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Karunakaran I, Ritter M, Pfarr K, Klarmann-Schulz U, Debrah AY, Debrah LB, Katawa G, Wanji S, Specht S, Adjobimey T, Hübner MP, Hoerauf A. Filariasis research - from basic research to drug development and novel diagnostics, over a decade of research at the Institute for Medical Microbiology, Immunology and Parasitology, Bonn, Germany. FRONTIERS IN TROPICAL DISEASES 2023; 4:1126173. [PMID: 38655130 PMCID: PMC7615856 DOI: 10.3389/fitd.2023.1126173] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/26/2024] Open
Abstract
Filariae are vector borne parasitic nematodes, endemic in tropical and subtropical regions causing avoidable infections ranging from asymptomatic to stigmatizing and disfiguring disease. The filarial species that are the major focus of our institution's research are Onchocerca volvulus causing onchocerciasis (river blindness), Wuchereria bancrofti and Brugia spp. causing lymphatic filariasis (elephantiasis), Loa loa causing loiasis (African eye worm), and Mansonella spp causing mansonellosis. This paper aims to showcase the contribution of our institution and our collaborating partners to filarial research and covers decades of long research spanning basic research using the Litomosoides sigmodontis animal model to development of drugs and novel diagnostics. Research with the L. sigmodontis model has been extensively useful in elucidating protective immune responses against filariae as well as in identifying the mechanisms of filarial immunomodulation during metabolic, autoimmune and infectious diseases. The institute for Medical Microbiology, Immunology and Parasitology (IMMIP), University Hospital Bonn (UKB), Bonn, Germany has also been actively involved in translational research in contributing to the identification of new drug targets and pre-clinical drug research with successful and ongoing partnership with sub-Saharan Africa, mainly Ghana (the Kumasi Centre for Collaborative Research (KCCR)), Cameroon (University of Buea (UB)) and Togo (Laboratoire de Microbiologie et de Contrôle de Qualité des Denrées Alimentaires (LAMICODA)), Asia and industry partners. Further, in the direction of developing novel diagnostics that are sensitive, time, and labour saving, we have developed sensitive qPCRs as well as LAMP assays and are currently working on artificial intelligence based histology analysis for onchocerciasis. The article also highlights our ongoing research and the need for novel animal models and new drug targets.
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Affiliation(s)
- Indulekha Karunakaran
- Institute for Medical Microbiology, Immunology and Parasitology (IMMIP), University Hospital Bonn (UKB), Bonn, Germany
| | - Manuel Ritter
- Institute for Medical Microbiology, Immunology and Parasitology (IMMIP), University Hospital Bonn (UKB), Bonn, Germany
| | - Kenneth Pfarr
- Institute for Medical Microbiology, Immunology and Parasitology (IMMIP), University Hospital Bonn (UKB), Bonn, Germany
- German Center for Infection Research (DZIF), partner site Bonn-Cologne, Bonn, Germany
| | - Ute Klarmann-Schulz
- Institute for Medical Microbiology, Immunology and Parasitology (IMMIP), University Hospital Bonn (UKB), Bonn, Germany
- German Center for Infection Research (DZIF), partner site Bonn-Cologne, Bonn, Germany
| | - Alexander Yaw Debrah
- Faculty of Allied Health Sciences, Kwame Nkrumah University of Science and Technology, Kumasi, Ghana
- Kumasi Center for Collaborative Research (KCCR), Kumasi, Ghana
| | - Linda Batsa Debrah
- Kumasi Center for Collaborative Research (KCCR), Kumasi, Ghana
- Department of Clinical Microbiology, School of Medicine and Dentistry, Kwame Nkrumah University of Science and Technology (KNUST), Kumasi, Ghana
| | - Gnatoulma Katawa
- Unité de Recherche en Immunologie et Immunomodulation (UR2IM)/Laboratoire de Microbiologie et de Contrôle de Qualité des Denrées Alimentaires (LAMICODA), Ecole Supérieure des Techniques Biologiques et Alimentaires, Université de Lomé, Lomé, Togo
| | - Samuel Wanji
- Parasites and Vector Research Unit (PAVRU), Department of Microbiology and Parasitology, University of Buea, Buea, Cameroon
- Research Foundation in Tropical Diseases and Environment (REFOTDE), Buea, Cameroon
| | - Sabine Specht
- Drugs for Neglected Diseases initiative, Geneva, Switzerland
| | - Tomabu Adjobimey
- Institute for Medical Microbiology, Immunology and Parasitology (IMMIP), University Hospital Bonn (UKB), Bonn, Germany
| | - Marc P Hübner
- Institute for Medical Microbiology, Immunology and Parasitology (IMMIP), University Hospital Bonn (UKB), Bonn, Germany
- German Center for Infection Research (DZIF), partner site Bonn-Cologne, Bonn, Germany
| | - Achim Hoerauf
- Institute for Medical Microbiology, Immunology and Parasitology (IMMIP), University Hospital Bonn (UKB), Bonn, Germany
- German Center for Infection Research (DZIF), partner site Bonn-Cologne, Bonn, Germany
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Tamadaho RSE, Ritter M, Wiszniewsky A, Arndts K, Mack M, Hoerauf A, Layland LE. Infection-Derived Monocytic MDSCs Require TGF-β to Suppress Filarial-Specific IFN-γ But Not IL-13 Release by Filarial-Specific CD4+ T Cells In Vitro. FRONTIERS IN TROPICAL DISEASES 2022. [DOI: 10.3389/fitd.2021.707100] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Lymphatic filariasis (LF) remains a major health problem with severe economic repercussions in endemic communities of Sub-saharan Africa, South-East Asia and South America. The rodent-specific nematode Litomosoides sigmodontis (Ls) is used to study the immunomodulatory potential of filariae and research has elucidated pathways involving regulatory T cells (Tregs), IL-10 producing cells and alternatively activated macrophages (AAMs) and that CD4+ T cells play a paramount role during infection. Myeloid-derived suppressor cells (MDSCs) have been identified and characterised in man in cancer and other pathologies. The hallmark of MDSC populations is the suppression of T and B cell responses using various mechanisms, which are mostly specific to the pathology or setting. However, until now, it remains unclear whether they play a role in filarial-specific responses. We report here that monocytic MDSCs (Mo-MDSCs, CD11b+Ly6C+Ly6G-) and polymorphonuclear MDSCs (PMN-MDSCs, CD11b+Ly6Cint/loLy6G+) expanded in the thoracic cavity (TC, the site of infection) and correlated positively with filarial life-stages in Ls-infected BALB/c mice. In vitro, only infection-derived Mo-MDSCs showed a suppressive nature by preventing IL-13 and IFN-γ secretion from filarial-specific CD4+ T cells upon co-culture with soluble worm extract. This suppression was not mediated by IL-10, IL-6 or TNF-α, and did not require cell-contact, nitric oxide (NO), IL-4/IL-5 signalling pathways or CCR2. Interestingly, neutralizing TGF-β significantly rescued IFN-γ but not IL-13 production by filarial-specific CD4+ T cells. In comparison to naive cells, PCR array data showed an overall down-regulation of inflammatory pathways in both infection-derived Mo-MDSCs and PMN-MDSCs. In conclusion, these primary data sets show activity and expansion of MDSCs during Ls infection adding this regulatory cell type to the complex milieu of host responses during chronic helminth infections.
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Risch F, Ritter M, Hoerauf A, Hübner MP. Human filariasis-contributions of the Litomosoides sigmodontis and Acanthocheilonema viteae animal model. Parasitol Res 2021; 120:4125-4143. [PMID: 33547508 PMCID: PMC8599372 DOI: 10.1007/s00436-020-07026-2] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2020] [Accepted: 12/20/2020] [Indexed: 12/16/2022]
Abstract
Filariae are vector-borne parasitic nematodes that are endemic worldwide, in tropical and subtropical regions. Important human filariae spp. include Onchocerca volvulus, Wuchereria bancrofti and Brugia spp., and Loa loa and Mansonella spp. causing onchocerciasis (river blindness), lymphatic filariasis (lymphedema and hydrocele), loiasis (eye worm), and mansonelliasis, respectively. It is estimated that over 1 billion individuals live in endemic regions where filarial diseases are a public health concern contributing to significant disability adjusted life years (DALYs). Thus, efforts to control and eliminate filarial diseases were already launched by the WHO in the 1970s, especially against lymphatic filariasis and onchocerciasis, and are mainly based on mass drug administration (MDA) of microfilaricidal drugs (ivermectin, diethylcarbamazine, albendazole) to filarial endemic areas accompanied with vector control strategies with the goal to reduce the transmission. With the United Nations Sustainable Development Goals (SDGs), it was decided to eliminate transmission of onchocerciasis and stop lymphatic filariasis as a public health problem by 2030. It was also requested that novel drugs and treatment strategies be developed. Mouse models provide an important platform for anti-filarial drug research in a preclinical setting. This review presents an overview about the Litomosoides sigmodontis and Acanthocheilonema viteae filarial mouse models and their role in immunological research as well as preclinical studies about novel anti-filarial drugs and treatment strategies.
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Affiliation(s)
- Frederic Risch
- Institute for Medical Microbiology, Immunology and Parasitology (IMMIP), University Hospital Bonn, Bonn, Germany
| | - Manuel Ritter
- Institute for Medical Microbiology, Immunology and Parasitology (IMMIP), University Hospital Bonn, Bonn, Germany
| | - Achim Hoerauf
- Institute for Medical Microbiology, Immunology and Parasitology (IMMIP), University Hospital Bonn, Bonn, Germany
- German Center for Infection Research (DZIF), partner site Bonn-Cologne, Bonn, Germany
| | - Marc P Hübner
- Institute for Medical Microbiology, Immunology and Parasitology (IMMIP), University Hospital Bonn, Bonn, Germany.
- German Center for Infection Research (DZIF), partner site Bonn-Cologne, Bonn, Germany.
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Finlay CM, Allen JE. The immune response of inbred laboratory mice to Litomosoides sigmodontis: A route to discovery in myeloid cell biology. Parasite Immunol 2020; 42:e12708. [PMID: 32145033 PMCID: PMC7317388 DOI: 10.1111/pim.12708] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2019] [Revised: 02/12/2020] [Accepted: 02/24/2020] [Indexed: 12/11/2022]
Abstract
Litomosoides sigmodontis is the only filarial nematode where the full life cycle, from larval delivery to the skin through to circulating microfilaria, can be completed in immunocompetent laboratory mice. It is thus an invaluable tool for the study of filariasis. It has been used for the study of novel anti‐helminthic therapeutics, the development of vaccines against filariasis, the development of immunomodulatory drugs for the treatment of inflammatory disease and the study of basic immune responses to filarial nematodes. This review will focus on the latter and aims to summarize how the L sigmodontis model has advanced our basic understanding of immune responses to helminths, led to major discoveries in macrophage biology and provided new insights into the immunological functions of the pleural cavity. Finally, and most importantly L sigmodontis represents a suitable platform to study how host genotype affects immune responses, with the potential for further discovery in myeloid cell biology and beyond.
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Affiliation(s)
- Conor M Finlay
- Lydia Becker Institute for Immunology & Infection, Faculty of Biology, Medicine & Health, Manchester Academic Health Science Centre, University of Manchester, Manchester, UK
| | - Judith E Allen
- Lydia Becker Institute for Immunology & Infection, Faculty of Biology, Medicine & Health, Manchester Academic Health Science Centre, University of Manchester, Manchester, UK
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The central adaptor molecule TRIF influences L. sigmodontis worm development. Parasitol Res 2019; 118:539-549. [PMID: 30643971 DOI: 10.1007/s00436-018-6159-1] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2018] [Accepted: 11/14/2018] [Indexed: 12/22/2022]
Abstract
Worldwide approximately 68 million people are infected with lymphatic filariasis (Lf), provoked by Wuchereria bancrofti, Brugia malayi and Brugia timori. This disease can lead to massive swelling of the limbs (elephantiasis) and disfigurement of the male genitalia (hydrocele). Filarial induced immune regulation is characterised by dominant type 2 helper T cell and regulatory immune responses. In vitro studies have provided evidence that signalling via Toll-like receptor-mediated pathways is triggered by filarial associated factors. Nevertheless, until now, less is known about the role of the adapter molecule TRIF during in vivo infections. Here, we used the rodent-specific nematode Litomosoides sigmodontis to investigate the role of TLR signalling and the corresponding downstream adapter and regulatory molecules TRIF, MyD88, IRF1 and IRF3 during an ongoing infection in semi-susceptible C57BL/6 mice. Interestingly, lack of the central adapter molecule TRIF led to higher worm burden and reduced overall absolute cell numbers in the thoracic cavity (the site of infection) 30 days post-infection. In addition, frequencies of macrophages and lymphocytes in the TC were increased in infected TRIF-/- C57BL/6 mice, whereas frequencies of eosinophils, CD4+ and CD8+ T cells were reduced. Nevertheless, cytokine levels and regulatory T cell populations remained comparable between TRIF-deficient and wildtype C57BL/6 mice upon 30 days of L. sigmodontis infection. In summary, this study revealed a crucial role of the adapter molecule TRIF on worm recovery and immune cell recruitment into the site of infection 30 days upon L. sigmodontis infection in C57BL/6 mice.
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Absence of IL-17A in Litomosoides sigmodontis-infected mice influences worm development and drives elevated filarial-specific IFN-γ. Parasitol Res 2018; 117:2665-2675. [PMID: 29931394 PMCID: PMC6061040 DOI: 10.1007/s00436-018-5959-7] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2017] [Accepted: 06/05/2018] [Indexed: 01/12/2023]
Abstract
Lymphatic filariasis, onchocerciasis and loiasis are widespread neglected tropical diseases causing serious public health problems and impacting the socio-economic climate in endemic communities. More than 100 million people currently suffer from filarial infections but disease-related symptoms and infection-induced immune mechanisms are still ambiguous. Although most infected individuals have dominant Th2 and regulatory immune responses leading to a homeostatic regulated state, filarial-induced overt pathology like lymphedema, dermal pathologies or blindness can occur. Interestingly, besides dominant Th2 and regulatory T cell activation, increased Th17-induced immune responses were associated with filarial infection and overt helminth-induced pathology in humans. However, the immunological mechanisms of Th17 cells and the release of IL-17A during filarial infections remain unclear. To decipher the role of IL-17A during filarial infection, we naturally infected IL-17A-/- and wildtype C57BL/6 mice with the rodent filariae Litomosoides sigmodontis and analysed parasite development and immune alterations. Our study reveals that infected IL-17A-deficient C57BL/6 mice present reduced worm burden on days 7 and 28 p.i. but had longer adult worms on day 28 p.i. in the thoracic cavity (TC), the site of infection. In addition, infiltration of CD4+ T cells, CD4+Foxp3+ regulatory T and functional CD4+Rorγt+pStat3+ Th17 cells in the TC was reduced in IL-17A-deficient mice accompanied by reduced eotaxin-1 and CCL17 levels. Furthermore, mediastinal lymph node cells isolated from IL-17A-/- mice showed increased filarial-specific IFN-γ but not IL-4, IL-6, or IL-21 secretion. This study shows that Th17 signalling is important for host immune responses against filarial infection but appears to facilitate worm growth in those that reach the TC.
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Ritter M, Tamadaho RS, Feid J, Vogel W, Wiszniewsky K, Perner S, Hoerauf A, Layland LE. IL-4/5 signalling plays an important role during Litomosoides sigmodontis infection, influencing both immune system regulation and tissue pathology in the thoracic cavity. Int J Parasitol 2017; 47:951-960. [PMID: 28859850 DOI: 10.1016/j.ijpara.2017.06.009] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2017] [Revised: 06/22/2017] [Accepted: 06/25/2017] [Indexed: 12/15/2022]
Abstract
Approximately 100 million people suffer from filarial diseases including lymphatic filariasis (elephantiasis), onchocerciasis (river blindness) and loiasis. These diseases are amongst the most devastating of the neglected tropical diseases in terms of social and economic impact. Moreover, many infection-induced immune mechanisms in the host, their relationship to disease-related symptoms and the development of pathology within the site of infection remain unclear. To improve on current drug therapies or vaccines, further studies are necessary to decipher the mechanisms behind filaria-driven immune responses and pathology development, and thus the rodent model of Litomosoides sigmodontis can be used to unravel host-filaria interactions. Interestingly, BALB/c mice develop a patent state (release of microfilariae, the transmission life-stage, into the periphery) when exposed to L. sigmodontis. Thus, using this model, we determined levels of host inflammation and pathology development during a L. sigmodontis infection in vivo for the first known time. Our study reveals that after 30days p.i., inflammation and pathology began to develop in infected wild type BALB/c mice between the lung and diaphragm, close to the site of infection - the thoracic cavity. Interestingly, infected IL-4Rα/IL-5-/- BALB/c mice had accentuated inflammation of the pleural lung and pleural diaphragm, and higher parasite burdens. Corresponding to the pleural inflammation, levels of IP-10, MIP-1α, MIP-1β, MIP-2 and RANTES were significantly elevated in the thoracic cavity fluid of infected IL-4Rα/IL-5-/- mice compared with wild type controls. Moreover, upon L. sigmodontis antigen stimulation, IFN-γ and IL-17A secretions by cells isolated from draining lymph nodes of IL-4Rα/IL-5-/- mice were significantly elevated, whereas secretion of IL-5, IL-13 and IL-10 was reduced. Elevated filaria-specific IFN-γ secretion was also observed in spleen-derived CD4+ T cell co-cultures from IL-4Rα/IL-5-/- mice. In summary, this study unravels the essential role of IL-4/IL-5 signalling in controlling immunity against filarial infections and demonstrates the requirement of this pathway for the host to control ensuing pathology and inflammation.
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Affiliation(s)
- Manuel Ritter
- Institute of Medical Microbiology, Immunology and Parasitology (IMMIP), University Hospital of Bonn, Germany
| | - Ruth S Tamadaho
- Institute of Medical Microbiology, Immunology and Parasitology (IMMIP), University Hospital of Bonn, Germany
| | - Judith Feid
- Institute of Medical Microbiology, Immunology and Parasitology (IMMIP), University Hospital of Bonn, Germany; German Centre for Infection Research (DZIF), Partner Site, Bonn-Cologne, Bonn, Germany
| | - Wenzel Vogel
- Pathology of the University Medical Center Schleswig-Holstein, Campus Luebeck and Research Center Borstel, Leibniz Center for Medicine and Biosciences, Luebeck and Borstel, Germany
| | - Katharina Wiszniewsky
- Institute of Medical Microbiology, Immunology and Parasitology (IMMIP), University Hospital of Bonn, Germany
| | - Sven Perner
- Pathology of the University Medical Center Schleswig-Holstein, Campus Luebeck and Research Center Borstel, Leibniz Center for Medicine and Biosciences, Luebeck and Borstel, Germany
| | - Achim Hoerauf
- Institute of Medical Microbiology, Immunology and Parasitology (IMMIP), University Hospital of Bonn, Germany; German Centre for Infection Research (DZIF), Partner Site, Bonn-Cologne, Bonn, Germany
| | - Laura E Layland
- Institute of Medical Microbiology, Immunology and Parasitology (IMMIP), University Hospital of Bonn, Germany; German Centre for Infection Research (DZIF), Partner Site, Bonn-Cologne, Bonn, Germany.
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