Molecular characterisation of four class 2 cytokine receptor family members in rainbow trout, Oncorhynchus mykiss

Interleukin-26 in channel catfish (Ictalurus punctatus): Molecular characterization and immune functional activity

IL-26 is a crucial inflammatory cytokine that participates in defending host cells against infections. We initially cloned and identified the cDNA sequences of interleukin (IL)-26 in channel catfish (Ictalurus punctatus). The open reading frame (ORF) of IpIL-26 was 537 bp in length, encoding 178 amino acids (aa). Constitutive expression of IpIL-26 was observed in tested tissues, with the highest level found in the gill and spleen. To explore the function of IpIL-26 in channel catfish, different stimuli were used to act on both channel catfish and channel catfish kidney cells (CCK). The expression of IpIL-26 could be up-regulated by bacteria and viruses in multiple tissues. In vitro, recombinant IpIL-26 (rIpIL-26) could induce the expression levels of inflammatory cytokines such as TNF-α, IL-1β, IL-6, IL-20, and IL-22 playing vital roles in defending the host against infections. Our results demonstrated that IpIL-26 might be an essential cytokine, significantly affecting the immune defense of channel catfish against pathogen infections.

Effects of diets rich in Agaricus bisporus polysaccharides on the growth, antioxidant, immunity, and resistance to Yersinia ruckeri in channel catfish

To promote the application of Agaricus bisporus polysaccharides (ABPs) in channel catfish (Ictalurus punctatus) culture, we evaluated the effects of ABPs on the growth, immunity, antioxidant, and antibacterial activity of channel catfish. When the amount of ABPs was 250 mg/kg, channel catfish's weight gain and specific growth rates increased significantly while the feed coefficient decreased. We also found that adding ABPs in the feed effectively increased the activities of ACP, MDA, T-SOD, AKP, T-AOC, GSH, and CAT enzymes and immune-related genes such as IL-1β, Hsp70, and IgM in the head kidney of channel catfish. Besides, long-term addition will not cause pathological damage to the head kidney. When the amount of ABPs was over 125 mg/kg, the protection rate of channel catfish was more than 60%. According to the intestinal transcriptome analysis, the addition of ABPs promoted the expression of intestinal immunity genes and growth metabolism-related genes and enriched multiple related KEEG pathways. When challenged by Yersinia ruckeri infection, the immune response of channel catfish fed with ABPs was intenser and quicker. Additionally, the 16S rRNA gene sequencing analysis showed that the composition of the intestinal microbial community of channel catfish treated with ABPs significantly changed, and the abundance of microorganisms beneficial to channel catfish growth, such as Firmicutes and Bacteroidota increased. In conclusion, feeding channel catfish with ABPs promoted growth, enhanced immunity and antioxidant, and improved resistance to bacterial infections. Our current results might promote the use of ABPs in channel catfish and even other aquacultured fish species.

Molecular characterization of nineteen cytokine receptor family B (CRFB) members, CRFB1, CRFB2, CRFB4-17, with three CRFB9 and two CRFB14 in a cyprinid fish, the blunt snout bream Megalobrama amblycephala

The class II cytokine receptor family members are receptors of class 2 helical cytokines in mammals, and are named cytokine receptor family B (CRFB) in fish. In zebrafish, sixteen members, including CRFB1, CRFB2 and CRFB4-17 were reported. With the availability of genome sequence, a total of nineteen CRFBs was identified in the blunt snout bream (Megalobrama amblycephala), including CRFB1, CRFB2, CRFB4-17 with the presence of three CRFB9 isoforms, and two CRFB14 isoforms. These CRFB molecules contain well conserved features, such as fibronectin type III (FNIII) domain, transmembrane and intracellular domains as other class II cytokine receptors, and are phylogenetically grouped into thirteen clades with their homologues from other species of fish. The CRFB genes were constitutively expressed in organs/tissues examined in the fish. The finding of more CRFB members in the bream may provide clues to understand possible receptor-ligand interaction and their diversity from an evolutionary point of view.

Grass carp IL-20 binds to IL-20R2 but induces STAT3 phosphorylation via IL-20R1

IL-20 is a pleiotropic cytokine that belongs to the IL-10 family and has a variety of biological functions in tissue homeostasis and regulation of host immune defenses. It signals through a heterodimeric receptor composed of a subunit with a long intracellular domain (R1 type receptor) and a subunit with a short intracellular domain (R2 type receptor). In this study, the R1 type receptor (CiIL-20R1/CRFB8) and the R2 type receptor (CiIL-20R2/CRFB16) were identified in grass carp Ctenopharyngodon idella. Expression analysis revealed that IL-20R2 was highly expressed in the gills and skin in healthy fish. Infection with Flavobacterium columnare resulted in the downregulation of both receptors in the gill at 48 and 72 h, whilst infection with grass carp reovirus induced their expression in the head kidney and spleen at 72 h. In the primary head kidney leucocytes, the expression levels of IL-20R1 and IL-20R2 were decreased after stimulation with 250 ng/mL IL-1β but not affected by IFN-γ. Co-immunoprecipitation analysis showed that CiIL-20R2/CRFB16 but not CiIL-20R1/CRFB8 bound to CiIL-20L. Furthermore, it was shown that CiIL-20R1/CRFB8 was responsible for activating the phosphorylation of STAT3, whilst CiIL-20R2/CRFB16 was not involved. Structural modeling analysis showed that key residues involved in the interaction between IL-20 and receptors were highly conserved between grass carp and humans, suggesting that the signal transduction and functions of IL-20/IL-20R axis are evolutionarily conserved.

Identification and establishment of type IV interferon and the characterization of interferon-υ including its class II cytokine receptors IFN-υR1 and IL-10R2

Interferons (IFNs) are critical soluble factors in the immune system and are composed of three types, (I, II and III) that utilize different receptor complexes IFN-αR1/IFN-αR2, IFN-γR1/IFN-γR2, and IFN-λR1/IL-10R2, respectively. Here we identify IFN-υ from the genomic sequences of vertebrates. The members of class II cytokine receptors, IFN-υR1 and IL-10R2, are identified as the receptor complex of IFN-υ, and are associated with IFN-υ stimulated gene expression and antiviral activity in zebrafish (Danio rerio) and African clawed frog (Xenopus laevis). IFN-υ and IFN-υR1 are separately located at unique and highly conserved loci, being distinct from all other three-type IFNs. IFN-υ and IFN-υR1 are phylogenetically clustered with class II cytokines and class II cytokine receptors, respectively. Therefore, the finding of this IFN ligand-receptor system may be considered as a type IV IFN, in addition to the currently recognized three types of IFNs in vertebrates.

Interferons are critical soluble components of the inflammatory process and are composed of three types with associated receptor complexes. Here the authors identify and characterise the type IV interferon, IFN-υ, and identify its associated receptors, denote functionality during in vivo infection and ascertain its genomic localisation.

Comprehensive comparison of thirteen kinds of cytokine receptors from the endangered fish Chinese sturgeon (Acipenser sinensis)

The interferon receptor system in teleost fish is more complex than that in mammals. In the present study, we identified 13 cytokine receptor genes (10 interferon receptor genes and 3 IL10R2-like genes) from Chinese sturgeon (Acipenser sinensis) using RNA-sequencing. Sequence analysis indicated that these receptors had conserved domains, including signal peptides, FNⅢ, and transmembrane domains. Phylogenetic analysis suggested that they belonged to the cytokine receptor family. In the present study, we named them IFNAR1-like (CRFB5a, CRFB5b), IFNAR2-like (CRFB3a, CRFB3b), IFNGR1-like (IFNGR1), IFNGR2-like (CRFB6a, CRFB6b/IFNGR2-1, CRFB6c/IFNGR2-2, CRFB6d/IFNGR2-3, CRFB6e/IFNGR2-4) and IL10R2-like (CRFB4a, CRFB4b, CRFB4c), respectively. Constitutive expression analysis revealed that these receptor genes had potential functions in immune and non-immune tissue compartments. After stimulating with Poly (I:C), the expression fold changes of CRFB3a, CRFB4a, CRFB4b, CRFB5b, and CRFB6e/IFNGR2-4 in Chinese sturgeon were higher than those of other receptor genes, which revealed that these five genes had important functions in the immune process to resist virus invasion in the host. After stimulating with IFN gamma, the expression fold changes of CRFB3a, CRFB4a, and CRFB6b/IFNGR2-1 were higher than those other receptor genes. Based on other teleost fish interferon receptor models, we speculated that IFNAR1-like (CRFB5a, CRFB5b) and IFNAR2-like (CRFB3a, CRFB3b), comprised Chinese sturgeon type Ⅰ IFN receptors; and IFNGR1-like (IFNGR1) and IFNGR2-like (CRFB6/IFNGR2) comprised Chinese sturgeon type Ⅱ IFN receptors.

Tongue sole (Cynoglossus semilaevis) interleukin 10 receptors are involved in the immune response against bacterial infection

Interleukin (IL)-10, an immune-regulatory cytokine, exerts various biological functions through interaction with IL-10 receptors. In teleost, very limited functional studies on IL-10 receptors have been documented. In this study, we reported the expression patterns of IL-10 receptor 1 (CsIL-10R1) and receptor 2 (CsIL-10R2) of tongue sole (Cynoglossus semilaevis) and examined their biological properties. The expression of CsIL-10R1 and CsIL-10R2 occurred in multiple tissues and were regulated by bacterial challenge. In vitro binding studies showed that recombinant extracellular region of CsIL-10R1 (rCsIL-10R1ex) rather than rCsIL-10R2ex could bind with rCsIL-10. Cellular study showed that both CsIL-10R1 and CsIL-10R2 were expressed on peripheral blood leukocytes (PBLs), and blockade of CsIL-10R1 or CsIL-10R2 by antibody could reduce inhibitory effect of CsIL-10 on ROS production of PBLs. When injected in vivo, anti-rCsIL-10R1 or anti-rCsIL-10R2 antibody dramatically promoted the expression of proinflammatory cytokines and suppressed bacterial dissemination in tongue sole tissues. Consistently, the overexpression of CsIL-10R1 or CsIL-10R2 significantly enhanced bacterial dissemination, and the overexpression of CsIL-10R1M bearing STAT3 site mutation reduced bacterial dissemination. Overall, these results demonstrate for the first time teleost IL-10 receptors play a negative role in antibacterial immunity and add insight into the function of CsIL-10 receptors.

Cloning and characterisation of type I interferon receptor 1 in orange-spotted grouper (Epinephelus coioides) for response to nodavirus infection

Grouper is known as a highly economical teleost species in the Asian aquaculture industry; however, intensive culture activities easily cause disease outbreak, especially viral disease. For the prevention of viral outbreaks, interferon (IFN) is among the major defence systems being studied in different species. Fish type I IFNs are known to possess antiviral properties similar to mammalian type I IFNs. In order to stimulate antiviral function, IFN will bind to its cognate receptor, the type I interferon receptor (IFNAR), composed of heterodimeric receptor subunits known as IFNAR1 and IFNΑR2. The binding of type I interferon to receptors assists in the transduction of signals from the external to internal environments of cells to activate biological responses. In order to study the function of IFN, we first need to understand IFN receptors. In this study, we cloned and identified IFNAR1 in orange-spotted grouper (osgIFNAR1) and noted the up-regulated mRNA expression of the receptor and downstream effectors in the head kidney cells with cytokine treatment. The transcriptional expression of osgIFNAR1, which is characterised using polyinosinic-polycytidylic acid (poly[I:C]) and lipopolysaccharide (LPS) treatments, indicated the involvement of osgIFNAR1 in the immune response of grouper. The subcellular localisation of osgIFNAR1 demonstrated scattering across the grouper cell. Viral infection showed the negative feedback regulation of osgIFNAR1 in grouper larvae. Further loss of function of IFNAR1 showed a decreased expression of the virus. This study reported the identification of osgIFNAR1 and characterisation of receptor sensitivity towards immunostimulants, cytokine response, and viral challenge in the interferon pathway of orange-spotted grouper and possible different role of the receptor in viral production. Together, these results provide a frontline report of the potential function of osgIFNAR1 in the innate immunity of teleost.

Advances in salmonid fish immunology: A review of methods and techniques for lymphoid tissue and peripheral blood leucocyte isolation and application

Evaluating studies over the past almost 40 years, this review outlines the current knowledge and research gaps in the use of isolated leucocytes in salmonid immunology understanding. This contribution focuses on the techniques used to isolate salmonid immune cells and popular immunological assays. The paper also analyses the use of leucocytes to demonstrate immunomodulation following dietary manipulation, exposure to physical and chemical stressors, effects of pathogens and parasites, vaccine design and application strategies assessment. We also present findings on development of fish immune cell lines and their potential uses in aquaculture immunology. The review recovered 114 studies, where discontinuous density gradient centrifugation (DDGC) with Percoll density gradient was the most popular leucocyte isolation method. Fish head kidney (HK) and peripheral blood (PB) were the main sources of leucocytes, from rainbow trout (Oncorhynchus mykiss) and Atlantic salmon (Salmo salar). Phagocytosis and respiratory burst were the most popular immunological assays. Studies used isolated leucocytes to demonstrate that dietary manipulations enhance fish immunity, while chemical and physical stressors suppress immunity. In addition, parasites, and microbial pathogens depress fish innate immunity and induce pro-inflammatory cytokine gene transcripts production, while vaccines enhance immunity. This review found 10 developed salmonid cell lines, mainly from S. salar and O. mykiss HK tissue, which require fish euthanisation to isolate. In the face of high costs involved with density gradient reagents, the application of hypotonic lysis in conjunction with mico-volume blood methods can potentially reduce research costs, time, and using nonlethal and ethically flexible approaches. Since the targeted literature review for this study retrieved no metabolomics study of leucocytes, indicates that this approach, together with traditional technics and novel flow cytometry could help open new opportunities for in vitro studies in aquaculture immunology and vaccinology.

Functional characterization of IL-10 and its receptor subunits in a perciform fish, the mandarin fish, Siniperca chuatsi

Interleukin (IL)-10 is an immune-regulatory cytokine with multiple functions. In the current study, IL-10 and its two receptors, IL-10R1 and IL-10R2 were identified in mandarin fish, Siniperca chuatsi. The inhibitory effect of mandarin fish IL-10 was investigated on pro-inflammatory cytokine expression and the ligand-receptor relationship. This IL-10 possesses conserved cysteine residues, predicted α-helices and a typical IL-10 family signature motif, similar to its mammalian orthologue, and IL-10R1 harbours predicted JAK1 and STAT3 binding sites in the intracellular region. The fish IL-10 and IL-10R1 exhibit high expression levels in several immune-related organs/tissues, such as spleen, trunk kidney and head kidney, and IL-10R2 possesses a constitutive expression pattern. The expression of IL-10 shows significant increase in spleen from infectious spleen and kidney necrosis virus (ISKNV) infected mandarin fish, where the two receptors also exhibit different levels of induced expression. Mandarin fish IL-10 also exhibits significant response to the stimulation of LPS, PHA and PMA, with the two receptors exhibiting an interesting decrease in expression following the treatment of PMA. The pro-inflammatory cytokines, IL-6, IL-1β, IL-8, TNF-α, show diminished up-regulation in LPS-stimulated splenocytes pre-incubated with IL-10, indicating the anti-inflammatory roles of mandarin fish IL-10. In EPC cells transfected with different combinations of receptors, IL-10 can enhance the expression of suppressor of cytokine signalling 3 (SOCS3) only when IL-10R1 and IL-10R2 are both expressed, suggesting the participation of the two receptors in signal transduction of mandarin fish IL-10. Similar results are observed with the usage of chimeric receptors, IL-10R1/CRFB1 and IL-10R2/CRFB5. Overall, mandarin fish IL-10 shares conserved ligand-receptor system and the prototypical inhibitory activities on pro-inflammatory cytokine expression with mammalian IL-10, implying the evolutionary conservation of this cytokine.

Molecular characterization and expression analysis of IL-22 and its two receptors genes in yellow catfish (Pelteobagrus filvidraco) in response to Edwardsiella ictaluri challenge

Interleukin (IL)-22, as a member of the interleukin (IL)-10 family, is an important mediator between the immune cells and epithelial tissues during infection and inflammation. This study reported the characterization and mRNA expression patterns of Pf_IL-22 gene and its cell surface-associated receptors Pf_IL-22RA1 and soluble Pf_IL-22RA2 genes in yellow catfish (Pelteobagrus filvidraco). The open reading frames (ORFs) of the Pf_IL-22, Pf_IL-22RA1 and Pf_IL-22RA2 genes were 546 bp, 1740 bp and 690 bp in length, encoding 181, 579 and 229 amino acids, respectively. Alignments of the deduced amino acid sequences present that the Pf_IL-22 has a conserved IL-10 family signature motif, and the Pf_IL-22RA1 and Pf_IL-22RA2 have two conserved fibronectin type-III domains. Quantitative real-time PCR (qPCR) analyses showed that the Pf_IL-22 and Pf_IL-22RA1 mRNAs were highly expressed in mucosal tissues such as the fin, gill, intestine, skin mucus and stomach, and were weakly expressed in the kidney, liver and head kidney of adult yellow catfish, indicating that the Pf_IL-22 transcripts may be mainly produced by mucosal immune cells/tissues in healthy yellow catfish. The mRNA expression levels of the Pf_IL-22RA2 gene were high in the muscle and liver, and were relatively low in the spleen and kidney. The mRNA expression levels of the Pf_IL-22 and its two receptor genes were significantly up-regulated in both mucosal tissues (gill, hindgut, and skin mucus) and systemic immune tissues (spleen, head kidney and blood) after Edwardsiella ictaluri challenge. These results indicated that the Pf_IL-22 and its two receptors genes might play an important role in the innate immune defense against bacterial invasion.

Cepeginterferon alfa-2b in the treatment of chronic myeloproliferative diseases

Purpose of the study. A comparative evaluation of the effectiveness of different therapeutic strategies in patients with polycythemia vera (PV) and essential thrombocythemia (ET). Materials and methods. Patients with PV or ET, diagnosed according to the criteria WHO 2016 were included in the study. The primary endpoint - 6 months of therapy (clinical-hematological and molecular responses). The secondary endpoint - 12 months of therapy (clinico-hematologic, molecular, histological responses). Sixty three patients were included in the analysis: the first group consisted of 33 patients who received the therapy with ce-pegiterferone alpha-2b (ce-pegalpha-INF-α-2b), 10 of them received previous treatment; the second group - 23 patients btained hydroxycarbamide; the third group - 7 patients were treated with recombinant interferon alpha therapy (rINFα). In comparison groups, differences in age were revealed: patients receiving hydroxycarbamide therapy were older. Phlebotomy occurred in 36% of patients in the first group, 9% in the second group, and 14% in the third group. Results. By the 6th month of therapy, 43% of the patients receiving the ce-pegalpha-INF-α-2b had complete clinical-hematologic response, 36% had partial clinical-hematologic remission and stabilization of the disease was established in 21% cases. No disease progression occured. By the 12th month of therapy, statistically significant differences in terms of efficacy between the different therapeutic groups (p = 0.2462, Fisher's exact test). In all three groups, the allelic load of JAK2V617F decreased: from 50 to 19%, from 22.3 to 15.8%, from 50 to 7.19%, respectively. The lower the allele load positively correlated with better response to therapy, which was observed in all analyzed groups. Hematologic adverse events (AEs) were more frequently observed in patients receiving ce-pegalpha-INF-α-2b therapy. Local reactions developed on 3-7 days of therapy as a hyperemic macula at the injection site. Both these reactions and hair loss did not influence on patient’s condition. In the second group (patients with hydroxycarbamide therapy) there were changes in the skin and mucous membranes: dry skin, stomatitis, and in older patients new keratomas appeared. The flu-like syndrome was the most common adverse event associated with the therapy of ce-pegalpha-INF-α-2b, which fully relived during the first month of therapy. There was only one case with the flu-like syndrome we observed at the 11th month of therapy. As a rule, the biochemical blood test changes did not influence on patient’s condition, were mostly associated with dietary violations, had a tendency to self-resolution and did not require medical interventions. Serious AEs were reported in one case - pulmonary embolism in a patient treated with rINFα. The reasons for the therapy discontinue in group 1: toxic hepatitis, intolerance, by the request of the patient, inadequate efficacy of therapy; in group 2: skin toxicity, in group 3: thromboses. The conclusion. Treatment of ce-pegalpha-INF-α-2b in patients with PV and ET is highly effective - the most patients pbtained clinical and hematological responses. There were no statistically significant differences in these parameters in comparison with hydroxycarbamide and rINFα. The use of the ce-pegalpha-INF-α-2b had an acceptable safety profile. The estimated therapeutic dose should be calculated according to body weight. To reduce the frequency of hematologic AE, titration of the drug dose is required.

Mechanisms of Fish Macrophage Antimicrobial Immunity

Overcrowding conditions and temperatures shifts regularly manifest in large-scale infections of farmed fish, resulting in economic losses for the global aquaculture industries. Increased understanding of the functional mechanisms of fish antimicrobial host defenses is an important step forward in prevention of pathogen-induced morbidity and mortality in aquaculture setting. Like other vertebrates, macrophage-lineage cells are integral to fish immune responses and for this reason, much of the recent fish immunology research has focused on fish macrophage biology. These studies have revealed notable similarities as well as striking differences in the molecular strategies by which fish and higher vertebrates control their respective macrophage polarization and functionality. In this review, we address the current understanding of the biological mechanisms of teleost macrophage functional heterogeneity and immunity, focusing on the key cytokine regulators that control fish macrophage development and their antimicrobial armamentarium.

Monocyte/Macrophage: NK Cell Cooperation-Old Tools for New Functions

Monocyte/macrophage and natural killer (NK) cells are partners from a phylogenetic standpoint of innate immune system development and its evolutionary progressive interaction with adaptive immunity. The equally conservative ways of development and differentiation of both invertebrate hemocytes and vertebrate macrophages are reviewed. Evolutionary conserved molecules occurring in macrophage receptors and effectors have been inherited by vertebrates after their common ancestor with invertebrates. Cytolytic functions of mammalian NK cells, which are rooted in immune cells of invertebrates, although certain NK cell receptors (NKRs) are mammalian new events, are characterized. Broad heterogeneity of macrophage and NK cell phenotypes that depends on surrounding microenvironment conditions and expression profiles of specific receptors and activation mechanisms of both cell types are discussed. The particular tissue specificity of macrophages and NK cells, as well as their plasticity and mechanisms of their polarization to different functional subtypes have been underlined. The chapter summarized studies revealing the specific molecular mechanisms and regulation of NK cells and macrophages that enable their highly specific cross-cooperation. Attention is given to the evolving role of human monocyte/macrophage and NK cell interaction in pathogenesis of hypersensitivity reaction-based disorders, including autoimmunity, as well as in cancer surveillance and progression.

Biology of Bony Fish Macrophages

Macrophages are found across all vertebrate species, reside in virtually all animal tissues, and play critical roles in host protection and homeostasis. Various mechanisms determine and regulate the highly plastic functional phenotypes of macrophages, including antimicrobial host defenses (pro-inflammatory, M1-type), and resolution and repair functions (anti-inflammatory/regulatory, M2-type). The study of inflammatory macrophages in immune defense of teleosts has garnered much attention, and antimicrobial mechanisms of these cells have been extensively studied in various fish models. Intriguingly, both similarities and differences have been documented for the regulation of lower vertebrate macrophage antimicrobial defenses, as compared to what has been described in mammals. Advances in our understanding of the teleost macrophage M2 phenotypes likewise suggest functional conservation through similar and distinct regulatory strategies, compared to their mammalian counterparts. In this review, we discuss the current understanding of the molecular mechanisms governing teleost macrophage functional heterogeneity, including monopoetic development, classical macrophage inflammatory and antimicrobial responses as well as alternative macrophage polarization towards tissues repair and resolution of inflammation.