion of CD4+CD25high was higher in the Fulani ethnic group at the peak of malaria transmission season (p = 0.03), no clear pattern emerged for T regulatory cells expressing FoxP3+ and CD127low. However CD3+γδ+ subpopulations were found to be higher in the Fulani compared to the Mossi ethnic group, and this difference was statistically significant at both time-points (p = 0.004 at low transmission season and p = 0.04 at peak of transmission). CONCLUSION Our findings on regulatory T cell phenotypes suggest an interesting role for immune regulatory mechanisms in response to malaria. The study also suggests that TCRγδ + cells might contribute to the protection against malaria in the Fulani ethnic group involving their reported parasite inhibitory activities.
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Affiliation(s)
- Guillaume S Sanou
- Centre National de Recherche et de Formation sur le Paludisme, Ouagadougou, Burkina Faso.
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21
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de Carvalho EG, Böttger E, Hoang VT, Kremsner PG, Kun JFJ. Limited response of NK92 cells to Plasmodium falciparum-infected erythrocytes. Malar J 2011; 10:311. [PMID: 22018162 PMCID: PMC3213193 DOI: 10.1186/1475-2875-10-311] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2011] [Accepted: 10/21/2011] [Indexed: 12/04/2022] Open
Abstract
Background Mechanisms by which anti-malarial immune responses occur are still not fully clear. Natural killer (NK) cells are thought to play a pivotal role in innate responses against Plasmodium falciparum. In this study, the suitability of NK92 cells as models for the NK mechanisms involved in the immune response against malaria was investigated. Methods NK92 cells were assessed for several signs of activation and cytotoxicity due to contact to parasites and were as well examined by oligonucleotide microarrays for an insight on the impact P. falciparum-infected erythrocytes have on their transcriptome. To address the parasite side of such interaction, growth inhibition assays were performed including non-NK cells as controls. Results By performing microarrays with NK92 cells, the impact of parasites on a transcriptional level was observed. The findings show that, although not evidently activated by iRBCs, NK92 cells show transcriptional signs of priming and proliferation. In addition, decreased parasitaemia was observed due to co-incubation with NK92 cells. However, such effect might not be NK-specific since irrelevant cells also affected parasite growth in vitro. Conclusions Although NK92 cells are here shown to behave as poor models for the NK immune response against parasites, the results obtained in this study may be of use for future investigations regarding host-parasites interactions in malaria.
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22
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Grangeiro de Carvalho E, Bonin M, Kremsner PG, Kun JFJ. Plasmodium falciparum-infected erythrocytes and IL-12/IL-18 induce diverse transcriptomes in human NK cells: IFN-α/β pathway versus TREM signaling. PLoS One 2011; 6:e24963. [PMID: 21949811 PMCID: PMC3174986 DOI: 10.1371/journal.pone.0024963] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2011] [Accepted: 08/24/2011] [Indexed: 11/18/2022] Open
Abstract
The protective immunity of natural killer (NK) cells against malarial infections is thought to be due to early production of type II interferon (IFN) and possibly direct NK cell cytotoxicity. To better understand this mechanism, a microarray analysis was conducted on NK cells from healthy donors PBMCs that were co-cultured with P. falciparum 3D7-infected erythrocytes. A very similar pattern of gene expression was observed among all donors for each treatment in three replicas. Parasites particularly modulated genes involved in IFN-α/β signaling as well as molecules involved in the activation of interferon regulatory factors, pathways known to play a role in the antimicrobial immune response. This pattern of transcription was entirely different from that shown by NK cells treated with IL-12 and IL-18, in which IFN-γ- and TREM-1-related genes were over-expressed. These results suggest that P. falciparum parasites and the cytokines IL-12 and IL-18 have diverse imprints on the transcriptome of human primary NK cells. IFN-α-related genes are the prominent molecules induced by parasites on NK cells and arise as candidate biomarkers that merit to be further investigated as potential new tools in malaria control.
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MESH Headings
- Biomarkers/metabolism
- Blotting, Western
- Computational Biology
- Cytokines/genetics
- Cytokines/metabolism
- Erythrocytes/immunology
- Erythrocytes/parasitology
- Flow Cytometry
- Gene Expression Profiling
- Humans
- Interferon-alpha/genetics
- Interferon-alpha/metabolism
- Interferon-gamma/genetics
- Interferon-gamma/metabolism
- Interleukin-12/pharmacology
- Interleukin-18/pharmacology
- Killer Cells, Natural/drug effects
- Killer Cells, Natural/metabolism
- Killer Cells, Natural/parasitology
- Lymphocyte Activation
- Malaria, Falciparum/immunology
- Malaria, Falciparum/metabolism
- Malaria, Falciparum/parasitology
- Membrane Glycoproteins/genetics
- Membrane Glycoproteins/metabolism
- Oligonucleotide Array Sequence Analysis
- Plasmodium falciparum/genetics
- Plasmodium falciparum/immunology
- RNA, Messenger/genetics
- Real-Time Polymerase Chain Reaction
- Receptors, Immunologic/genetics
- Receptors, Immunologic/metabolism
- Signal Transduction
- Triggering Receptor Expressed on Myeloid Cells-1
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Leishmania-infected macrophages are targets of NK cell-derived cytokines but not of NK cell cytotoxicity. Infect Immun 2011; 79:2699-708. [PMID: 21518784 DOI: 10.1128/iai.00079-11] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
Natural killer (NK) cells are important components of a protective immune response against intracellular pathogens such as Leishmania parasites, which reside within myeloid cells. Previous in vivo studies in murine cutaneous or visceral leishmaniasis showed that NK cells are activated by conventional dendritic cells in a Toll-like receptor 9-, interleukin-12 (IL-12)-, and IL-18-dependent manner during the early phase of infection and help to restrict the tissue parasite burden by unknown mechanisms. Here, we tested whether NK cells contribute to the control of Leishmania infections by lysing or by activating infected host cells. Coculture experiments revealed that activated NK cells from poly(I:C)-treated mice readily killed tumor target cells, whereas Leishmania infantum- or L. major-infected macrophages or dendritic cells remained viable. Infection with Leishmania did not significantly alter the expression of NK cell-activating molecules (retinoic acid early transcript alpha [Rae-1α], mouse UL16-binding protein-like transcript 1 [MULT-1], CD48) or inhibitory molecules (major histocompatibility complex [MHC] class I, nonclassical MHC class 1b molecule Qa-1) on the surface of myeloid cells, which offers an explanation for their protection from NK cell cytotoxicity. Consistent with these in vitro data, in vivo cytotoxicity assays revealed poor cytolytic activity of NK cells against adoptively transferred infected wild-type macrophages, whereas MHC class I-deficient macrophages were efficiently eliminated. NK cells activated by IL-12 and IL-18 stimulated macrophages to kill intracellular Leishmania in a cell contact-independent but gamma interferon-, tumor necrosis factor-, and inducible nitric oxide synthase-dependent manner. We conclude that Leishmania parasites, unlike viruses, do not render infected myeloid cells susceptible to the cytotoxicity of NK cells. Instead, soluble products of NK cells trigger the leishmanicidal activity of macrophages.
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D'Ombrain MC, Voss TS, Maier AG, Pearce JA, Hansen DS, Cowman AF, Schofield L. Plasmodium falciparum erythrocyte membrane protein-1 specifically suppresses early production of host interferon-gamma. Cell Host Microbe 2007; 2:130-8. [PMID: 18005727 DOI: 10.1016/j.chom.2007.06.012] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2007] [Revised: 06/12/2007] [Accepted: 06/28/2007] [Indexed: 11/16/2022]
Abstract
Plasmodium falciparum erythrocyte membrane protein-1 (PfEMP-1) is a variable antigen expressed by P. falciparum, the malarial parasite. PfEMP-1, present on the surface of infected host erythrocytes, mediates erythrocyte binding to vascular endothelium, enabling the parasite to avoid splenic clearance. In addition, PfEMP-1 is proposed to regulate host immune responses via interactions with the CD36 receptor on antigen-presenting cells. We investigated the immunoregulatory function of PfEMP-1 by comparing host cell responses to erythrocytes infected with either wild-type parasites or transgenic parasites lacking PfEMP-1. We showed that PfEMP-1 suppresses the production of the cytokine interferon-gamma by human peripheral blood mononuclear cells early after exposure to P. falciparum. Suppression of this rapid proinflammatory response was CD36 independent and specific to interferon-gamma production by gammadelta-T, NK, and alphabeta-T cells. These data demonstrate a parasite strategy for downregulating the proinflammatory interferon-gamma response and further establish transgenic parasites lacking PfEMP-1 as powerful tools for elucidating PfEMP-1 functions.
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Affiliation(s)
- Marthe C D'Ombrain
- Infection and Immunity Division, The Walter and Eliza Hall Institute of Medical Research, 1G Royal Parade, Parkville, Victoria 3050, Australia
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25
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Achtman AH, Stephens R, Cadman ET, Harrison V, Langhorne J. Malaria-specific antibody responses and parasite persistence after infection of mice with Plasmodium chabaudi chabaudi. Parasite Immunol 2007; 29:435-44. [PMID: 17727567 DOI: 10.1111/j.1365-3024.2007.00960.x] [Citation(s) in RCA: 58] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
While it is known that antibodies are critical for clearance of malaria infections, it is not clear whether adequate antibody responses are maintained and what effect chronic infection has on this response. Here we show that mice with low-grade chronic primary infections of Plasmodium chabaudi or infections very recently eliminated have reduced second infections when compared with the second infection of parasite-free mice. We also show that parasite-specific antibody responses induced by infection of mice with Plasmodium chabaudi contain both short- and long-lived components as well as memory B cells responsible for a faster antibody response during re-infection. Furthermore, parasite-specific antibodies to the C-terminal fragment of merozoite surface protein-1 (MSP-1) undergo avidity maturation. However, antibodies with both low and high avidity persist throughout infection and after re-infection, suggesting repeated rounds of activation and maturation of memory B cells. Neither the avidity profile of the antibody response, nor its maintenance is affected by persisting live parasites. Therefore, differences in parasitemia in re-infection cannot be explained solely by higher levels of antibody or greater affinity maturation of malaria-specific antibodies. These data suggest that there may be an antibody-independent component to the early control of secondary infections in mice that are chronically infected.
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Affiliation(s)
- A H Achtman
- Division of Parasitology, National Institute for Medical Research, The Ridgeway, Mill Hill, London, UK
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26
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Hansen DS, D'Ombrain MC, Schofield L. The role of leukocytes bearing Natural Killer Complex receptors and Killer Immunoglobulin-like Receptors in the immunology of malaria. Curr Opin Immunol 2007; 19:416-23. [PMID: 17702559 DOI: 10.1016/j.coi.2007.07.011] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2007] [Accepted: 07/05/2007] [Indexed: 10/22/2022]
Abstract
The biology of Natural Killer (NK) cells and other NK Receptor (NKR)(+) leukocytes has largely been elucidated in viral or cancer systems, and involvement in other diseases or infectious states is less clearly defined. Recently, however, clear evidence has emerged for a role in malaria. NK cells and NKR(+) leukocytes significantly control susceptibility and resistance to both malaria infection and severe disease syndromes in murine models, in dependence upon receptors encoded within the Natural Killer Complex (NKC). Plasmodium falciparum can rapidly activate human NKR(+) gammadelta T cells and NK cells in vitro, and these responses are controlled partly by NKR loci encoded within the human syntenic NKC and Killer Immunoglobulin-like Receptor (KIR) genomic regions. Neither erythrocytes nor malaria parasites express HLA or MHC Class I-like homologues, or obvious stress-type ligands, suggesting the possibility of novel NKR recognition mechanisms. Parasite-derived ligands such as P. falciparum Erythrocyte Membrane Protein-1 (PfEMP-1) and glycosylphosphatidylinositol (GPI) regulate some of these diverse responses. Population-based immunogenetic analyses should allow the identification of NKC and KIR loci controlling innate and adaptive immune responses to malaria and associated with altered risk of infection and disease.
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Affiliation(s)
- Diana S Hansen
- The Walter and Eliza Hall Institute of Medical Research, 1G, Royal Parade, Parkville 3050, Victoria, Australia
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27
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Schofield L. Intravascular infiltrates and organ-specific inflammation in malaria pathogenesis. Immunol Cell Biol 2007; 85:130-7. [PMID: 17344907 DOI: 10.1038/sj.icb.7100040] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Malaria infects 5-10% of humanity and causes around two million deaths annually, mostly in children. The disease is of significant interest to immunologists, as acquired host immunity can limit the clinical impact of infection and partially reduces parasite replication; however, immunological reactions also contribute significantly to pathogenesis and fatalities. This review addresses the view that immunopathology in severe malaria arises predominantly from intravascular lesions resulting from a pathogen-initiated cascade of activated immune effector and regulatory cells infiltrating the vascular beds of diverse target organs, including bone marrow, spleen, brain, placenta and lungs. The main feature distinguishing these processes from classical cellular inflammation is the absence of extravasation, resulting from the intravascular location of the pathogen. Clinical and epidemiological observations combined with experimental infections in animal models suggest that parasite 'molecular patterns' or toxins cause cytokine and chemokine enhancement of infiltrates, composed of macrophages, neutrophils, natural killer (NK) cells, invariant natural killer T (iNKT) cells, gamma/delta T cells and both CD4(+) and CD8(+) effector T cells, leading to local vascular and organ derangement. Diverse pattern recognition and NK receptors crucially regulate these responding cell populations. Thus, innate immune mechanisms lie at the heart of this massive global public health problem.
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Affiliation(s)
- Louis Schofield
- The Walter and Eliza Hall Institute of Medical Research, Parkville, Victoria, Australia.
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28
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Delahaye NF, Barbier M, Fumoux F, Rihet P. Association analyses of NCR3 polymorphisms with P. falciparum mild malaria. Microbes Infect 2007; 9:160-6. [PMID: 17208487 DOI: 10.1016/j.micinf.2006.11.002] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2006] [Revised: 11/01/2006] [Accepted: 11/07/2006] [Indexed: 11/28/2022]
Abstract
Plasmodium falciparum malaria is a major cause of morbidity and mortality in many developing countries especially in sub-Saharan Africa. A susceptibility locus for mild malaria has been mapped to the MHC region, and TNF polymorphisms have been associated with mild malaria. The Natural Cytotoxicity-triggering Receptor 3 (NCR3) gene is located in the peak region of linkage, and is 15kb distal to TNF. In this study, we considered NCR3 as a candidate gene, and we genotyped ten NCR3 single nucleotide polymorphisms (SNPs). Here, we report evidence of an association between mild malaria and NCR3 -412G>C polymorphism located within the promoter. Population-based association analysis showed that NCR3 -412C carriers had more frequent mild malaria attacks than NCR3 -412GG individuals (P=0.001). Using the family-based association test (FBAT) program and its phenotype (PBAT) option, we further found that NCR3 -412C (P=0.0009) and a haplotype containing NCR3 -412C (P=0.008) were significantly associated with increased risk of mild malaria, and that the association was not due to the association of TNF with mild malaria. These observations suggest that there are at least two genes located on the central region of MHC involved in genetic control of human malaria. The association of NCR3 with malaria should provide new insights into the role of Natural Killer cells in this common disease.
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Affiliation(s)
- Nicolas F Delahaye
- Université de la Méditerranée, IFR 48, Faculté de Pharmacie, Laboratoire de Pharmacogénétique des Maladies Parasitaires-EA 864, 27 Bd Jean Moulin 13385 Marseille, France
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29
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Abstract
Malaria, caused by the infection with parasites of the germs Plasmodium, is one of the three most important infectious diseases worldwide, along with tuberculosis and infection with human immunodeficiency virus. Natural killer (NK) cells are lymphocytes classically involved in the early defense against viral infections and intracytoplasmic bacterial infections and are also implicated during the course of tumor development and allogeneic transplantation. These cells display important cytotoxic activity and produce high levels of proinflammatory cytokines. In both mouse and human models of malaria, NK cells appear to be a major source of interferon-gamma during the early phase of infection. In humans, indirect signaling through monocytes/macrophages required to optimally stimulate NK cell activity. However, the in vivo functions of NK cells during malaria are still enigmatic, and many issues remain to be dissected, such as the molecular basis of the direct recognition of iRBCs by NK cells.
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Affiliation(s)
- Sophie Roetynck
- Centre d'Immunologie de Marseille-Luminy, Université de la Méditerranée, Marseille, France
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30
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Abstract
Innate immune response against Plasmodium falciparum (Pf), a causative agent of human malaria, is the result of several thousand years of co-evolution between the parasite and his host. An early IFN-gamma production during infection is associated with a better evolution of the disease. Natural killer (NK) cells are among the first cells in peripheral blood to produce IFN-gamma in response to Pf-infected erythrocytes (Pf-E). NK cells are found in blood, in secondary lymphoid organs as well as in peripheral non-lymphoid tissues. They participate in host innate responses that occur upon viral and intracytoplasmic bacterial infections, but also during the course of tumor development and allogeneic transplantation. These lymphocytes are not only important players of innate effector responses, but also participate in the initiation and development of adaptive immune responses. In addition, direct sensing of Pf infection by NK cells induces their production of the proinflammatory chemokine IL-8, suggesting a role for NK cells in the recruitment and the activation of other cells during malaria infection. Several other cell subsets are involved in the innate immune response to Pf. Dendritic cells, macrophages, gamma delta T cells, NKT cells are able to sense the presence of the parasite. Along this line, the presence of IL-12 is necessary to NK cell IFN-gamma production and a functional cooperation takes place between macrophages and NK cells in the context of this parasitic infection. In particular, IL-18 produced by macrophages is a key factor for this NK response. However, the molecular basis of Pf-E recognition by NK cells as well as the functional role of NK cell responses during the course of the disease remain to be adressed.
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Affiliation(s)
- Sophie Roetynck
- Centre d'Immunologie de Marseille-Luminy, Inserm-CNRS, Université de la Méditerranée, Parc Scientifique et Technologique de Luminy, Case 906, 13288 Marseille Cedex 09, France
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31
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Boysen P, Klevar S, Olsen I, Storset AK. The protozoan Neospora caninum directly triggers bovine NK cells to produce gamma interferon and to kill infected fibroblasts. Infect Immun 2006; 74:953-60. [PMID: 16428740 PMCID: PMC1360307 DOI: 10.1128/iai.74.2.953-960.2006] [Citation(s) in RCA: 51] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Natural killer (NK) cells are considered to be key players in the early innate responses to protozoan infections, primarily indirectly by producing gamma interferon (IFN-gamma) in response to cytokines, like interleukin 12 (IL-12). We demonstrate that live, as well as heat-inactivated, tachyzoites of Neospora caninum, a Toxoplasma-like protozoan, directly trigger production of IFN-gamma from purified, IL-2-activated bovine NK cells. This response occurred independently of IL-12 but was increased by the addition of the cytokine. A similar IFN-gamma response was measured in cocultures of NK cells and N. caninum-infected autologous fibroblasts. However, no NK cell-derived IFN-gamma response was detected when cells were cultured with soluble antigens from the organism, indicating that intact tachyzoites or nonsoluble components are necessary for NK cell triggering. Furthermore, N. caninum-infected autologous fibroblasts had increased susceptibility to NK cell cytotoxicity compared to uninfected fibroblasts. This cytotoxicity was largely mediated by a perforin-mediated mechanism. The activating receptor NKp46 was involved in cytotoxicity against fibroblasts but could not explain the increased cytotoxicity against infected targets. Interestingly, N. caninum tachyzoites were able to infect cultured NK cells, in which tachyzoites proliferated inside parasitophorous vacuoles. Together, these findings underscore the role of NK cells as primary responders during a protozoan infection, describe intracellular protozoan infection of NK cells in vitro for the first time, and represent the first functional study of purified bovine NK cells in response to infection.
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Affiliation(s)
- Preben Boysen
- Department of Food Safety and Infection Biology, Norwegian School of Veterinary Science, P.O. Box 8146 Dep., N-0033 Oslo, Norway
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32
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Carrington M, Martin MP. The impact of variation at the KIR gene cluster on human disease. Curr Top Microbiol Immunol 2006; 298:225-57. [PMID: 16329188 DOI: 10.1007/3-540-27743-9_12] [Citation(s) in RCA: 72] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Leukocyte behavior is controlled by a balance of inhibitory and stimulatory signals generated on ligand binding to a complex set of receptors located on the cell surface. The killer cell immunoglobulin-like receptor (KIR) genes encode one such, family of receptors expressed by natural killer (NK) cells, key components of the innate immune system that participate in early responses against infected or transformed cells through production of cytokines and direct cytotoxicity. KIRs are also expressed on a subset of T cells, where they contribute to the intensity of acquired immune responses. Recognition of self HLA class I ligands by inhibitory KIR allows NK cells to identify normal cells, preventing an NK cell-mediated response against healthy autologous cells. Activation of NK cells through stimulatory receptors is directed toward cells with altered expression of class I, a situation characteristic of some virally infected cells and tumor cells. The "missing self" model for NK cell activation was proposed to explain killing of cells that express little or no class I, while cells expressing normal levels of class I are spared. Studies performed over the last several years have revealed extensive diversity at the KIR gene locus, which stems from both its polygenic (variable numbers of genes depending on KIR haplotype) and multiallelic polymorphism. Given the role of KIR in both arms of the immune response, their specificity for HLA class I allotypes, and their extensive genomic diversity, it is reasonable to imagine that KIR gene variation affects resistance and susceptibility to the pathogenesis of numerous diseases. Consequently, the evolution of KIR locus diversity within and across populations may be a function of disease morbidity and mortality. Here we review a growing body of evidence purporting the influence of KIR polymorphism in human disease.
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Affiliation(s)
- M Carrington
- Basic Research Program, SAIC-Frederick Inc., Laboratory of Genomic Diversity, National Cancer Institute, Bldg. 560 Rm. 21-89, P.O. Box B, Frederick, MD 21702, USA.
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33
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Urban BC, Ing R, Stevenson MM. Early interactions between blood-stage plasmodium parasites and the immune system. Curr Top Microbiol Immunol 2005; 297:25-70. [PMID: 16265902 DOI: 10.1007/3-540-29967-x_2] [Citation(s) in RCA: 60] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Accumulating evidence provides strong support for the importance of innate immunity in shaping the subsequent adaptive immune response to blood-stage Plasmodium parasites, the causative agents of malaria. Early interactions between blood-stage parasites and cells of the innate immune system, including dendritic cells, monocytes/macrophages, natural killer (NK) cells, NKT cells, and gamma6 T cells, are important in the timely control of parasite replication and in the subsequent elimination and resolution of the infection. The major role of innate immunity appears to be the production of immunoregulatory cytokines, such as interleukin (IL)-12 and interferon (IFN)-gamma, which are critical for the development of type 1 immune responses involving CD4+ Thl cells, B cells, and effector cells which mediate cell-mediated and antibody-dependent adaptive immune responses. In addition, it is likely that cells of the innate immune system, especially dendritic cells, serve as antigen-presenting cells. Here, we review recent data from rodent models of blood-stage malaria and from human studies, and outline the early interactions of infected red blood cells with the innate immune system. We compare and contrast the results derived from studies in infected laboratory mice and humans. These host species are sufficiently different with respect to the identity of the infecting Plasmodium species, the resulting pathologies, and immune responses, particularly where the innate immune response is concerned. The implications of these findings for the development of an effective and safe malaria vaccine are also discussed.
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Affiliation(s)
- B C Urban
- Centre for Clinical Vaccinology and Tropical Medicine, Nuffield Department of Clinical Medicine, Oxford University, Churchill Hospital, Old Road, Oxford, UK.
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34
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Sartelet H, Schleiermacher D, Le-Hesran JY, Graesslin O, Gaillard D, Fe M, Lechki C, Gaye A, Le Bouteiller P, Birembaut P. Less HLA-G expression in Plasmodium falciparum-infected third trimester placentas is associated with more natural killer cells. Placenta 2005; 26:505-11. [PMID: 15950065 DOI: 10.1016/j.placenta.2004.08.006] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 08/17/2004] [Indexed: 10/26/2022]
Abstract
During pregnancy, maternal immune tolerance of the fetal semi-allogeneic graft is partly the consequence of extravillous trophoblast HLA-G expression and its interaction with natural killer (NK) cells. Plasmodium falciparum malaria is frequently associated with maternal and fetal complications. Local HLA-G expression and the number of NK cells were evaluated immunohistochemically in P. falciparum-infected and uninfected placentas (15 each) collected in a seasonal malaria-hypoendemic area. In control placentas, HLA-G was almost always expressed in extravillous trophoblast whereas, in infected placentas, it was significantly more weakly expressed in extravillous trophoblast but was also detected in intervillous space macrophages. NK cells were evaluated in intervillous and intravillous spaces and in basal plate. NK cells were always more abundant in basal plate than in intervillous and intravillous spaces in infected or control placentas. For each area, more NK cells were seen in infected than control placentas. These data suggest that HLA-G down-regulation and more NK cells in placentas may be among the mechanisms involved in poor birth outcome associated with P. falciparum infection.
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Affiliation(s)
- H Sartelet
- Laboratoire Pol Bouin, Centre Hospitalier Universitaire de Reims, Reims, France.
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35
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Abstract
Malaria is possibly the most serious infectious disease of humans, infecting 5-10% of the world's population, with 300-600 million clinical cases and more than 2 million deaths annually. Adaptive immune responses in the host limit the clinical impact of infection and provide partial, but incomplete, protection against pathogen replication; however, these complex immunological reactions can contribute to disease and fatalities. So, appropriate regulation of immune responses to malaria lies at the heart of the host-parasite balance and has consequences for global public health. This Review article addresses the innate and adaptive immune mechanisms elicited during malaria that either cause or prevent disease and fatalities, and it considers the implications for vaccine design.
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Affiliation(s)
- Louis Schofield
- The Walter and Eliza Hall Institute of Medical Research, 1G Royal Parade, Parkville, Victoria 3050, Australia.
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36
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Baratin M, Roetynck S, Lépolard C, Falk C, Sawadogo S, Uematsu S, Akira S, Ryffel B, Tiraby JG, Alexopoulou L, Kirschning CJ, Gysin J, Vivier E, Ugolini S. Natural killer cell and macrophage cooperation in MyD88-dependent innate responses to Plasmodium falciparum. Proc Natl Acad Sci U S A 2005; 102:14747-52. [PMID: 16203971 PMCID: PMC1253601 DOI: 10.1073/pnas.0507355102] [Citation(s) in RCA: 122] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
IFN-gamma secretion by natural killer (NK) cells is pivotal to several tumor and viral immune responses, during which NK and dendritic cells cooperation is required. We show here that macrophages are mandatory for NK cell IFN-gamma secretion in response to erythrocytes infected with Plasmodium falciparum (Pf), a causative agent of human malaria. In addition, direct sensing of Pf infection by NK cells induces their production of the proinflammatory chemokine CXCL8, without triggering their granule-mediated cytolytic programs. Despite their reported role in Pf recognition, Toll-like receptor (TLR) 2, TLR9, and TLR11 are individually dispensable for NK cell activation induced by Pf-infected erythrocytes. However, IL-18R expression on NK cells, IL-18 production by macrophages, and MyD88 on both cell types are essential components of this previously undescribed pathway of NK cell activation in response to a parasite infection.
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Affiliation(s)
- Myriam Baratin
- Centre d'Immunologie de Marseille-Luminy, Institut National de la Santé et de la Recherche Médicale, Centre National de la Recherche Scientifique, Université delaMéditerranée, 13288 Marseille, France
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37
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Abstract
For a long time, the family of type I interferons (IFN-alpha/beta) has received little attention outside the fields of virology and tumor immunology. In recent years, IFN-alpha/beta regained the interest of immunologists, due to the phenotypic and functional characterization of IFN-alpha/beta-producing cells, the definition of novel immunomodulatory functions and signaling pathways of IFN-alpha/beta, and the observation that IFN-alpha/beta not only exerts antiviral effects but is also relevant for the pathogenesis or control of certain bacterial and protozoan infections. This review summarizes the current knowledge on the production and function of IFN-alpha/beta during non-viral infections in vitro and in vivo.
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Affiliation(s)
- Christian Bogdan
- Institute of Medical Microbiology and Hygiene, Department of Microbiology and Hygiene, University of Freiburg, Freiburg, Germany.
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38
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Mavoungou E, Bouyou-Akotet MK, Kremsner PG. Effects of prolactin and cortisol on natural killer (NK) cell surface expression and function of human natural cytotoxicity receptors (NKp46, NKp44 and NKp30). Clin Exp Immunol 2005; 139:287-96. [PMID: 15654827 PMCID: PMC1809301 DOI: 10.1111/j.1365-2249.2004.02686.x] [Citation(s) in RCA: 56] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
Abstract
The surface density of the triggering receptors (e.g. NKp46 and NKp30) responsible for natural killer (NK) cell-mediated cytotoxicity determines the ability of NK cells to kill susceptible target cells. In this study, we show that prolactin up-regulates and cortisol down-regulates the surface expression of NKp46 and NKp30. The prolactin-mediated activation and the cortisol-mediated inhibition of natural cytotoxicity receptor (NCR) surface expression reflects gene regulation at the transcriptional level. NKp46 and NKp30 are the major receptors involved in the NK-mediated killing of K562, a human chronic myelogenous leukaemia cell line. Accordingly, the prolactin dramatically increased the NK-mediated killing of the K562 cell line, whereas cortisol abolished this activity. Our data suggest a mechanism by which prolactin activates the lytic function of NK cells, and cortisol inhibits the NK-mediated attack.
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MESH Headings
- Cell Line, Tumor
- Cytotoxicity Tests, Immunologic
- Flow Cytometry
- Gene Expression/drug effects
- Humans
- Hydrocortisone/pharmacology
- Killer Cells, Natural/immunology
- Leukemia, Myelogenous, Chronic, BCR-ABL Positive/immunology
- Leukemia, Myelogenous, Chronic, BCR-ABL Positive/therapy
- Lymphocyte Activation
- Membrane Glycoproteins/genetics
- Membrane Glycoproteins/metabolism
- Natural Cytotoxicity Triggering Receptor 1
- Natural Cytotoxicity Triggering Receptor 2
- Natural Cytotoxicity Triggering Receptor 3
- Prolactin/pharmacology
- Receptors, Antigen, T-Cell/metabolism
- Receptors, Immunologic/genetics
- Receptors, Immunologic/metabolism
- Reverse Transcriptase Polymerase Chain Reaction
- Statistics, Nonparametric
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Affiliation(s)
- E Mavoungou
- Medical Research Unit, Albert Schweitzer Hospital, Lambaréné, Gabon.
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39
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Korbel DS, Finney OC, Riley EM. Natural killer cells and innate immunity to protozoan pathogens. Int J Parasitol 2004; 34:1517-28. [PMID: 15582528 DOI: 10.1016/j.ijpara.2004.10.006] [Citation(s) in RCA: 74] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2004] [Revised: 09/16/2004] [Accepted: 10/06/2004] [Indexed: 10/26/2022]
Abstract
Natural killer (NK) cells are lymphoid cells that mediate significant cytotoxic activity and produce high levels of pro-inflammatory cytokines in response to infection. During viral infection, NK cell cytotoxicity and cytokine production is induced principally by monocyte-macrophage- and dendritic cell-derived cytokines but virally encoded ligands for NK cells are also beginning to be described. NK derived interferon-gamma (IFN-gamma) production is also essential for control of several protozoal infections including toxoplasmosis, trypanosomiasis, leishmaniasis and malaria. The activation of NK cells by protozoan pathogens is also believed to be cytokine-mediated although some recent studies suggest that direct recognition of parasites by NK cells also occurs. Both indirect signalling via accessory cell-derived cytokines and direct signalling, presumably through NK receptors, are needed in order for human malaria parasites (Plasmodium falciparum) to optimally stimulate NK activity.
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Affiliation(s)
- Daniel S Korbel
- Department of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, Keppel Street, London WC1E 7HT, UK
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40
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Wideman RF, Chapman ME, Wang W, Erf GF. Immune modulation of the pulmonary hypertensive response to bacterial lipopolysaccharide (endotoxin) in broilers. Poult Sci 2004; 83:624-37. [PMID: 15109060 DOI: 10.1093/ps/83.4.624] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023] Open
Abstract
The lungs of broilers are constantly challenged with lipopolysaccharide (LPS, endotoxin) that can activate leukocytes and trigger thromboxane A2 (TxA2)- and serotonin (5HT)-mediated pulmonary vasoconstriction leading to pulmonary hypertension. Among broilers from a single genetic line, some individuals respond to LPS with large increases in pulmonary arterial pressure, whereas others fail to exhibit any response to the same supramaximal dose of LPS. This extreme variability in the pulmonary hypertensive response to LPS appears to reflect variability in the types or proportions of chemical mediators released by leukocytes. Our research has confirmed that TxA2 and 5HT are potent pulmonary vasoconstrictors in broilers and that broilers hatched and reared together consistently exhibit pulmonary hypertension after i.v. injections of TxA2 or 5HT. Previous in vitro studies conducted using macrophages from different lines of chickens demonstrated innate variability in the LPS-stimulated induction of nitric oxide synthase (iNOS) followed by the onset of an LPS-refractory state. The NOS enzyme converts arginine to citrulline and nitric oxide (NO). It is known that NO produced by endothelial NOS serves as a key modulator of flow-dependent pulmonary vasodilation, and it is likely that NO generated by iNOS also contributes to the pulmonary vasodilator response. Accordingly, it is our hypothesis that the pulmonary hypertensive response to LPS in broilers is minimal when more vasodilators (NO, prostacyclin) than vasoconstrictors (TxA2, 5HT) are generated during an LPS challenge. Indeed, inhibiting NO production through pharmacological blockade of NOS with the inhibitor Nomega-nitro-L-arginine methyl ester modestly increased the baseline pulmonary arterial pressure and dramatically increased the pulmonary hypertensive response to LPS in all broilers evaluated. Innate differences in the effect of LPS on the pulmonary vasculature may contribute to differences in susceptibility of broilers to pulmonary hypertension syndrome (ascites).
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Affiliation(s)
- R F Wideman
- Department of Poultry Science, University of Arkansas, Fayetteville, Arkansas 72701, USA.
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41
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Affiliation(s)
- Mary M Stevenson
- Centre for the Study of Host Resistance, McGill University Health Centre Research Institute and Department of Medicine, McGill University, 1650 Cedar Avenue, Montreal, Quebec, H3G 1A4, Canada.
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42
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Bouyou-Akotet MK, Issifou S, Meye JF, Kombila M, Ngou-Milama E, Luty AJF, Kremsner PG, Mavoungou E. Depressed Natural Killer Cell Cytotoxicity againstPlasmodium falciparum–Infected Erythrocytes during First Pregnancies. Clin Infect Dis 2004; 38:342-7. [PMID: 14727203 DOI: 10.1086/380646] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2003] [Accepted: 09/09/2003] [Indexed: 11/04/2022] Open
Abstract
We measured natural killer (NK) cell cytotoxicity and cortisol and prolactin concentrations in peripheral venous blood samples obtained from pregnant Gabonese women at the time of delivery. The NK cell-mediated cytotoxicity against Plasmodium falciparum-infected erythrocytes in vitro was lower in samples obtained from primiparous women than in samples obtained from multiparous women; cortisol concentrations were significantly higher in primiparous women than in multiparous women, and prolactin concentrations were significantly lower. The highest cortisol concentrations were found in the plasma of P. falciparum-infected primiparous women. A positive correlation was found between cortisol concentration and parasite load; an inverse correlation was found between the magnitude of the NK cell cytolytic effect and cortisol production. A positive correlation was found between this effect and prolactin production. Thus, depressed NK cell cytotoxicity against P. falciparum-infected erythrocytes is correlated with high cortisol concentrations and may contribute to increased susceptibility to malaria during pregnancy.
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Rhee MS, Akanmori BD, Waterfall M, Riley EM. Changes in cytokine production associated with acquired immunity to Plasmodium falciparum malaria. Clin Exp Immunol 2001; 126:503-10. [PMID: 11737069 PMCID: PMC1906215 DOI: 10.1046/j.1365-2249.2001.01681.x] [Citation(s) in RCA: 44] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Individuals living in malaria-endemic areas eventually develop clinical immunity to Plasmodium falciparum. That is, they are able to limit blood parasite densities to extremely low levels and fail to show symptoms of infection. As the clinical symptoms of malaria infection are mediated in part by pro-inflammatory cytokines it is not clear whether the acquisition of clinical immunity is due simply to the development of antiparasitic mechanisms or whether the ability to regulate inflammatory cytokine production is also involved. We hypothesize that there is a correlation between risk of developing clinical malaria and the tendency to produce high levels of proinflammatory cytokines in response to malaria infection. In order to test this hypothesis, we have compared the ability of peripheral blood mononuclear cells from malaria-naive and malaria-exposed adult donors to proliferate and to secrete IFN-gamma in response to P. falciparum schizont extract (PfSE). In order to determine how PfSE-induced IFN-gamma production is regulated, we have also measured production of IL-12p40 and IL-10 from PfSE-stimulated PBMC and investigated the role of neutralizing antibody to IL-12 in modulating IFN-gamma production. We find that cells from naive donors produce moderate amounts of IFN-gamma in response to PfSE and that IFN-gamma production is strongly IL-12 dependent. Cells from malaria-exposed donors living in an area of low malaria endemicity produce much higher levels of IFN-gamma and this response is also at least partially IL-12 dependent. In complete contrast, cells from donors living in an area of very high endemicity produce minimal amounts of IFN-gamma. No significant differences were detected between the groups in IL-10 production, suggesting that this cytokine does not play a major role in regulating malaria-induced IFN-gamma production. The data from this study thus strongly support the hypothesis that down-regulation of inflammatory cytokine production may be a component of acquired clinical immunity to malaria but the mechanism by which this is achieved remains to be elucidated.
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Affiliation(s)
- M S Rhee
- Institute of Cell, Animal and Population Biology, Division of Biological Sciences, University of Edinburgh, Edinburgh, UK
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Yoder BJ, Goodrum KJ. Plasmodium chabaudi chabaudi: B-1 cell expansion correlates with semiresistance in BALB/cJ mice. Exp Parasitol 2001; 98:71-82. [PMID: 11465990 DOI: 10.1006/expr.2001.4622] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The largest obstacle impeding the development of an effective malaria vaccine is the incomplete understanding of how the immune response is regulated during infection. B-1a cells, a poorly understood subcategory of B lymphocytes, produce nonpathologic autoantibodies of low affinity which have been shown to have distinct immunoregulatory capabilities. What the exact activity of B-1a cells are during the course of malaria has yet to be determined. By use of flow cytometry, it was observed that B-1a cells significantly expand by day 3 postinfection in the spleen and peritoneum of Plasmodium chabaudi chabaudi semiresistant BALB/cJ mice, but not until day 8 postinfection in the spleen of P. chabaudi chabaudi fully susceptible BALB/cByJ mice. The activation of B-1a cells was also demonstrated by the measurement of natural autoantibody IgM production from the serum and cultured peritoneal B-1a cells. Infected semiresistant BALB/cJ mice generated higher levels of anti-ssDNA IgM antibodies than infected fully susceptible BALB/cByJ mice. The preliminary data presented here suggest a possible roll of B-1 cells in contributing to the successful survival of murine malarial infection.
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Affiliation(s)
- B J Yoder
- Department of Biomedical Sciences, Ohio University College of Osteopathic Medicine, Irvine Hall, Athens, Ohio 45701, USA.
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Kurtis JD, Mtalib R, Onyango FK, Duffy PE. Human resistance to Plasmodium falciparum increases during puberty and is predicted by dehydroepiandrosterone sulfate levels. Infect Immun 2001; 69:123-8. [PMID: 11119497 PMCID: PMC97863 DOI: 10.1128/iai.69.1.123-128.2001] [Citation(s) in RCA: 72] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Immunity to Plasmodium falciparum develops slowly in areas of endemicity, and this is often ascribed to poorly immunogenic or highly variant parasite antigens. However, among populations newly exposed to malaria, adults acquire immunity more rapidly than children. We examined the relationship between pubertal development and resistance to P. falciparum. During two transmission seasons in western Kenya, we treated the same cohort of young males to eradicate P. falciparum and then obtained blood smears each week for 4 months. We determined pubertal development by Tanner staging and by levels of dehydroepiandrosterone sulfate (DHEAS) and testosterone in plasma. In multivariate and age-stratified analyses, we examined the effect of pubertal development on resistance to malaria. In both seasons (n = 248 and 144 volunteers, respectively), older males were less susceptible than younger males. Age-related decreases in the frequency and density of parasitemia were greatest during puberty (15- to 20-year-olds). DHEAS and testosterone were significant independent predictors of resistance to P. falciparum parasitemia, even after accounting for the effect of age. Fifteen- to 20-year-old males with high DHEAS levels had a 72% lower mean parasite density (P<0.01) than individuals with low DHEAS levels. Similarly, 21- to 35-year-old males with high DHEAS levels had a 92% lower mean parasite density (P<0.001) and 48% lower frequency of parasitemia (P<0.05) than individuals with low DHEAS levels. These data suggest that the long period needed to attain full immunity could be explained as a consequence of host development rather than as the requirement to recognize variant or poorly immunogenic parasite antigens.
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Affiliation(s)
- J D Kurtis
- U.S. Army Medical Research Unit-Kenya and Kenya Medical Research Institute, Kisumu, Kenya
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Yoneto T, Yoshimoto T, Wang CR, Takahama Y, Tsuji M, Waki S, Nariuchi H. Gamma interferon production is critical for protective immunity to infection with blood-stage Plasmodium berghei XAT but neither NO production nor NK cell activation is critical. Infect Immun 1999; 67:2349-56. [PMID: 10225894 PMCID: PMC115977 DOI: 10.1128/iai.67.5.2349-2356.1999] [Citation(s) in RCA: 65] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
We have examined the roles of gamma interferon (IFN-gamma), nitric oxide (NO), and natural killer (NK) cells in the host resistance to infection with the blood-stage malarial parasite Plasmodium berghei XAT, an irradiation-induced attenuated variant of the lethal strain P. berghei NK65. Although the infection with P. berghei XAT enhanced NK cell lytic activity of splenocytes, depletion of NK1.1(+) cells caused by the treatment of mice with anti-NK1.1 antibody affected neither parasitemia nor IFN-gamma production by their splenocytes. The P. berghei XAT infection induced a large amount of NO production by splenocytes during the first peak of parasitemia, while P. berghei NK65 infection induced a small amount. Unexpectedly, however, mice deficient in inducible nitric oxide synthase (iNOS-/-) cleared P. berghei XAT after two peaks of parasitemia were observed, as occurred for wild-type control mice. Although the infected iNOS-/- mouse splenocytes did not produce a detectable level of NO, they produced an amount of IFN-gamma comparable to that produced by wild-type control mouse splenocytes, and treatment of these mice with neutralizing anti-IFN-gamma antibody led to the progression of parasitemia and fatal outcome. CD4(-/-) mice infected with P. berghei XAT could not clear the parasite, and all these mice died with apparently reduced IFN-gamma production. Furthermore, treatment with carrageenan increased the susceptibility of mice to P. berghei XAT infection. These results suggest that neither NO production nor NK cell activation is critical for the resistance to P. berghei XAT infection and that IFN-gamma plays an important role in the elimination of malarial parasites, possibly by the enhancement of phagocytic activity of macrophages.
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Affiliation(s)
- T Yoneto
- Department of Allergology, Institute of Medical Science, The University of Tokyo, Tokyo 108-8639, Japan
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Ramasamy R. Molecular basis for evasion of host immunity and pathogenesis in malaria. BIOCHIMICA ET BIOPHYSICA ACTA 1998; 1406:10-27. [PMID: 9545516 DOI: 10.1016/s0925-4439(97)00078-1] [Citation(s) in RCA: 42] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
The article relates the ability of the malaria parasite Plasmodium falciparum to avoid a protective immune response, and to induce pathological changes, to the properties of specific parasite molecules. Cytoadherence and rosetting are important features of cerebral malaria and involve proteins located on the surface of the infected red blood cell. Proinflammatory cytokines, particularly tumour necrosis factor (TNF), play a role in protective immunity and in inducing pathology. Glycophosphatidyl inositol membrane anchors of parasite proteins possess insulin like activity and induce TNF synthesis. People subject to repeated infections in malaria endemic areas rarely develop complete or sterile immunity to malaria. They frequently carry small numbers of parasites in the blood, with little symptoms of the disease, illustrating a phenomenon termed semi-immunity. The basis for semi-immunity is incompletely understood. Malaria parasites are susceptible to several immunological effector mechanisms. The presence of extensive repetitive regions is a feature of many P. falciparum proteins. Available evidence suggests that the structural characteristics of the repeats and their location on the surface of parasite proteins promote immunogenicity. The repeats may help the parasite evade host immunity by (i) exhibiting sequence polymorphism, (ii) preventing the normal affinity and isotype maturation of an immune response, (iii) functioning possibly as B cell superantigens, (iv) generating predominantly thymus independent antibody responses, and (v) acting as a sink for binding protective antibodies. Sequence diversity in non-repetitive regions and antigenic variation in parasite molecules located on the surface of infected red blood cells also play a role in immune evasion. Some sequence homologies between parasite and human proteins may be due to molecular mimicry. Homologies in other instances can cause autoimmune responses. The immune evasion mechanisms of the parasite need to be considered in developing vaccines. Protective immunity and pathology may be delicately balanced in malaria.
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Affiliation(s)
- R Ramasamy
- Molecular Biology Laboratory, Institute of Fundamental Studies, Kandy, Sri Lanka.
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Abstract
Tumour Necrosis Factor (TNF) is produced at the initiation of malaria infections (pre-erythrocytic phase), as demonstrated by the release of bioactive TNF by peripheral blood mononuclear cells from individuals residing in endemic areas after stimulation with stage specific sporozoite antigens. During the erythrocytic phase, TNF production is greatly augmented by parasite antigens at the time of schizont rupture and merozoite release from infected erythrocytes. Some of the strongest inducers of TNF synthesis and release are malaria toxins, e.g. glycosylphosphatidylinositol moieties and malaria pigment. Because of TNF's well-known cytotoxic activity it was originally hypothesized that it alone was responsible for killing parasites directly or within host cells. Though earlier reports of the capability of serum containing TNF to kill plasmodia supported this idea, later experiments with recombinant TNF showed a lack of significant parasiticidal activity. Recent studies investigating related factors showed that they were involved with TNF in the control of infection. These factors included -ther cytokines, such as interleukin (IL)-1, IL-6, IL-12, interferon-gamma (IFN gamma) as well as nitric oxide intermediates (NOI) and reactive oxygen intermediates (ROI). This positioned TNF as a key regulator of the immune response against the malaria parasite. However, it must be noted that TNF and its associated factors are also responsible for the fever, aches and pains of acute illness, as well as the hypoglycemia, shock, bleeding and reversible coma of severe malaria seen in approximately 1 percent of individuals with malaria. Therein lies the rub; factors important in the control of malaria also appear to have detrimental properties. Research presented in this review characterizes TNF and associated cytokines' importance in the immune response to malaria.
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Affiliation(s)
- A L Richards
- U.S. Naval Medical Research Unit No. 2, U.S. Embassy Jakarta, AP 96520-8132, USA.
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Jaso-Friedmann L, Leary JH, Warren J, McGraw RA, Evans DL. Molecular characterization of a protozoan parasite target antigen recognized by nonspecific cytotoxic cells. Cell Immunol 1997; 176:93-102. [PMID: 9073381 DOI: 10.1006/cimm.1996.1063] [Citation(s) in RCA: 23] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
The target cell antigen(s) on tumor cells and on protozoan parasites recognized by NK and nonspecific cytotoxic cells (NCC) has not yet been specifically identified. NCC may be the teleost equivalent of NK cells and IL-2-activated NK cells. A ligand recognized by NCC has been identified. It is expressed on both protozoan parasites and mammalian tumor target cells. In the present study, a protozoan parasite antigen (NK target antigen/NKTag/p46) was purified from Tetrahymena pyriformis and the entire amino acid sequence was deduced from cDNA. Soluble and purified NKTag inhibited NCC lysis of human and mouse transformed target cells. Homology comparisons using Swissprot database revealed that NKTag is a novel protein. Molecular weight computation of the deduced sequence demonstrated that NKTag is a 48.17-kDa protein containing 422 amino acids with relatively high percentages of tyrosine and serine residues. Expression of NKTag on various mammalian tumor target cells, normal tissue, and T. pyriformis was determined using anti-multiple antigenic peptide (MAP) monoclonal antibody (mab) 22A12 [generated against an N-terminal 20-mer (aa 61-80) of p46]. This mab bound to tissue-cultured and tumor cells (YAC-1, IM-9, NC-37, MOLT-4, and U937) with low levels of binding to fish, mouse, and equine cells. Studies were also done to determine if purified and iodinated NKTag bound specifically to NCC. Binding was saturable and specific. These data provide evidence that NCC recognize a target cell ligand which is found on both protozoan and tumor cells. This may provide an explanation as to how NCC (including activated NK cells) recognize a vast array of targets in the absence of haplotype recognition and in spite of a diverse species of origin.
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Affiliation(s)
- L Jaso-Friedmann
- College of Veterinary Medicine, University of Georgia, Athens 30602, USA
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Scharton-Kersten TM, Sher A. Role of natural killer cells in innate resistance to protozoan infections. Curr Opin Immunol 1997; 9:44-51. [PMID: 9039777 DOI: 10.1016/s0952-7915(97)80157-4] [Citation(s) in RCA: 81] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
Natural killer cells are now recognized as major effectors of innate resistance to protozoan parasites. The principal mechanism by which they control the growth of these pathogens is indirect, involving cytokine production rather than cytolytic activity. Recent studies have identified a series of positive and negative signals provided by cytokines and cellular interactions which regulate protozoa-induced natural killer cell function.
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Affiliation(s)
- T M Scharton-Kersten
- Immunobiology Section, Laboratory of Parasitic Diseases, National Institute for Allergy and Infectious Diseases, 9000 Rockville Pike, Building 4, Room 126, Bethesda, MD 20892-0425, USA.
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