Volkhard Kempf is Professor of Medical Microbiology and Infection Control at the Goethe University Frankfurt and Director of the Institute of Medical Microbiology and Infection Control at the University Hospital Frankfurt, Germany. After studying medicine at the Julius Maximilian University in Würzburg, Germany, and Oxford, Great Britain, he received his MD degree and medical approbation in 1997. He started his scientific career at the Max von Pettenkofer Institute of Ludwig Maximilian University in Munich, Germany, followed at the Eberhard Karls University in Tübingen, Germany, where he became Associate Professor in 2006. Since 2009 he is a full Professor and the head of the Department of Medical Microbiology and Infection Control at the Goethe University in Frankfurt. The focus of his research is the analysis of bacterial pathogenicity factors (bacterial adhesins) and the analysis of the human host cell response with special emphasis on hypoxia and cancer-related pathways. More recently, he became interested in the epidemiology of multidrug-resistant pathogens. Since 2001, he leads the National Consiliary Laboratory for Bartonella infections. He joined the Editorial Board of Medical Microbiology and Immunology as Editor-in-Chief for Bacteriology in 2012.
Matthias J. Reddehase is Professor of Virology and Director of the Institute for Virology at the University Medical Center and the Research Center for Immunotherapy of the Johannes Gutenberg-University in Mainz, Germany. After studying life sciences followed by training in basic cellular immunology at the German Cancer Research Center in Heidelberg, Germany, he switched to viral immunology with a doctoral thesis on Cytomegalovirus (CMV) pathogenesis and immune control, followed by postdoctoral training in the research team of Ulrich H. Koszinowski in Tübingen, Germany. After a period as a research group leader and senior lecturer at the Department of Virology of the Medical Faculty of the University of Ulm, Germany, he was appointed to full Professor at his present affiliation in 1994. His research is focused on the development of preclinical models of Cytomegalovirus (CMV) pathogenesis, immune evasion, latent infection and reactivation as well on T cell-based immunotherapy of CMV disease in the specific context of hematopoietic cell transplantation. After having already served as Guest Editor for Medical Microbiology and Immunology in the past, he joined the Editorial Board in 2018 as Editor-in-Chief for Virology.
Christian Bogdan is Professor of Medical Microbiology and Infectious Disease Immuology at the Friedrich Alexander-University (FAU) Erlangen-Nürnberg and Director of the Institute of Clinical Microbiology, Immunology and Hygiene at the University Hospital Erlangen, Germany. After studying medicine at FAU and the University College and Middlesex Hospital Medical School in London, UK, he received his MD degree and medical approbation in 1988. Following postdoctoral training at the Center for Molecular Biology in Heidelberg, Germany, and at Cornell University Medical College in New York, USA, he became Assistant and later on Associate Professor at FAU in Erlangen. From 2003 to 2007 he was full Professor and head of the Department of Microbiology at the Albert Ludwigs-University in Freiburg. His research focuses on various components of the innate immune system and the defense against intracellular pathogens, including macrophages, natural killer cells, type I interferons, tumor necrosis factor and inducible nitric oxide synthase. More recently, his group became also interested in the development of novel treatment strategies in cutaneous leishmaniasis. He joined the Editorial Board of Medical Microbiology and Immunology as Editor-in-Chief for Immunology in 2018.
Steven J. Ackerman is a Professor of Biochemistry and Molecular Genetics, and Professor of Medicine in the Departments of Biochemistry and Molecular Genetics, and Medicine at the University of Illinois at Chicago, Chicago, Illinois, United States. His research focuses on eosinophil immunobiology and functions in allergic diseases such as asthma and eosinophilic esophagitis, with a focus on their roles in tissue remodeling and fibrosis, the biochemistry, cell and structural biology of eosinophil protein mediators of inflammation, and transcriptional and epigenetic mechanisms regulating hematopoietic (eosinophil) development and gene expression in health and disease. His laboratory is developing a novel class of biased antagonists of GPCRs for treatment of allergic diseases, focusing on CCR3, the receptor for eotaxins involved in eosinophil activation and recruitment into tissues.
Volker Lohmann is Associate Professor at the Department Infectious Diseases, Molecular Virology in Heidelberg where he is heading the section “Virus-Host-Interactions”. His research focusses on the understanding of the replication mechanisms of positive strand RNA viruses, in particular Hepatitis C virus, Hepatitis A virus and noroviruses. He is mainly interested in the cell biology of viral infections, interactions with specific host factors, mode of action of antiviral therapies, induction and counteraction of innate immune responses and persistence and pathogenesis mechanisms of hepatotropic viruses.
Stephan Becker is Professor of Virology and Director of the Institute of Virology at the Philipps University Marburg, Germany. His research focuses on emerging viruses like Ebola virus, Marburg virus and MERS Coronavirus. He is interested in replication and pathogenesis of these viruses and in the development of emergency vaccines.
Sammy Bedoui is an Associate Professor at the Department of Microbiology and Immunology, University of Melbourne and the Peter Doherty Institute for Infection and Immunity, Melbourne, Australia.He is interested in how innate signals are integrated into adaptive immunity against infections. His research has defined how memory T cells protect the host from bacterial infections, uncovering that these responses are regulated through inflammasomes and other types of pattern recognition receptors within dendritic cells. His work on virus infections has identified how different dendritic cell types contribute to the initiation of virus-specific immunity and has delineated how specific viral fragments augment these responses. Ongoing work interrogates the mechanisms by which T cells ‘help’ dendritic cells in driving immune responses and how cues from the microbiome inform T cell immunity and metabolism.
Sindy Böttcher is a Research Associate and Deputy Head of the German National Reference Center for Poliomyelitis and Enteroviruses at the Robert Koch-Institute, Berlin, Germany. Her research focuses on the molecular epidemiology of enteroviruses and parechoviruses linking molecular virology and clinical presentation.
Dunja Bruder is Professor of Infection Immunology at the Otto-von-Guericke University (OvGU) Magdeburg and Head of the Immune Regulation Group at the Helmholtz Centre for Infection Research (HZI) in Braunschweig, Germany. Her research focuses on basic principles underlying pulmonary immune regulation during bacterial and viral infections with special emphasis on immunological functions of alveolar type II epithelial cells. Moreover, co-morbidities between communicable and non-communicable diseases as well as co-infections with influenza A virus and Streptococcus pneumonia are investigated.
Margarita Del Val is Senior Researcher at Centro de Biología Molecular Severo Ochoa, a joint institution of the CSIC, the Spanish National Research Council, and the Universidad Autónoma de Madrid, Spain. She studies adaptive immunity and how viral antigens are processed and presented by MHC molecules at the surface of professional antigen presenting cells and of infected cells, which determines the control of virus infections by CD8+ cytotoxic T lymphocytes. Together with studies on the molecular mechanisms of CD8+ T lymphocyte memory, her research ultimately aims at vaccine development.
Thomas Decker is Professor of Immunobiology at the Max F. Perutz Laboratories of the University of Vienna, Austria. His research area of expertise is immunity to infection. His special research interests are interferons, pathways regulating their synthesis, their role in inflammation and infection, Jak-Stat signal transduction by the interferon receptors, regulation of interferon-induced gene expression and cooperative activities of the interferon and NFkB pathways.
Albert Descoteaux is a Professor at the Centre Armand-Frappier of the Institut national de la recherche scientifique (Université du Québec, Canada) and holder of the Canada Research Chair on the Biology of intracellular parasitism. His research is focussed on interactions between the protozoan parasite Leishmania, and host macrophages. He his particularly interested in the biology of the Leishmania parasitophorous vacuole and in the immune evasion mechanism(s) used by this parasite.
Stefan Ehlers is Professor of Molecular Inflammation Medicine at the University of Kiel and Chief Executive Director of the Leibniz Lung Center in Borstel (Forschungszentrum Borstel), Germany. His research focuses on the virulence and persistence of mycobacteria, in particular M. tuberculosis. He studies the immunopathogenesis of granuloma formation and uses the mouse aerosol model for developing new antimicrobial strategies to combat tuberculosis. His interests include novel diagnostic and therapeutic tools to manage multi-drug resistant tuberculosis.
Sabine Ehrt is Professor of Microbiology and Immunology at Weill Cornell Medical College in New York, USA. Her research focuses on the pathogenesis of tuberculosis with special emphasis on the molecular mechanisms that Mycobacterium tuberculosis uses to establish and maintain chronic infections. Her group is also involved in the identification and validation of new tuberculosis drug targets.
John Fraser is a Professor in Immunology and Dean of the Faculty of Medical and Health Sciences, University of Auckland, New Zealand. His research focuses on the mechanisms of bacterial virulence and pathogenicity of S. aureus and S. pyogenes, and the innate and adaptive immune mechanisms that provide protective immunity.
Gülsah Gabriel is Professor for Viral Zoonoses at the University of Lübeck, Germany. Se is also Head of the Department Viral Zoonoses – One Health at the Heinrich Pette Institute, Leibniz Institute for Experimental Virology in Hamburg, Germany. Her major research interest is to understand influenza A virus interspecies transmission as well as pathogenesis in major risk groups. Since 2014, she is Vice-President of the European Working Group on Influenza.
Adrian Goldman is Chair of Membrane Biology at the University of Leeds, England. He has a joint appointment at the University of Helsinki, Finland and holds a Lecture Professor position at Nankai University in Tianjin, China.The focus of his research is on understanding protein structure and function at the cell surface, in particular membrane transporters and the interaction of bacterial proteins with the host immune system. One particular interest has been the mechanism of action of integral membrane pyrophosphatases in protozoan parasites and bacterial pathogens. He has recently started focussing on unique transporters in Mycobacterium. He joined the editorial board of Medical Microbiology and Immunology in 2018.
Deyin Guo is Professor of Virology and Dean of the School of Medicine at Sun Yat-sen University in Guangzhou and Shenzhen, PR China. He also serves as the President of the Virology Division of the Chinese Society for Microbiology. His research focuses on molecular mechanisms of the infection and pathogenesis of coronaviruses and flaviviruses, in particular on the RNA genome replication and immune regulation of viral infection. He is also interested in the gene editing-based genetic therapy of HIV/AIDS.
Georg Häcker is Director of the Institute of Medical Microbiology and Hygiene, University Medical Center Freiburg. His research focus is the molecular and cellular host cell response to bacterial infections. One main question is the role of the apoptosis apparatus in host response, and how bacteria deal with cell-autonomous host responses to the infection. A major effort is directed at understanding how the obligate intracellular bacterium Chlamydia trachomatis is able to establish itself in human epithelial cells, and how it is possible to interfere with this process therapeutically.
Petr Hubacek is a Professor at the Department of Clinical Microbiology, 2nd Faculty of Medicine, Charles University, and Department of Paediatric Haematology and Oncology, Motol University Hospital, Prague, Czech Republic.
Jonathan Jantsch is Professor of Bacteriology and Microbial Immunity at the Institute of Clinical Microbiology and Hygiene, University of Regensburg and University Hospital Regensburg, Germany. His research interests are tissue microenvironment in inflamed/ infected tissues and its impact on antimicrobial defense as well as innate microbial immunity. (Photo: ©UKR/ Ulla Lohse)
Stipan Jonjic is Professor and Chair at the Department of Histology and Embryology and the Center for Proteomics at the Faculty of Medicine, University of Rijeka, Croatia. The focus of his research is the immune response to cytomegalovirus (CMV) mediated by components of innate and acquired immunity. His group is most recognized for the characterization of numerous immunoevasion mechanisms encoded by CMV genes.
Ulrich Kalinke is Executive Director of TWINCORE, Centre for Experimental and Clinical Infection Research GmbH, Hannover, Director of the Institute for Experimental Infection Research at TWINCORE, and University Professor for Translational Infection Research at the Hannover Medical School. After studying biology at the Technical University Hannover he proceeded with experimental studies at the German Cancer Research Centre, Heidelberg and in 1990 he received his PhD from the University of Heidelberg. Following postdoctoral training in the research team of Rolf M. Zinkernagel and Hans Hengartner at the University Hospital Zürich, Switzerland, in 1998 he became Staff Scientist and Head of the “Anti-Viral Defense Group” at the European Molecular Biology Laboratory (EMBL), Mouse Biology Programme, Monterotondo (Rom), Italy. In 2002 he became Professor and Director of the Division of Immunology at the Paul-Ehrlich-Institut, Langen, Germany. Since 2008 he is holding his current position. His research aims at an improved understanding of how the host mounts early anti-viral immune responses and how these responses affect the overall disease outcome. Specifically, it is analyzed which cellular sensing platforms confer virus-sensing in different cell types and how antiviral interferon responses block virus dissemination. In addition to unraveling general principles of immune mechanisms, his group focuses on the analysis of processes underlying infection associated tissue inflammation, including hepatitis, pneumonia, myocarditis, and encephalitis. With regard to viral encephalitis the role of interferons in the crosstalk between neurons, astrocytes, and microglia is being analyzed. The research focuses on studies with herpesviruses including human and murine cytomegalovirus (HCMV and MCMV) and herpes simplex virus (HSV) as well as model viruses such as vesicular stomatitis virus (VSV).
Oliver T. Keppler is Professor of Virology and Head of Virology at the Max von Pettenkofer Institute, Faculty of Medicine, LMU München in Munich, Germany. The Institute also functions as National Reference Center for Retroviruses.His laboratory seeks to understand the pathological interplay of HIV with the host’s immune system and its target cells with the goal of providing new approaches for prophylaxis and therapy.
Jörg Köhl is Professor of Immunology at the Medical Section of the University of Lübeck and the Founding Director of the Institute for Systemic Inflammation Research, Germany. Further he is Adjunct Professor of Pediatrics in the Division of Immunobiology at Cincinnati Children's Hospital Medical Center and University of Cincinnati College of Medicine, Cincinnati, OH, USA.His research focuses on the biology of the complement system. A particular focus is on the multiple functions of the small cleavage fragments of C3 and C5, i.e. the anaphylatoxins and their cognate C3a and C5a receptors in the network of innate and adaptive immune responses. He has developed many tools to characterize the functions of the anaphylatoxins and their receptors including neo-epitope-specific C3a and C5a antibodies, a specific C5aR1/C5aR2 double inhibitor and floxed C3aR, C5aR1 and C5aR2 reporter mice. Currently, he serves as the spokesperson of the DFG International Research Training Group 1911 on the immunoregulation of inflammation in allergy and infection.
Manfred Kopf is Professor of Molecular Biomedicine at the Institute of Molecular Health Sciences, ETH Zürich, Switzerland, and chair of the ETH Phenomics Center (EPIC). His research focuses on inflammatory and infectious diseases in mouse models. He and his research group have been investigating the cellular and molecular mechanisms of innate and adaptive immune responses (i) in inflammatory diseases such as asthma, atherosclerosis, and psoriasis, and (ii) infectious diseases mediated by influenza virus, lymphocytic choriomeningitis virus, Leishmania major, and Listeria monocytogenes. Beyond that he has a long-term interest in defining the role of cytokines in development and disease.
Roland Lang is an Associate Professor at the Institute of Clinical Microbiology, Immunology and Hygiene at the University Hospital Erlangen, Germany. His main research interests are innate immune receptors and pathways of pathogen recognition, how innate immune activation is regulated by cytokines and modulators of intracellular signaling, and the implications of these interactions for inflammation, infection and during immunization.
Salomé LeibundGut-Landmann is Professor of Immunology at the University of Zürich, Switzerland, and Head of the Section of Immunolgy at the Vetsuisse Faculty of the same Institution. Her research focuses on host defense mechanisms to opportunistic human fungal pathogens such as Candida albicans with a special emphasis on type 17 immunity (Th17 cells, innate IL-17 producers) and neutrophils in mucosal barrier tissues and during systemic infections. More recently, her group became also interested in the interaction of the commensal yeast Malassezia with the cutaneous immune system and the contribution of this fungus to inflammatory skin disorders such as atopic dermatitis.
Thomas Lion is Professor of Laboratory Medicine and Tumor Genetics at the Medical University of Vienna (MUV), Head of Molecular Microbiology at the Children´s Cancer Research Institute (CCRI), Vienna, and Medical Director of the diagnostic center Labdia Labordiagnostik Vienna, Austria. In the field of infectious diseases, his research focuses on adenoviruses and other viral pathogens in the immunocompromised host, and on various aspects of invasive fungal infections. More recently, his group became also interested in bacterial-fungal interactions and in the role of the microbiome in pediatric patients with malignant disorders.
Peter J. Murray is Senior Group Leader of the Immunoregulation Group at the Max Planck Institute for Biochemistry, Martinsried, Germany. He focuses on immune regulation from multiple angles, and most recently on immune regulatory events mediated by metabolic crosstalk. He is probably best known for his work on macrophages, IL-10 and arginine metabolism in immunity. His current research is focusing on translating principles learned from infection biology to the cancer area, along with fundamental research into regulatory control points applicable to any type of immune response.
Bastian Opitz is Professor of Pulmonary Innate Immunity at the Department of Internal Medicine/Infectious Diseases and Pulmonary Medicine at the Charité Universitätsmedizin Berlin, Germany. His research focuses on lung infections and various aspects of the innate immune system, including pattern recognition receptors, interferons and interferon-stimulated antibacterial factors, macrophages, as well as epithelial cell-derived factors. More recently, his group became also interested in the microbiota - immune system crosstalk, how this crosstalk is affected by antimicrobial therapies and how it influences bacterial pneumonia. His long-time goal is the development of novel strategies for the prevention and treatment of bacterial pneumonia and particularly of infections with multidrug-resistant bacteria.
Stefan Rose-John is Professor of Biochemistry and Director of the Institute for Biochemistry at the University of Kiel Medical School in Kiel, Germany. His research is focused on the molecular biology of cytokines, in particular Interleukin-6. He has established the paradigm of Interleukin-6 trans-signaling via a soluble Interleukin-6 receptor, which enables cells, which do not express Interleukin-6 receptor, to respond to the cytokine. He has found that Interleukin-6 trans-signaling via the soluble Interleukin-6 receptor is mainly pro-inflammatory whereas Interleukin-6 signaling via the membrane bound Interleukin-6 receptor is rather protective and regenerative. Moreover, he has developed a specific inhibitor of Interleukin-6 trans-signaling, which does not interfere with classic Interleukin-6 signaling via the membrane bound Interleukin-6 receptor. This inhibitor, under the name Olamkicept is in phase II clinical trials for the treatment of autoimmune diseases.
Bernhard Ryffel is a Professor affiliated to CNRS Orleans, France, and the Universities of Cape Town, South Africa, and Sun Yat Sen, Guangzhou, PR China. His field of research are immunology and pulmonary inflammation/infection with expertise in Innate immune sensing of pathogens and danger signals, inflammasome activation, role of IL-1 and IL-1 family members especially IL-33, Th17 differentiation, ILCs and aryl hydrocarbon receptor, role of microbiota on tissue homeostasis and inflammation, nutrition, obesity and diabetes.
Dirk Schlüter is Professor of Medical Microbiology and Infectious Disease Immunology at the Otto-von-Guericke University (OVGU) Magdeburg and Director of the Institute of Medical Microbiology and Infection Control at the University Hospital Magdeburg, Germany. His research focuses on infection immunology with a particular emphasis on the function of cell surface receptors and the positive and negative regulation of associated signaling pathways (including ubiquitination and deubiquitination). His interests in Clinical Microbiology focus on Clostridium
Thomas F. Schulz is Professor of Virology and Director of the Institute of Virology at Hannover Medical School, Germany. His research is focused on Kaposi Sarcoma Herpesvirus (KSHV)/Human Herpesvirus 8 (HHV 8), the infectious cause of Kaposi Sarcoma, Primary Effusion Lymphoma and the plasma cell variant of Multicentric Castleman’s disease. Research topics pursued in his group include the regulation of viral latency, the role of the cellular DNA damage response in restricting viral infection, the molecular mechanisms underlying the virus-induced angiogenesis and the development of novel antivirals against KSHV. He is also Speaker of the DFG Collaborative Research Centre 900 on Chronic Infections.
Roberto F. Speck is Professor in the Division of Infectious Diseases and Hospital Epidemiology at the University Hospital of Zurich, Switzerland. The focus of his research is molecular virology, in particular HIV, the innate immune response with a major focus on the IFN system and the monocyte/macrophage lineage, and gene engineering. His laboratory has substantially contributed to the development and the acceptance of humanized mice for studying HIV.
Simona Stäger is an Associate Professor at the Institut National de la Recherche Scientifique- Institut Armand-Frappier in Laval, Canada. Her research focuses on the immunopathogenesis, immune evasion and regulation of adaptive immunity in the experimental model of visceral leishmaniasis. Her laboratory also uses viral models to investigate differentiation, maintenance and memory generation of T cells.
Steffen Stenger is Medical Director of the Institute for Medical Microbiology and Infection Control at the University Hospital in Ulm, Germany. The focus of his research is the human immune response in tuberculosis. The major interest is to identify and characterize endogenous peptides with antimicrobial activity against Mycobacterium tuberculosis.
Fabienne Tacchini-Cottier is Professor of Immunology at the Department of Biochemistry and Director of the World Health Organisation Immunology Research and Training collaborative Center, at the University of Lausanne, Switzerland. Her research focuses on the mechanisms involved in innate and adaptive immune response to intracellular pathogens, with a focus on cutaneous leishmaniasis. Her group has a special interest on the impact of neutrophils in the various forms of the disease and on the innate sensors driving a protective adaptive immune response. Recently, her group became interested in better understanding the mechanisms involved in resistance to the commonly available anti-leishmanial drugs.
Mauro Teixeira is Professor of Immunology at the Department of Biochemistry and Immunology and Head of the Center for Drug Research and Development, Universidade Federal de Minas Gerais, Brazil. His research focuses on studying the role of inflammation in host-microbial interaction and developing novel inflammation-based therapies to treat infections. Particular emphasis is given to the role inflammation in the context of viral infection, including influenza and arboviral infection, especially dengue, Zika and Chikungunya. Development of animal models is an important aspect of the work. His clinical interest is mostly related to infectious diseases of local relevance, in particular arboviral and protozoan infections.
Jordi Vila is Full Professor of the School of Medicine, University of Barcelona. Currently he is Head of the Department of Clinical Microbiology of the Hospital Clinic as well as Research Professor in the Institute for Global Health (ISGlobal) in Barcelona, Spain. His area of expertise is mainly antimicrobial resistance and his main field of interest is the development of new drugs against MDR bacteria and molecular tools for rapid diagnosis of infectious disease.
Sebastian Voigt is a pediatrist at the Department of Pediatric Oncology/Hematology/Stem Cell Transplantation of the Charité ‐ Universitätsmedizin Berlin, Germany, and is affiliated with the Department of Infectious Diseases of the Robert Koch Institute in Berlin, Germany. He focusses on infectious diseases in immunocompromised children and his laboratory also performs fundamental research related to cytomegalovirus and its interference with the host immune system.
Takaji Wakita is the Director-General of the National Institute of Infectious Diseases, Tokyo, Japan. His major research interests include infection and replication models of hepatitis B and C viruses, pathogenesis of hepatitis viruses as well as the development of novel therapeutics and vaccines for hepatitis virus infections.
Guenter Weiss is full Professor for Internal Medicine at the Medical University of Innsbruck, Austria, and Director of the Department of Internal Medicine II. His research interest focuses on host-pathogen interaction with a special emphasis on the role of innate immune cells, natural resistance genes and the metabolic environment for the control of infection with intra- and extracellular bacteria.
Silja Wessler is Professor for Microbiology at the Paris-Lodron University of Salzburg, Austria. Her research focuses on the cellular and molecular mechanisms of pathogen-host interactions, function of virulence factors, pathogen-induced signal transduction pathways and pathogenesis. In particular, she is interested in the biology of the bacterial class-I carcinogen Helicobacter pylori.
Muhammad Hamid Zaman is at Howard Hughes Medical Institute Professor of Biomedical Engineering and International Health at Boston University. Prof. Zaman’s current research is focused on understanding the link between poor quality medicines and antimicrobial resistance in low-income settings and conflict zones. His lab is working on understanding the molecular mechanisms of resistance due to poor quality drugs as well as developing new technologies to test and analyze drug quality in low-resource environments.
Ulrike Wieland is Professor of Virology and Deputy Medical Director at the Institute of Virology, University Hospital of Cologne, Germany. Her research interests include epidemiology, diagnostics, and treatment of human papillomavirus and of cutaneous polyomavirus infections. She also heads the National Reference Center for Papilloma- and Polyomaviruses.
Christina Zielinski is Professor of Immune Diagnostics of Infections of the German Center for Infection Research at the Institute of Virology and the Center for Translational Cancer Research (TranslaTUM), Technical University of Munich, Germany. Her research focusses on the mechanisms that control human T-cell fate decisions. Through a better understanding of the molecular switches that shape T cell identities, tissue tropism and longevity as well as the T-cell dialogue with the tissue microenvironment, she works towards strategies that will provide new diagnostic and therapeutic options for cancer, autoimmunity and chronic infections.