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Bjørgen H, Barac F, Fjelldal PG, Hansen T, Hordvik I, Koppang EO. Organisation of the Atlantic salmon (Salmo salar) thymus and its content of Ig-expressing cells. FISH & SHELLFISH IMMUNOLOGY 2024; 150:109652. [PMID: 38788913 DOI: 10.1016/j.fsi.2024.109652] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/22/2023] [Revised: 05/21/2024] [Accepted: 05/22/2024] [Indexed: 05/26/2024]
Abstract
The thymus of fishes is located as a dual organ in a rostrodorsal projection within the gill chamber and is covered by the operculum. The histological organization of the teleost fish thymus displays considerable diversity, particularly in salmonids where a clear distinction between the thymus cortex and medulla is yet to be defined. Recent interest has focused on the role of B cells in thymic function, but the presence of these cells within the salmon thymus remains poorly understood. In this morphological study, we applied in situ hybridization to investigate developing Atlantic salmon thymi for the expression of recombination activating (Rag) genes 1 and 2. We identified the location of the cortex, aligning with the previously described inner zone. Expression of IgM and IgD transcripts was predominantly observed in cells within the outer and subcapsular zones, with lesser expression in the cortex and inner zone. IgT expression was confined to a limited number of cells in the inner zone and capsule. The location of the thymus medulla could not be established. Our results are discussed in the context of the recently identified lymphoid organs, namely the intrabranchial lymphoid tissue (ILT) and the salmon bursa.
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Affiliation(s)
- Håvard Bjørgen
- Unit of Anatomy, Faculty of Veterinary Medicine, Norwegian University of Life Sciences, Oslo, Norway
| | - Fran Barac
- Unit of Anatomy, Faculty of Veterinary Medicine, Norwegian University of Life Sciences, Oslo, Norway
| | - Per G Fjelldal
- Matre Research Station, Institute of Marine Research, Matre, Norway
| | - Tom Hansen
- Matre Research Station, Institute of Marine Research, Matre, Norway
| | - Ivar Hordvik
- Institute of Biology, University of Bergen, Bergen, Norway
| | - Erling O Koppang
- Unit of Anatomy, Faculty of Veterinary Medicine, Norwegian University of Life Sciences, Oslo, Norway.
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2
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Sun B, Vindas MA, Kavaliauskiene S, Bjørgen H, Koppang EO, Wisløff H, Frisk M, Lund H, Johansen IB. Persistent immune responses in the heart determine the outcome of cardiomyopathy syndrome in Atlantic salmon (Salmo salar). FISH & SHELLFISH IMMUNOLOGY 2024; 147:109404. [PMID: 38325590 DOI: 10.1016/j.fsi.2024.109404] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/06/2023] [Revised: 01/18/2024] [Accepted: 01/23/2024] [Indexed: 02/09/2024]
Abstract
Cardiomyopathy syndrome (CMS) caused by piscine myocarditis virus (PMCV) is a severe cardiac disease in Atlantic salmon (Salmo salar) and one of the leading causes of morbidity and mortality in the Norwegian aquaculture industry. Previous research suggest a variation in individual susceptibility to develop severe disease, however the role of the immune response in determining individual outcome of CMS is poorly understood particularly in cases where fish are also challenged by stress. The present study's aim was therefore to characterize cardiac transcriptional responses to PMCV infection in Atlantic salmon responding to infection under stressful conditions with a high versus low degree of histopathological damage. The study was performed as a large-scale controlled experiment of Atlantic salmon smolts from pre-challenge to 12 weeks post infection (wpi) with PMCV, during which fish were exposed to intermittent stressors. RNA sequencing (RNAseq) was used to compare the heart transcriptome of high responders (HR) with atrium histopathology score '4' and low responders (LR) with score '0.5' at 12 wpi. A high-throughput quantitative PCR (qPCR) analysis was used to compare immune gene transcription between individuals sampled at 6, 9 and 12 wpi. Based on RNAseq and qPCR results, RNAscope in situ hybridization (ISH) was performed for visualization of IFN-γ - and IFNb producing immune cells in affected heart tissue. Compared to LR, the transcription of 1592 genes was increased in HR at 12 wpi. Of these genes, around. 40 % were immune-related, including various chemokines, key antiviral response molecules, and genes. associated with a Th1 pro-inflammatory immune response. Further, the qPCR analysis confirmed. increased immune gene transcription in HR at both 9 and 12 wpi, despite a decrease in PMCV. transcription between these time points. Interestingly, increased IFNb transcription in HR suggests the. presence of high-quantity IFN secreting cells in the hearts of these individuals. Indeed, RNAscope. confirmed the presence of IFN-γ and IFNb-positive cells in the heart ventricle of HR but not LR. To conclude, our data indicate that in severe outcomes of PMCV infection various chemokines attract leucocytes to the salmon heart, including IFN-γ and IFNb-secreting cells, and that these cells play important roles in maintaining persistent antiviral responses and a sustained host immunopathology despite decreasing heart viral transcription.
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Affiliation(s)
- Baojian Sun
- Faculty of Veterinary Medicine, Norwegian University of Life Sciences, Ås, Norway
| | - Marco A Vindas
- Faculty of Veterinary Medicine, Norwegian University of Life Sciences, Ås, Norway
| | | | - Håvard Bjørgen
- Faculty of Veterinary Medicine, Norwegian University of Life Sciences, Ås, Norway
| | - Erling Olaf Koppang
- Faculty of Veterinary Medicine, Norwegian University of Life Sciences, Ås, Norway
| | | | - Michael Frisk
- Institute for Experimental Medical Research, University of Oslo, Oslo, Norway
| | - Hege Lund
- Faculty of Veterinary Medicine, Norwegian University of Life Sciences, Ås, Norway
| | - Ida B Johansen
- Faculty of Veterinary Medicine, Norwegian University of Life Sciences, Ås, Norway.
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3
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Advances in chemokines of teleost fish species. AQUACULTURE AND FISHERIES 2023. [DOI: 10.1016/j.aaf.2023.01.008] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
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4
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Zapata AG. Lympho-Hematopoietic Microenvironments and Fish Immune System. BIOLOGY 2022; 11:747. [PMID: 35625475 PMCID: PMC9138301 DOI: 10.3390/biology11050747] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/09/2022] [Revised: 05/10/2022] [Accepted: 05/11/2022] [Indexed: 12/20/2022]
Abstract
In the last 50 years information on the fish immune system has increased importantly, particularly that on species of marked commercial interest (i.e., salmonids, cods, catfish, sea breams), that occupy a key position in the vertebrate phylogenetical tree (i.e., Agnatha, Chondrichtyes, lungfish) or represent consolidated experimental models, such as zebrafish or medaka. However, most obtained information was based on genetic sequence analysis with little or no information on the cellular basis of the immune responses. Although jawed fish contain a thymus and lympho-hematopoietic organs equivalents to mammalian bone marrow, few studies have accounted for the presumptive relationships between the organization of these cell microenvironments and the known immune capabilities of the fish immune system. In the current review, we analyze this topic providing information on: (1) The origins of T and B lymphopoiesis in Agnatha and jawed fish; (2) the remarkable organization of the thymus of teleost fish; (3) the occurrence of numerous, apparently unrelated organs housing lympho-hematopoietic progenitors and, presumably, B lymphopoiesis; (4) the existence of fish immunological memory in the absence of germinal centers.
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Affiliation(s)
- Agustín G. Zapata
- Department of Cell Biology, Faculty of Biology, Complutense University of Madrid, 28040 Madrid, Spain; ; Tel.: +34-913-944-979
- Health Research Institute, Hospital 12 de Octubre (imas12), 28041 Madrid, Spain
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5
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Liang C, Sheng X, Tang X, Xing J, Chi H, Zhan W. Structural characteristics and mucosal immune response of the interbranchial lymphoid tissue in the gills of flounder (Paralichthys olivaceus). FISH & SHELLFISH IMMUNOLOGY 2022; 123:388-398. [PMID: 35334297 DOI: 10.1016/j.fsi.2022.03.022] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/04/2022] [Revised: 03/15/2022] [Accepted: 03/17/2022] [Indexed: 06/14/2023]
Abstract
A specialized lymphoepithelial tissue termed the interbranchial lymphoid tissue (ILT) is recently identified in several fish species. However, the structural variation and mucosal immune functions of the ILT remain largely unknown. In this study, the anti-Zap-70 MAb was firstly determined to specifically recognize ZAP-70 protein, and CD4-1+, CD4-2+ and CD8β+ T-cells, but not IgM+ B cells, in peripheral blood leucocytes of flounder (Paralichthys olivaceus). Then we found that aggregates of Zap-70+ cells were located in the epithelium covering the bottom of the interbranchial cleft and along the afferent and efferent edges of the filaments in a cross view, where a meshwork of epithelial cells containing diffused lymphoid cells was exhibited, confirming these structures as the ILT; In a sagittal view, Zap-70+ cells were situated at the base of the filaments (here named as proximal ILT, pILT) and in the interlamellar epithelium (named as distal ILT, dILT). Also, a few IgM+ B cells were distributed at these sites. The lymphoepithelium within pILT and dILT was very thin with a low number of Zap-70+ cells in premetamorphosis and postclimax larvae of flounder, and got thicker containing much more Zap-70+ cells in juvenile and adult individuals. The aggregates of CD4-1+/Zap-70+, CD4-2+/Zap-70+, and CD8β+/Zap-70+ T-cell subsets were identified in the ILT. Post bath vaccination with inactivated Edwardsiella tarda and then intraperitoneal injection of EdU, the amounts of EdU+ and Zap-70+ cells obviously increased at 3 d and 7 d, and co-localization of EdU+/Zap-70+ cells identified the presence of proliferative T cells; meanwhile, MHC class II-expressing cells were increased. These findings indicated that the ILT in gills of flounder was an important site for the induction of local T cell-mediated immunity, which would lead to a better understanding of mucosal immunity and defense mechanisms of teleost fish.
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Affiliation(s)
- Chengcheng Liang
- Laboratory of Pathology and Immunology of Aquatic Animals, KLMME, Ocean University of China, 5 Yushan Road, Qingdao, 266003, PR China
| | - Xiuzhen Sheng
- Laboratory of Pathology and Immunology of Aquatic Animals, KLMME, Ocean University of China, 5 Yushan Road, Qingdao, 266003, PR China.
| | - Xiaoqian Tang
- Laboratory of Pathology and Immunology of Aquatic Animals, KLMME, Ocean University of China, 5 Yushan Road, Qingdao, 266003, PR China
| | - Jing Xing
- Laboratory of Pathology and Immunology of Aquatic Animals, KLMME, Ocean University of China, 5 Yushan Road, Qingdao, 266003, PR China
| | - Heng Chi
- Laboratory of Pathology and Immunology of Aquatic Animals, KLMME, Ocean University of China, 5 Yushan Road, Qingdao, 266003, PR China
| | - Wenbin Zhan
- Laboratory of Pathology and Immunology of Aquatic Animals, KLMME, Ocean University of China, 5 Yushan Road, Qingdao, 266003, PR China; Laboratory for Marine Fisheries Science and Food Production Processes, Qingdao National Laboratory for Marine Science and Technology, Qingdao, 266071, PR China
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6
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Aghaallaei N, Agarwal R, Benjaminsen J, Lust K, Bajoghli B, Wittbrodt J, Feijoo CG. Antigen-Presenting Cells and T Cells Interact in a Specific Area of the Intestinal Mucosa Defined by the Ccl25-Ccr9 Axis in Medaka. Front Immunol 2022; 13:812899. [PMID: 35185906 PMCID: PMC8853713 DOI: 10.3389/fimmu.2022.812899] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2021] [Accepted: 01/10/2022] [Indexed: 11/21/2022] Open
Abstract
Organized intestinal mucosal immune response appears to be restricted to tetrapods. In teleost fish, there is no evidence for the existence of a particular intestinal region that facilitates the interaction of antigen-presenting cells (APCs) and T cells, such as secondary lymphoid organs. Indeed, despite their importance in the defense against pathogens, the location and manner of APC-T cell interaction within the fish gut is unknown. Here, using non-invasive live imaging of newly developed transgenic reporter lines, we addressed the spatial organization and behavior of APCs and T cells in the intestine of medaka fish both during homeostasis and inflammation. We report that Ccr9a+ T cells are recruited to a band in the lamina propria next to the muscularis mucosa in which Ccl25-expressing cells are present. Ccr9a+ T cells contact APCs for several minutes, in a process mediated by connexin 43. This type of interaction was observed in homeostasis and inflammation, with the interaction being longer and more frequent during inflammation. Thus, our results demonstrate that the mucosal immune response in the intestine of medaka is organized and endowed with a specific region with specialized microenvironment and function.
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Affiliation(s)
- Narges Aghaallaei
- Centre for Organismal Studies (COS), Heidelberg University, Heidelberg, Germany
| | - Rashi Agarwal
- Centre for Organismal Studies (COS), Heidelberg University, Heidelberg, Germany
| | - Joergen Benjaminsen
- Centre for Organismal Studies (COS), Heidelberg University, Heidelberg, Germany
| | - Katharina Lust
- Centre for Organismal Studies (COS), Heidelberg University, Heidelberg, Germany
| | - Baubak Bajoghli
- Directors' Research Unit, European Molecular Biology Laboratory (EMBL), Heidelberg, Germany
| | - Joachim Wittbrodt
- Centre for Organismal Studies (COS), Heidelberg University, Heidelberg, Germany
| | - Carmen G Feijoo
- Centre for Organismal Studies (COS), Heidelberg University, Heidelberg, Germany.,Departamento de Ciencias Biologicas, Facultad de Ciencias de la Vida, Universidad Andres Bello, Santiago, Chile
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7
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Dalum AS, Kraus A, Khan S, Davydova E, Rigaudeau D, Bjørgen H, López-Porras A, Griffiths G, Wiegertjes GF, Koppang EO, Salinas I, Boudinot P, Rességuier J. High-Resolution, 3D Imaging of the Zebrafish Gill-Associated Lymphoid Tissue (GIALT) Reveals a Novel Lymphoid Structure, the Amphibranchial Lymphoid Tissue. Front Immunol 2021; 12:769901. [PMID: 34880866 PMCID: PMC8647647 DOI: 10.3389/fimmu.2021.769901] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2021] [Accepted: 10/25/2021] [Indexed: 12/24/2022] Open
Abstract
The zebrafish is extensively used as an animal model for human and fish diseases. However, our understanding of the structural organization of its immune system remains incomplete, especially the mucosa-associated lymphoid tissues (MALTs). Teleost MALTs are commonly perceived as diffuse and scattered populations of immune cells throughout the mucosa. Yet, structured MALTs have been recently discovered in Atlantic salmon (Salmo salar L.), including the interbranchial lymphoid tissue (ILT) in the gills. The existence of the ILT was only recently identified in zebrafish and other fish species, highlighting the need for in-depth characterizations of the gill-associated lymphoid tissue (GIALT) in teleosts. Here, using 3-D high-resolution microscopy, we analyze the GIALT of adult zebrafish with an immuno-histology approach that reveals the organization of lymphoid tissues via the labeling of T/NK cells with an antibody directed to a highly conserved epitope on the kinase ZAP70. We show that the GIALT in zebrafish is distributed over at least five distinct sub-regions, an organization found in all pairs of gill arches. The GIALT is diffuse in the pharyngeal part of the gill arch, the interbranchial septum and the filaments/lamellae, and structured in two sub-regions: the ILT, and a newly discovered lymphoid structure located along each side of the gill arch, which we named the Amphibranchial Lymphoid Tissue (ALT). Based on RAG2 expression, neither the ILT nor the ALT constitute additional thymi. The ALT shares several features with the ILT such as presence of abundant lymphoid cells and myeloid cells embedded in a network of reticulated epithelial cells. Further, the ILT and the ALT are also a site for T/NK cell proliferation. Both ILT and ALT show structural changes after infection with Spring Viraemia of Carp Virus (SVCV). Together, these data suggest that ALT and ILT play an active role in immune responses. Comparative studies show that whereas the ILT seems absent in most neoteleosts ("Percomorphs"), the ALT is widely present in cyprinids, salmonids and neoteleosts, suggesting that it constitutes a conserved tissue involved in the protection of teleosts via the gills.
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Affiliation(s)
- Alf S. Dalum
- Nofima, Norwegian Institute of Food, Fisheries and Aquaculture Research, Ås, Norway
| | - Aurora Kraus
- Center for Evolutionary and Theoretical Immunology (CETI), Department of Biology, University of New Mexico, Albuquerque, NM, United States
| | - Shanawaz Khan
- Department of Biosciences, FYSCELL, University of Oslo, Oslo, Norway
| | - Erna Davydova
- Department of Biosciences, BMB, University of Oslo, Oslo, Norway
| | | | - Håvard Bjørgen
- Section of Anatomy, Faculty of Veterinary Medicine, Norwegian University of Life Sciences, Ås, Norway
| | | | - Gareth Griffiths
- Department of Biosciences, FYSCELL, University of Oslo, Oslo, Norway
| | - Geert F. Wiegertjes
- Aquaculture and Fisheries Group, Department of Animal Sciences, Wageningen University & Research, Wageningen, Netherlands
| | - Erling O. Koppang
- Section of Anatomy, Faculty of Veterinary Medicine, Norwegian University of Life Sciences, Ås, Norway
| | - Irene Salinas
- Center for Evolutionary and Theoretical Immunology (CETI), Department of Biology, University of New Mexico, Albuquerque, NM, United States
| | - Pierre Boudinot
- INRAE, UVSQ, VIM, Université Paris-Saclay, Jouy-en-Josas, France
| | - Julien Rességuier
- Department of Biosciences, FYSCELL, University of Oslo, Oslo, Norway
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8
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Bjørgen H, Koppang EO. Anatomy of teleost fish immune structures and organs. Immunogenetics 2021; 73:53-63. [PMID: 33426583 PMCID: PMC7862538 DOI: 10.1007/s00251-020-01196-0] [Citation(s) in RCA: 67] [Impact Index Per Article: 22.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2020] [Accepted: 11/23/2020] [Indexed: 12/13/2022]
Abstract
The function of a tissue is determined by its construction and cellular composition. The action of different genes can thus only be understood properly when seen in the context of the environment in which they are expressed and function. We now experience a renaissance in morphological research in fish, not only because, surprisingly enough, large structures have remained un-described until recently, but also because improved methods for studying morphological characteristics in combination with expression analysis are at hand. In this review, we address anatomical features of teleost immune tissues. There are approximately 30,000 known teleost fish species and only a minor portion of them have been studied. We aim our review at the Atlantic salmon (Salmo salar) and other salmonids, but when applicable, we also present information from other species. Our focus is the anatomy of the kidney, thymus, spleen, the interbranchial lymphoid tissue (ILT), the newly discovered salmonid cloacal bursa and the naso-pharynx associated lymphoid tissue (NALT).
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Affiliation(s)
- Håvard Bjørgen
- Section of Anatomy, The Faculty of Veterinary Medicine, Norwegian University of Life Sciences, Ullevålsveien 72, Oslo, Norway
| | - Erling Olaf Koppang
- Section of Anatomy, The Faculty of Veterinary Medicine, Norwegian University of Life Sciences, Ullevålsveien 72, Oslo, Norway.
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9
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Barraza F, Montero R, Wong-Benito V, Valenzuela H, Godoy-Guzmán C, Guzmán F, Köllner B, Wang T, Secombes CJ, Maisey K, Imarai M. Revisiting the Teleost Thymus: Current Knowledge and Future Perspectives. BIOLOGY 2020; 10:biology10010008. [PMID: 33375568 PMCID: PMC7824517 DOI: 10.3390/biology10010008] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/02/2020] [Revised: 12/14/2020] [Accepted: 12/22/2020] [Indexed: 12/13/2022]
Abstract
Simple Summary The thymus is the immune organ producing T lymphocytes that are essential to create immunity after encountering pathogens or vaccination. This review summarizes the thymus localization and histological studies, cell composition, and function in teleost fishes. We also describe how seasonal changes, photoperiod, water temperature fluctuations, and hormones can affect thymus development in fish species. Overall, the information helps identify future studies needed to understand thymus function in fish species and the immune system’s evolutionary origins. Since fish are exposed to pathogens, especially under aquaculture conditions, knowledge about the fish thymus and T lymphocyte can also help improve fish farming protocols, considering intrinsic and environmental conditions that can contribute to achieving the best vaccine responsiveness for disease resistance. Abstract The thymus in vertebrates plays a critical role in producing functionally competent T-lymphocytes. Phylogenetically, the thymus emerges early during evolution in jawed cartilaginous fish, and it is usually a bilateral organ placed subcutaneously at the dorsal commissure of the operculum. In this review, we summarize the current understanding of the thymus localization, histology studies, cell composition, and function in teleost fishes. Furthermore, we consider environmental factors that affect thymus development, such as seasonal changes, photoperiod, water temperature fluctuations and hormones. Further analysis of the thymus cell distribution and function will help us understand how key stages for developing functional T cells occur in fish, and how thymus dynamics can be modulated by external factors like photoperiod. Overall, the information presented here helps identify the knowledge gaps and future steps needed for a better understanding of the immunobiology of fish thymus.
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Affiliation(s)
- Felipe Barraza
- Laboratory of Immunology, Center of Aquatic Biotechnology, Department of Biology, Faculty of Chemistry and Biology, University of Santiago of Chile, Av. Bernardo O’Higgins, Estación Central, Santiago 3363, Chile; (F.B.); (V.W.-B.); (H.V.)
| | - Ruth Montero
- Friedrich-Loeffler-Institute, Federal Research Institute for Animal Health, 17493 Greifswald, Insel Riems, Germany; (R.M.); (B.K.)
| | - Valentina Wong-Benito
- Laboratory of Immunology, Center of Aquatic Biotechnology, Department of Biology, Faculty of Chemistry and Biology, University of Santiago of Chile, Av. Bernardo O’Higgins, Estación Central, Santiago 3363, Chile; (F.B.); (V.W.-B.); (H.V.)
| | - Héctor Valenzuela
- Laboratory of Immunology, Center of Aquatic Biotechnology, Department of Biology, Faculty of Chemistry and Biology, University of Santiago of Chile, Av. Bernardo O’Higgins, Estación Central, Santiago 3363, Chile; (F.B.); (V.W.-B.); (H.V.)
| | - Carlos Godoy-Guzmán
- Center for Biomedical and Applied Research (CIBAP), School of Medicine, Faculty of Medical Sciences, Av. Bernardo O’Higgins, Estación Central, Santiago 3363, Chile;
| | - Fanny Guzmán
- Núcleo Biotecnología Curauma, Pontificia Universidad Católica de Valparaíso, Valparaíso 2373223, Chile;
| | - Bernd Köllner
- Friedrich-Loeffler-Institute, Federal Research Institute for Animal Health, 17493 Greifswald, Insel Riems, Germany; (R.M.); (B.K.)
| | - Tiehui Wang
- Scottish Fish Immunology Research Centre, School of Biological Sciences, University of Aberdeen, Aberdeen AB24 2TZ, UK; (T.W.); (C.J.S.)
| | - Christopher J. Secombes
- Scottish Fish Immunology Research Centre, School of Biological Sciences, University of Aberdeen, Aberdeen AB24 2TZ, UK; (T.W.); (C.J.S.)
| | - Kevin Maisey
- Laboratory of Comparative Immunology, Center of Aquatic Biotechnology, Department of Biology, Faculty of Chemistry and Biology, University of Santiago of Chile, Av. Bernardo O’Higgins, Estación Central, Santiago 3363, Chile;
| | - Mónica Imarai
- Laboratory of Immunology, Center of Aquatic Biotechnology, Department of Biology, Faculty of Chemistry and Biology, University of Santiago of Chile, Av. Bernardo O’Higgins, Estación Central, Santiago 3363, Chile; (F.B.); (V.W.-B.); (H.V.)
- Correspondence:
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10
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Lymphoid Tissue in Teleost Gills: Variations on a Theme. BIOLOGY 2020; 9:biology9060127. [PMID: 32549335 PMCID: PMC7344468 DOI: 10.3390/biology9060127] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/04/2020] [Revised: 06/07/2020] [Accepted: 06/12/2020] [Indexed: 11/16/2022]
Abstract
In bony fish, the gill filaments are essential for gas exchanges, but also are vulnerable to infection by water-borne microorganisms. Omnipresent across fish, gill-associated lymphoid tissues (GIALT) regulate interactions with local microbiota and halt infection by pathogens. A special GIALT structure has recently been found in Salmonids, the interbranchial lymphoid tissue (ILT). However, the structural variation of GIALT across bony fish remains largely unknown. Here, we show how this critical zone of interaction evolved across fishes. By labeling a conserved T-cell epitope on tissue sections, we find that several basal groups of teleosts possess typical ILT, while modern teleosts have lymphoepithelium of different shape and size at the base of primary gill filaments. Within Cypriniformes, neither body size variation between two related species, zebrafish and common carp, nor morphotype variation, did have a drastic effect on the structure of ILT. Thereby this study is the first to describe the presence of ILT in zebrafish. The ILT variability across fish orders seems to represent different evolutionary solutions to balancing trade-offs between multiple adaptations of jaws and pharyngeal region, and immune responses. Our data point to a wide structural variation in gill immunity between basal groups and modern teleosts.
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11
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Heimroth RD, Casadei E, Salinas I. Molecular Drivers of Lymphocyte Organization in Vertebrate Mucosal Surfaces: Revisiting the TNF Superfamily Hypothesis. JOURNAL OF IMMUNOLOGY (BALTIMORE, MD. : 1950) 2020; 204:2697-2711. [PMID: 32238457 PMCID: PMC7872792 DOI: 10.4049/jimmunol.1901059] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/30/2019] [Accepted: 02/26/2020] [Indexed: 12/19/2022]
Abstract
The adaptive immune system of all jawed vertebrates relies on the presence of B and T cell lymphocytes that aggregate in specific body sites to form primary and secondary lymphoid structures. Secondary lymphoid organs include organized MALT (O-MALT) such as the tonsils and Peyer patches. O-MALT became progressively organized during vertebrate evolution, and the TNF superfamily of genes has been identified as essential for the formation and maintenance of O-MALT and other secondary and tertiary lymphoid structures in mammals. Yet, the molecular drivers of O-MALT structures found in ectotherms and birds remain essentially unknown. In this study, we provide evidence that TNFSFs, such as lymphotoxins, are likely not a universal mechanism to maintain O-MALT structures in adulthood of teleost fish, sarcopterygian fish, or birds. Although a role for TNFSF2 (TNF-α) cannot be ruled out, transcriptomics suggest that maintenance of O-MALT in nonmammalian vertebrates relies on expression of diverse genes with shared biological functions in neuronal signaling. Importantly, we identify that expression of many genes with olfactory function is a unique feature of mammalian Peyer patches but not the O-MALT of birds or ectotherms. These results provide a new view of O-MALT evolution in vertebrates and indicate that different genes with shared biological functions may have driven the formation of these lymphoid structures by a process of convergent evolution.
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Affiliation(s)
- Ryan D Heimroth
- Center for Evolutionary and Theoretical Immunology, University of New Mexico, Albuquerque, NM 87131; and
- Department of Biology, University of New Mexico, Albuquerque, NM 87131
| | - Elisa Casadei
- Center for Evolutionary and Theoretical Immunology, University of New Mexico, Albuquerque, NM 87131; and
- Department of Biology, University of New Mexico, Albuquerque, NM 87131
| | - Irene Salinas
- Center for Evolutionary and Theoretical Immunology, University of New Mexico, Albuquerque, NM 87131; and
- Department of Biology, University of New Mexico, Albuquerque, NM 87131
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12
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Løken OM, Bjørgen H, Hordvik I, Koppang EO. A teleost structural analogue to the avian bursa of Fabricius. J Anat 2019; 236:798-808. [PMID: 31877586 PMCID: PMC7163591 DOI: 10.1111/joa.13147] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 12/03/2019] [Indexed: 01/26/2023] Open
Abstract
The bursa of Fabricius is a primary and secondary lymphoid organ considered exclusively present in birds, and studies of this structure have been vital to our current understanding of the adaptive immune system of vertebrates. In this study, we reveal substantial lymphoepithelial tissue in a previously undescribed bursa in Atlantic salmon (Salmo salar), situated caudal to the urogenital papilla of the cloaca and thus analogous to the anatomical placement of the bursa of Fabricius. We investigated three groups of Atlantic salmon at different maturational stages and characterized the structure by applying dissection, radiology, scanning electron microscopy and histological techniques, including immunohistochemistry and in situ hybridization. We found that the epithelial anlage of the salmon cloacal bursa developed into substantial lymphoepithelial tissue and subsequently regressed following sexual maturation. Such a dynamic development is also a key characteristic of the avian bursa. The presence of intraepithelial lymphocytes was concomitant with expression of the leukocyte-attracting chemokine CCL19, indicative of lymphoid organ functions. We did not observe recombination or gene conversion in salmon bursal lymphocytes at any developmental stage, indicating the absence of primary lymphoid organ functions in contrast to the bursa of Fabricius. However, the possibility of the bursa to trap both enteric and environmental antigens, combined with the presence of several antigen-presenting cells residing within the lymphoepithelium, suggest the structure has secondary lymphoid organ functions. We present the discovery of a lymphoid organ in Atlantic salmon with striking topographical similarities to that of the bursa of Fabricius in birds. In addition, the age-dependent dynamics of its lymphoepithelium suggest functions related to the maturation processes of lymphocytes.
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Affiliation(s)
- Oskar M Løken
- Section of Anatomy, Faculty of Veterinary Medicine, Norwegian University of Life Sciences, Oslo, Norway
| | - Håvard Bjørgen
- Section of Anatomy, Faculty of Veterinary Medicine, Norwegian University of Life Sciences, Oslo, Norway
| | - Ivar Hordvik
- Institute of Biology, University of Bergen, Bergen, Norway
| | - Erling O Koppang
- Section of Anatomy, Faculty of Veterinary Medicine, Norwegian University of Life Sciences, Oslo, Norway
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