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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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Steinel NC, Bolnick DI. Melanomacrophage Centers As a Histological Indicator of Immune Function in Fish and Other Poikilotherms. Front Immunol 2017; 8:827. [PMID: 28769932 PMCID: PMC5512340 DOI: 10.3389/fimmu.2017.00827] [Citation(s) in RCA: 126] [Impact Index Per Article: 18.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2017] [Accepted: 06/30/2017] [Indexed: 12/14/2022] Open
Abstract
Melanomacrophage centers (MMCs) are aggregates of highly pigmented phagocytes found primarily in the head kidney and spleen, and occasionally the liver of many vertebrates. Preliminary histological analyses suggested that MMCs are structurally similar to the mammalian germinal center (GC), leading to the hypothesis that the MMC plays a role in the humoral adaptive immune response. For this reason, MMCs are frequently described in the literature as “primitive GCs” or the “evolutionary precursors” to the mammalian GC. However, we argue that this designation may be premature, having been pieced together from mainly descriptive studies in numerous distinct species. This review provides a comprehensive overview of the MMC literature, including a phylogenetic analysis of MMC distribution across vertebrate species. Here, we discuss the current understanding of the MMCs function in immunity and lingering questions. We suggest additional experiments needed to confirm that MMCs serve a GC-like role in fish immunity. Finally, we address the utility of the MMC as a broadly applicable histological indicator of the fish (as well as amphibian and reptilian) immune response in both laboratory and wild populations of both model and non-model vertebrates. We highlight the factors (sex, pollution exposure, stress, stocking density, etc.) that should be considered when using MMCs to study immunity in non-model vertebrates in wild populations.
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Affiliation(s)
- Natalie C Steinel
- Department of Integrative Biology, The University of Texas at Austin, Austin, TX, United States.,Department of Medical Education, Dell Medical School, The University of Texas at Austin, Austin, TX, United States
| | - Daniel I Bolnick
- Department of Integrative Biology, The University of Texas at Austin, Austin, TX, United States
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Yadava K, Bollyky P, Lawson MA. The formation and function of tertiary lymphoid follicles in chronic pulmonary inflammation. Immunology 2016; 149:262-269. [PMID: 27441396 PMCID: PMC5046054 DOI: 10.1111/imm.12649] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2016] [Revised: 07/01/2016] [Accepted: 07/06/2016] [Indexed: 12/13/2022] Open
Abstract
Tertiary lymphoid follicles (TLFs) can develop in the respiratory tract in response to infections or chronic inflammation. However, their functional relevance remains unclear because they are implicated in both protective and pathological responses. In contrast to homeostatic conditions, external antigens and damage to the lung tissue may drive TLF formation in inflamed lungs, and once established, the presence of pulmonary TLFs may signal the progression of chronic lung disease. This novel concept will be discussed in light of recent work in chronic obstructive pulmonary disease and how changes in the pulmonary microbiota may drive and direct TLF formation and function. We will also discuss the cellularity of TLFs at the pulmonary mucosa, with emphasis on the potential roles of lymphoid tissue inducer cells, and B- and T-cell aggregates, and will examine the function of key chemokines and cytokines including CXCL13 and interleukin-17, in the formation and maintenance of pulmonary TLFs.
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Affiliation(s)
- Koshika Yadava
- Department of Medicine, Stanford University School of Medicine, Stanford, CA, USA.
| | - Paul Bollyky
- Department of Medicine, Stanford University School of Medicine, Stanford, CA, USA
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