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A special issue of International Journal of Molecular Sciences (ISSN 1422-0067). This special issue belongs to the section "Molecular Immunology".

Deadline for manuscript submissions: closed (30 April 2020) | Viewed by 51493

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Special Issue Editors

Dr. Alberto Cuesta

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Guest Editor

Department of Cell Biology and Histology, Faculty of Biology, Campus Regional de Excelencia Internacional “Campus Mare Nostrum”, University of Murcia, 30100 Murcia, Spain
Interests: fish, immunology; virus, AMPs; toxicology; cell lines; vaccines; aquaculture; biotechnology
Special Issues, Collections and Topics in MDPI journals

Dr. Elena Chaves-Pozo

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Co-Guest Editor

Centro Oceanográfico de Murcia (COMU-IEO), CSIC, Carretera de la Azohía s/n, Puerto de Mazarrón, 30860 Murcia, Spain
Interests: immune-reproductive responses; marine fish; viral transmission through the gonad; endocrine disruption
Special Issues, Collections and Topics in MDPI journals

Special Issue Information

Dear Colleagues,

A Special Issue on the topic of “Fish Immunology” is being launched by the International Journal of Molecular Sciences. Fish represent a fascinating research model in immunology, because they were the first group during animal evolution to have a complete and functional immune system comprising a diverse and interconnected array of both innate and acquired immune tissues, cells, and molecules. Apart from this, the spectacular growth of aquaculture production for human nutrition has attracted the focus of many researchers all over the world for practical and applied purposes. In addition, the implementation of the zebrafish as a biomedicine model is extending the interests and potential of fish biology, including immunology. This Special Issue aims to gather new research and applied topics in the field of fish immunology at the molecular level, including, but not limited to, issues relating to immunoglobulins, toll-like receptors, chemokines, interferons, lectins, acute-phase proteins, interleukins, antimicrobial peptides, and inflammation, as well as leucocyte types, distribution and trafficking, maturation and molecular markers, vaccines, response to pathogens, immune regulation, evolution, and so on. Reviews or research articles in this fascinating area, which discuss the benefits of using fish as models of study and their applications or which aim to discern the bottlenecks in the field, are welcome.

Dr. Alberto Cuesta
Dr. Elena Chaves-Pozo
Guest Editors

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Keywords

fish immunology
innate immunity
acquired immunity
leucocytes
disease
immunostimulants
immunodepression
inflammation

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Related Special Issues

Fish Immunology 2.0 in International Journal of Molecular Sciences (17 articles)
Fish Immunology: 4th Edition in International Journal of Molecular Sciences (9 articles)

Published Papers (12 papers)

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Research

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16 pages, 3440 KiB

Open AccessArticle

Characterization of CD4-Positive Lymphocytes in the Antiviral Response of Olive Flounder (Paralichthys oliveceus) to Nervous Necrosis Virus

by Jae Wook Jung, Jin Hong Chun, Jung Seok Lee, Si Won Kim, Ae Rin Lee, Jaesung Kim, Jassy Mary S. Lazarte, Young Rim Kim, Hyoung Jun Kim, Kim D. Thompson and Tae Sung Jung

Int. J. Mol. Sci. 2020, 21(11), 4180; https://doi.org/10.3390/ijms21114180 - 11 Jun 2020

Cited by 15 | Viewed by 3131

Abstract

The presence of CD4 T lymphocytes has been described for several teleost species, while many of the main T cell subsets have not been characterized at a cellular level, because of a lack of suitable tools for their identification, e.g., monoclonal antibodies (mAbs) against cell markers. We previously described the tissue distribution and immune response related to CD3ε and CD4-1 T cells in olive flounder (Paralichthys oliveceus) in response to a viral infection. In the present study, we successfully produce an mAb against CD4-2 T lymphocytes from olive flounder and confirmed its specificity using immuno-blotting, immunofluorescence staining, flow cytometry analysis and reverse transcription polymerase chain reaction (RT-PCR). Using these mAbs, we were able to demonstrate that the CD3ε T cell populations contain both types of CD4⁺ cells, with the majority of the CD4 T cell subpopulations being CD4-1⁺/CD4-2⁺ cells, determined using two-color flow cytometry analysis. We also examined the functional activity of the CD4-1 and CD4-2 cells in vivo in response to a viral infection, with the numbers of both types of CD4 T cells increasing significantly during the virus infection. Collectively, these findings suggest that the CD4 T lymphocytes in olive flounder are equivalent to the helper T cells in mammals in terms of their properties and function, and it is the CD4-2 T lymphocytes rather than the CD4-1 T cells that play an important role in the Th1 immune response against viral infections in olive flounder. Full article

(This article belongs to the Special Issue Fish Immunology)

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22 pages, 2029 KiB

Open AccessArticle

Characterization of miRNAs in Cultured Atlantic Salmon Head Kidney Monocyte-Like and Macrophage-Like Cells

by Nicole C. Smith, Sherri L. Christian, Nardos T. Woldemariam, Kathy A. Clow, Matthew L. Rise and Rune Andreassen

Int. J. Mol. Sci. 2020, 21(11), 3989; https://doi.org/10.3390/ijms21113989 - 2 Jun 2020

Cited by 14 | Viewed by 4270

Abstract

Macrophages are among the first cells to respond to infection and disease. While microRNAs (miRNAs) are involved in the process of monocyte-to-macrophage differentiation in mammals, less is known in teleost fish. Here, Atlantic salmon head kidney leukocytes (HKLs) were used to study the expression of miRNAs in response to in vitro culture. The morphological analysis of cultures showed predominantly monocyte-like cells on Day 1 and macrophage-like cells on Day 5, suggesting that the HKLs had differentiated from monocytes to macrophages. Day 5 HKLs also contained a higher percentage of phagocytic cells. Small RNA sequencing and qPCR analysis were applied to examine the miRNA diversity and expression. There were 370 known mature Atlantic salmon miRNAs in HKLs. Twenty-two miRNAs (15 families) were downregulated while 44 miRNAs (25 families) were upregulated on Day 5 vs. Day 1. Mammalian orthologs of many of the differentially expressed (DE) miRNAs are known to regulate macrophage activation and differentiation, while the teleost-specific miR-2188, miR-462 and miR-731 were also DE and are associated with immune responses in fish. In silico predictions identified several putative target genes of qPCR-validated miRNAs associated with vertebrate macrophage differentiation. This study identified Atlantic salmon miRNAs likely to influence macrophage differentiation, providing important knowledge for future functional studies. Full article

(This article belongs to the Special Issue Fish Immunology)

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18 pages, 3592 KiB

Open AccessArticle

Transcriptome Analysis of Maternal Gene Transcripts in Unfertilized Eggs of Misgurnus anguillicaudatus and Identification of Immune-Related Maternal Genes

by Chan-Hee Kim, Eun Jeong Kim, Chaehwa Seo and Yoon Kwon Nam

Int. J. Mol. Sci. 2020, 21(11), 3872; https://doi.org/10.3390/ijms21113872 - 29 May 2020

Cited by 6 | Viewed by 2884

Abstract

Maternal genes are important in directing early development and determining egg quality in fish. We here report the de novo transcriptome from four tissue libraries of the cyprinid loach, Misgurnus anguillicaudatus, and for the first time identified maternal gene transcripts in unfertilized eggs and suggest their immune system involvement. Expression profiles and functional enrichment revealed a total 24,116 transcripts were expressed as maternal transcripts in unfertilized eggs, which were involved in a wide range of biological functions and pathways. Comparison expression profiles and analysis of tissue specificity revealed that the large numbers of maternal transcripts were stored in unfertilized eggs near the late phase of ovarian maturation and before ovulation. Functional classification showed a total of 279 maternal immune-related transcripts classified with immune system process GO term and immune system KEGG pathway. qPCR analysis showed that transcript levels of identified maternal immune-related candidate genes were dynamically modulated during development and early ontogeny of M. anguillicaudatus. Taken together, this study could not only provide knowledge on the protective roles of maternal immune-related genes during early life stage of M. anguillicaudatus but could also be a valuable transcriptomic/genomic resource for further analysis of maternally provisioned genes in M. anguillicaudatus and other related teleost fishes. Full article

(This article belongs to the Special Issue Fish Immunology)

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15 pages, 2511 KiB

Open AccessArticle

Identification and Regulation of Interleukin-17 (IL-17) Family Ligands in the Teleost Fish European Sea Bass

by Carmen González-Fernández, Elena Chaves-Pozo and Alberto Cuesta

Int. J. Mol. Sci. 2020, 21(7), 2439; https://doi.org/10.3390/ijms21072439 - 31 Mar 2020

Cited by 26 | Viewed by 4226

Abstract

Interleukin-17 (IL-17) cytokine comprises a family of six ligands in mammals with proinflammatory functions, having an important role in autoimmune disorders and against bacterial, viral, and fungal pathogens. While IL-17A and IL-17F ligands are mainly produced by Th cells (Th17 cells), the rest of the ligands are expressed by other immune and non-immune cells and have different functions. The identification of IL-17 ligands in fish has revealed the presence of six members, counterparts to mammalian ones, and a teleost-specific form, the fish IL-17N. However, tissue distribution, the regulation of gene expression, and scarce bioactivity assays point to similar functions compared to mammalian ones, though this yet to be investigated and confirmed. Thus, we have identified seven IL-17 ligands in the teleost European sea bass (Dicentrarchus labrax), for the first time, corresponding to IL-17A/F1, IL-17A/F2, IL-17A/F3, IL-17C1, IL-17C2, IL-17D, and IL-17N, according to the predicted protein sequences and phylogenetic analysis. They are constitutively and widely transcribed in sea bass tissues, with some of them being mainly expressed in the thymus, brain or intestine. Upon in vitro stimulation of head-kidney leucocytes, the mRNA levels of all sea bass IL-17 ligands were up-regulated by phytohemagglutinin treatment, a well-known T cell mitogen, suggesting a major expression in T lymphocytes. By contrast, the infection of sea bass juveniles with nodavirus (NNV), a very pathogenic virus for this fish species, resulted in the up-regulation of the transcription of IL-17C1 in the head-kidney and of IL-17C1 and IL-17D in the brain, the target tissue for NNV replication. By contrast, NNV infection led to a down-regulated transcription of IL-17A/F1, IL-17A/F2, IL-17C1, IL-17C2, and IL-17D in the head-kidney and of IL-17A/F1 and IL-17A/F3 in the brain. The data are discussed accordingly with the IL-17 ligand expression and the immune response under the different situations tested. Full article

(This article belongs to the Special Issue Fish Immunology)

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45 pages, 47806 KiB

Open AccessArticle

Transcriptomic Profiling in Fins of Atlantic Salmon Parasitized with Sea Lice: Evidence for an Early Imbalance Between Chalimus-Induced Immunomodulation and the Host’s Defense Response

by Navaneethaiyer Umasuthan, Xi Xue, Albert Caballero-Solares, Surendra Kumar, Jillian D. Westcott, Zhiyu Chen, Mark D. Fast, Stanko Skugor, Barbara F. Nowak, Richard G. Taylor and Matthew L. Rise

Int. J. Mol. Sci. 2020, 21(7), 2417; https://doi.org/10.3390/ijms21072417 - 31 Mar 2020

Cited by 27 | Viewed by 5519

Abstract

Parasitic sea lice (e.g., Lepeophtheirus salmonis) cause costly outbreaks in salmon farming. Molecular insights into parasite-induced host responses will provide the basis for improved management strategies. We investigated the early transcriptomic responses in pelvic fins of Atlantic salmon parasitized with chalimus I stage sea lice. Fin samples collected from non-infected (i.e., pre-infected) control (PRE) and at chalimus-attachment sites (ATT) and adjacent to chalimus-attachment sites (ADJ) from infected fish were used in profiling global gene expression using 44K microarrays. We identified 6568 differentially expressed probes (DEPs, FDR < 5%) that included 1928 shared DEPs between ATT and ADJ compared to PRE. The ATT versus ADJ comparison revealed 90 DEPs, all of which were upregulated in ATT samples. Gene ontology/pathway term network analyses revealed profound changes in physiological processes, including extracellular matrix (ECM) degradation, tissue repair/remodeling and wound healing, immunity and defense, chemotaxis and signaling, antiviral response, and redox homeostasis in infected fins. The QPCR analysis of 37 microarray-identified transcripts representing these functional themes served to confirm the microarray results with a significant positive correlation (p < 0.0001). Most immune/defense-relevant transcripts were downregulated in both ATT and ADJ sites compared to PRE, suggesting that chalimus exerts immunosuppressive effects in the salmon’s fins. The comparison between ATT and ADJ sites demonstrated the upregulation of a suite of immune-relevant transcripts, evidencing the salmon’s attempt to mount an anti-lice response. We hypothesize that an imbalance between immunomodulation caused by chalimus during the early phase of infection and weak defense response manifested by Atlantic salmon makes it a susceptible host for L. salmonis. Full article

(This article belongs to the Special Issue Fish Immunology)

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23 pages, 7199 KiB

Open AccessArticle

Co-Expression Network Analysis of Spleen Transcriptome in Rock Bream (Oplegnathus fasciatus) Naturally Infected with Rock Bream Iridovirus (RBIV)

by Ahran Kim, Dahye Yoon, Yunjin Lim, Heyong Jin Roh, Suhkmann Kim, Chan-Il Park, Heui-Soo Kim, Hee-Jae Cha, Yung Hyun Choi and Do-Hyung Kim

Int. J. Mol. Sci. 2020, 21(5), 1707; https://doi.org/10.3390/ijms21051707 - 2 Mar 2020

Cited by 19 | Viewed by 5216

Abstract

Rock bream iridovirus (RBIV) is a notorious agent that causes high mortality in aquaculture of rock bream (Oplegnathus fasciatus). Despite severity of this virus, no transcriptomic studies on RBIV-infected rock bream that can provide fundamental information on protective mechanism against the virus have been reported so far. This study aimed to investigate physiological mechanisms between host and RBIV through transcriptomic changes in the spleen based on RNA-seq. Depending on infection intensity and sampling time point, fish were divided into five groups: uninfected healthy fish at week 0 as control (0C), heavy infected fish at week 0 (0H), heavy mixed RBIV and bacterial infected fish at week 0 (0MH), uninfected healthy fish at week 3 (3C), and light infected fish at week 3 (3L). We explored clusters from 35,861 genes with Fragments Per Kilo-base of exon per Million mapped fragments (FPKM) values of 0.01 or more through signed co-expression network analysis using WGCNA package. Nine of 22 modules were highly correlated with viral infection (|gene significance (GS) vs. module membership (MM) |> 0.5, p-value < 0.05). Expression patterns in selected modules were divided into two: heavy infected (0H and 0MH) and control and light-infected groups (0C, 3C, and 3L). In functional analysis, genes in two positive modules (5448 unigenes) were enriched in cell cycle, DNA replication, transcription, and translation, and increased glycolysis activity. Seven negative modules (3517 unigenes) built in this study showed significant decreases in the expression of genes in lymphocyte-mediated immune system, antigen presentation, and platelet activation, whereas there was significant increased expression of endogenous apoptosis-related genes. These changes lead to RBIV proliferation and failure of host defense, and suggests the importance of blood cells such as thrombocytes and B cells in rock bream in RBIV infection. Interestingly, a hub gene, pre-mRNA processing factor 19 (PRPF19) showing high connectivity (kME), and expression of this gene using qRT-PCR was increased in rock bream blood cells shortly after RBIV was added. It might be a potential biomarker for diagnosis and vaccine studies in rock bream against RBIV. This transcriptome approach and our findings provide new insight into the understanding of global rock bream-RBIV interactions including immune and pathogenesis mechanisms. Full article

(This article belongs to the Special Issue Fish Immunology)

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14 pages, 2643 KiB

Open AccessArticle

Secretory Production of Functional Grouper Type I Interferon from Epinephelus septemfasciatus in Escherichia coli and Bacillus subtilis

by Hsuan-Ju Lin, Joan Tang Xiao Joe, Wen-Jung Lu, Mei-Ying Huang, Ting-Hsuan Sun, Sheng-Pao Lin, Yi-Chuan Li, Ya-Chin Tsui, Ming-Wei Lu and Hong-Ting Victor Lin

Int. J. Mol. Sci. 2020, 21(4), 1465; https://doi.org/10.3390/ijms21041465 - 21 Feb 2020

Cited by 2 | Viewed by 3593

Abstract

Nervous necrosis virus (NNV) results in high mortality rates of infected marine fish worldwide. Interferons (IFNs) are cytokines in vertebrates that suppress viral replication and regulate immune responses. Heterologous overexpression of fish IFN in bacteria could be problematic because of protein solubility and loss of function due to protein misfolding. In this study, a protein model of the IFN-α of Epinephelus septemfasciatus was built based on comparative modeling. In addition, PelB and SacB signal peptides were fused to the N-terminus of E. septemfasciatus IFN-α for overexpression of soluble, secreted IFN in Escherichia coli (E-IFN) and Bacillus subtilis (B-IFN). Cytotoxicity tests indicated that neither recombinant grouper IFN-α were cytotoxic to a grouper head kidney cell line (GK). The GK cells stimulated with E-IFN and B-IFN exhibited elevated expression of antiviral Mx genes when compared with the control group. The NNV challenge experiments demonstrated that GK cells pretreated or co-treated with E-IFN and B-IFN individually had three times the cell survival rates of untreated cells, indicating the cytoprotective ability of our recombinant IFNs. These data provide a protocol for the production of soluble, secreted, and functional grouper IFN of high purity, which may be applied to aquaculture fisheries for antiviral infection. Full article

(This article belongs to the Special Issue Fish Immunology)

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13 pages, 2119 KiB

Open AccessArticle

An iTRAQ-Based Comparative Proteomics Analysis of the Biofilm and Planktonic States of Aeromonas veronii TH0426

by Ying Li, Bintong Yang, Jiaxin Tian, Wuwen Sun, Guiqin Wang, Aidong Qian, Chunfeng Wang, Xiaofeng Shan and Yuanhuan Kang

Int. J. Mol. Sci. 2020, 21(4), 1450; https://doi.org/10.3390/ijms21041450 - 20 Feb 2020

Cited by 4 | Viewed by 2866

Abstract

Aeromonas veronii is a virulent fish pathogen that causes extensive economic losses in the aquaculture industry worldwide. In this study, a virulent strain of A. veronii TH0426 was used to establish an in vitro biofilm model. The results show that the biofilm-forming abilities of A. veronii TH0426 were similar in different media, peaking under conditions of 20 °C and pH 6. Further, isobaric tags for relative and absolute quantitation (iTRAQ)-based quantitative proteomics methods were used to compare the differential expression of A. veronii between the biofilm and planktonic cells. The results show alterations in 277 proteins, with 130 being upregulated and 147 downregulated. Pathway analysis and GO (Gene Ontology) annotations indicated that these proteins are mainly involved in metabolic pathways and the biosynthesis of secondary metabolites and antibiotics. These proteins are the main factors affecting the adaptability of A. veronii to its external environment. MRM (multiple reaction 27 monitoring) and qPCR (qPCR) were used to verify the differential proteins of the selected A. veronii. This is the first report on the biofilm and planktonic cells of A. veronii, thus contributing to studying the infection and pathogenesis of A. veronii. Full article

(This article belongs to the Special Issue Fish Immunology)

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19 pages, 2314 KiB

Open AccessArticle

Differential Effects of Dietary Supplementation of Krill Meal, Soybean Meal, Butyrate, and Bactocell^® on the Gene Expression of Atlantic Salmon Head Kidney

by Mahsa Jalili, Marco Gerdol, Samuele Greco, Alberto Pallavicini, Francesco Buonocore, Giuseppe Scapigliati, Simona Picchietti, Maria Angeles Esteban, Morten Rye and Atle Bones

Int. J. Mol. Sci. 2020, 21(3), 886; https://doi.org/10.3390/ijms21030886 - 30 Jan 2020

Cited by 10 | Viewed by 4074

Abstract

The head kidney is a key organ that plays a fundamental role in the regulation of the fish immune response and in the maintenance of endocrine homeostasis. Previous studies indicate that the supplementation of exogenous dietary components, such as krill meal (KM), soybean meal (SM), Bactocell^® (BA), and butyrate (BU), can have a significant effect on the immune function of the head kidney. The aim of this study was to investigate the differential effect of these four dietary ingredients on the transcriptional profiles of the head kidney of the Atlantic salmon. This study revealed that just a small number of genes were responsive to the feeding regime after a long-term (12 weeks) treatment, and evidenced that the most significant alterations, both in terms of the number of affected genes and magnitude of changes in gene expression, were detectable in the BU- and KM-fed groups compared with controls, while the SM diet had a nearly negligible effect, and BA had no significant effects at all. Most of the differentially expressed genes were involved in the immune response and, in line with data previously obtained from pyloric caeca, major components of the complement system were significantly affected. These alterations were accompanied by an increase in the density of melanomacrophage centers in the KM- and SM-fed group and their reduction in the BU-fed group. While three types of dietary supplements (BU, KM, and SM) were able to produce a significant modulation of some molecular players of the immune system, the butyrate-rich diet was revealed as the one with the most relevant immune-stimulating properties in the head kidney. These preliminary results suggest that further investigations should be aimed towards the elucidation of the potential beneficial effects of butyrate and krill meal supplementation on farmed salmon health and growth performance. Full article

(This article belongs to the Special Issue Fish Immunology)

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14 pages, 2972 KiB

Open AccessArticle

Functional Analysis of preA in Aeromonas veronii TH0426 Reveals a Key Role in the Regulation of Virulence and Resistance to Oxidative Stress

by Bintong Yang, Haichao Song, Dingjie An, Dongxing Zhang, Sayed Haidar Abbas Raza, Guiqin Wang, Xiaofeng Shan, Aidong Qian, Yuanhuan Kang and Chunfeng Wang

Int. J. Mol. Sci. 2020, 21(1), 98; https://doi.org/10.3390/ijms21010098 - 21 Dec 2019

Cited by 10 | Viewed by 2728

Abstract

Aeromonas veronii is one of the main pathogens causing freshwater fish sepsis and ulcer syndrome. This bacterium has caused serious economic losses in the aquaculture industry worldwide, and it has become an important zoonotic and aquatic agent. However, little is known about the molecular mechanism of pathogenesis of A. veronii. In this study, we first constructed an unmarked mutant strain (ΔpreA) by generating an in-frame deletion of the preA gene, which encodes a periplasmic binding protein, to investigate its role in A. veronii TH0426. Our results showed that the motility and biofilm formation ability of ΔpreA were similar to those of the wild-type strain. However, the adhesion and invasion ability in epithelioma papulosum cyprini (EPC) cells were significantly enhanced (2.0-fold). Furthermore, the median lethal dose (LD₅₀) of ΔpreA was 7.6-fold higher than that of the wild-type strain, which illustrates that the virulence of the mutant was significantly enhanced. This finding is also supported by the cytotoxicity test results, which showed that the toxicity of ΔpreA to EPC cells was enhanced 1.3-fold relative to the wild type. Conversely, tolerance test results showed that oxidative stress resistance of ΔpreA decreased 5.9-fold compared to with the wild-type strain. The results suggest that preA may negatively regulate the virulence of A. veronii TH0426 through the regulation of resistance to oxidative stress. These insights will help to further elucidate the function of preA and understand the pathogenesis of A. veronii. Full article

(This article belongs to the Special Issue Fish Immunology)

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13 pages, 4567 KiB

Open AccessArticle

Oral Administration of Lactobacillus Casei Expressing Flagellin A Protein Confers Effective Protection against Aeromonas Veronii in Common Carp, Cyprinus Carpio

by Jia-Xin Tian, Yuan-Huan Kang, Guo-Sheng Chu, Hong-Jian Liu, Yi-Di Kong, Lin-Hui Zhao, Yu-Xin Kong, Xiao-Feng Shan and Gui-Qin Wang

Int. J. Mol. Sci. 2020, 21(1), 33; https://doi.org/10.3390/ijms21010033 - 19 Dec 2019

Cited by 23 | Viewed by 3708

Abstract

Aeromonas veronii is a pathogen capable of infecting humans, livestock and aquatic animals, resulting in serious economic losses. In this study, two recombinant Lactobacillus casei expressing flagellin A (FlaA) of A. veronii, Lc-pPG-1-FlaA (surface-displayed) and Lc-pPG-2-FlaA (secretory) were constructed. The immune responses in fish administered with recombinant L. casei were evaluated. The two recombinant L. casei were orally administered to common carp, which stimulated high serum IgM and induced higher ACP, AKP, SOD and LYZ activity. Using qRT-PCR, the expression of IL-10, IL-8, IL-1β, TNF-α and IFN-γ in the tissue of fish immunized with recombinant L. casei was significantly (p < 0.05) upregulated, which indicated that recombinant L. casei could activate the innate immune system to trigger the cell immune response and inflammatory response. Furthermore, recombinant L. casei was able to survive the intestinal environment and colonize in intestine mucosal. The study showed that after being challenged by A. veronii, fish administered with Lc-pPG-1-FlaA (70%) and Lc-pPG-2-FlaA (50%) had higher survival rates compared to Lc-pPG and PBS, indicating that recombinant L. casei might prevent A. veronii infection by activating the immune system to trigger immune responses. We demonstrated that flagellin as an antigen of vaccine, is acceptable for preventing A. veronii infection in fish. The recombinant L. casei expressing FlaA may be a novel mucosal vaccine for treating and controlling A. veronii. Full article

(This article belongs to the Special Issue Fish Immunology)

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Role of Macrophages and Microglia in Zebrafish Regeneration

by Susanna R. Var and Christine A. Byrd-Jacobs

Int. J. Mol. Sci. 2020, 21(13), 4768; https://doi.org/10.3390/ijms21134768 - 5 Jul 2020

Cited by 30 | Viewed by 7870

Abstract

Currently, there is no treatment for recovery of human nerve function after damage to the central nervous system (CNS), and there are limited regenerative capabilities in the peripheral nervous system. Since fish are known for their regenerative abilities, understanding how these species modulate inflammatory processes following injury has potential translational importance for recovery from damage and disease. Many diseases and injuries involve the activation of innate immune cells to clear damaged cells. The resident immune cells of the CNS are microglia, the primary cells that respond to infection and injury, and their peripheral counterparts, macrophages. These cells serve as key modulators of development and plasticity and have been shown to be important in the repair and regeneration of structure and function after injury. Zebrafish are an emerging model for studying macrophages in regeneration after injury and microglia in neurodegenerative disorders such as Parkinson’s disease and Alzheimer’s disease. These fish possess a high degree of neuroanatomical, neurochemical, and emotional/social behavioral resemblance with humans, serving as an ideal simulator for many pathologies. This review explores literature on macrophage and microglial involvement in facilitating regeneration. Understanding innate immune cell behavior following damage may help to develop novel methods for treating toxic and chronic inflammatory processes that are seen in trauma and disease. Full article

(This article belongs to the Special Issue Fish Immunology)

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