Apoptosis, inflammatory and innate immune responses induced by infection with a novel goose astrovirus in goose embryonic kidney cells.

Introduction: Since 2016, a highly lethal visceral gout induced by infection with the novel goose astrovirus (GoAstV) resulted in an ongoing outbreak in goslings in China, with a mortality rate ranging from 10% to 50%, and causing considerable economic losses in the goose industry. However, the pathogenesis of GoAstV and the molecular mechanism by which kidney lesions are induced by GoAstV infection are unclear. Methods: In the present study, a GEK cell infection model for GoAstV was established, and the apoptosis, inflammatory and innate immune responses induced by GoAstV were investigated in GEK cells. Results: The results shown that the expression of proapoptotic proteins, including Bax, caspase-3, caspase-9 and cytochrome c, increased in the infection group; however, the expression of the antiapoptotic protein Bcl-2 decreased, indicating that apoptosis was induced by GoAstV infection in GEK cells. Besides, the activation of the RIG-I/MDA5 pathway and the downstream upregulation of proinflammatory cytokines, including the adapter proteins MAVS, IRF7 and NF-κB and the proinflammatory cytokines IL-6, IL-8 and TNF-α, were detected in GEK cells infected with GoAstV. In addition, GoAstV infection induces the activation of the NLPR3 pathway and further stimulates the increased production of IL-1ß. In summary, the present study revealed that GoAstV infection could induce apoptosis and the activation of the RIG-I/MDA5 and NLRP3 pathways in GEK cells, as well as the massive release of proinflammatory cytokines. Discussion: These results are helpful for elucidating the molecular mechanism of pathological lesions in the kidney in gout goslings infected with GoAstV and the interaction between GoAstV and the innate immune system of the host.

Goose surfactant protein A inhibits the growth of avian pathogenic Escherichia coli via an aggregation-dependent mechanism that decreases motility and increases membrane permeability.

Pulmonary collectins have been reported to bind carbohydrates on pathogens and inhibit infection by agglutination, neutralization, and opsonization. In this study, surfactant protein A (SP-A) was identified from goose lung and characterized at expression- and agglutination-functional levels. The deduced amino acid sequence of goose surfactant protein A (gSP-A) has two characteristic structures: a shorter, collagen-like region and a carbohydrate recognition domain. The latter contains two conserved motifs in its Ca2+-binding site: EPN (Glu-Pro-Asn) and WND (Trp-Asn-Asp). Expression analysis using qRT-PCR and fluorescence IHC revealed that gSP-A was highly expressed in the air sac and present in several other tissues, including the lung and trachea. We went on to produce recombinant gSP-A (RgSP-A) using a baculovirus/insect cell system and purified using a Ni2+ affinity column. A biological activity assay showed that all bacterial strains tested in this study were aggregated by RgSP-A, but only Escherichia coli AE17 (E. coli AE17, O2) and E. coli AE158 (O78) were susceptible to RgSP-A-mediated growth inhibition at 2-6 h. Moreover, the swarming motility of the two bacterial strains were weakened with increasing RgSP-A concentration, and their membrane permeability was compromised at 3 h, as determined by flow cytometry and laser confocal microscopy. Therefore, RgSP-A is capable of reducing bacterial viability of E. coli O2 and O78 via an aggregation-dependent mechanism which involves decreasing motility and increasing the bacterial membrane permeability. These data will facilitate detailed studies into the role of gSP-A in innate immune defense as well as for development of antibacterial agents.

Molecular cloning and functional studies on magang goose toll-like receptor 5.

Disease outbreaks heavily impact the economic viability of animal industries. Little is known about the mechanisms of immune system-related diseases in geese. Toll-like receptors (TLRs) play a major role in the anti-inflammatory immunity process in most animal species, but they have not been studied in the Magang goose. To elucidate the role of TLRs, reverse transcription polymerase chain reaction (RT-PCR) and PCR amplification of cDNA ends (Smart RACE) were used to clone the Magang goose TLR5 gene (mgTLR5). The full-length cDNA of mgTLR5 was 2967 bp in length, including a 5'-terminal untranslated region (UTR) of 215 bp, a 3'-terminal UTR of 384 bp, and an open reading frame of 2583 bp that encodes a protein of 860 amino acids. Structurally, mgTLR5 has a toll/interleukin-receptor (TIR) domain, a transmembrane domain, and seven leucine-rich repeats (LRRs) domains. Homology alignment of TLR5 and its TIR domains with other species revealed that mgTLR5 shared 98 % and 81.3 % of sequence similarity with white goose TLR5 and chicken TLR5, respectively. Quantitative RT-PCR showed that the mgTLR5 gene of the goose is widely expressed in all tested tissues, with the highest expression in the kidney and spleen. The increase in NF-κB promoter activity stimulated by flagellin was dependent on mgTLR5 expression in 293 T cells. Salmonella pullorum and flagellin significantly upregulated the expression of TLR5, IL-8, and IL-1 mRNA in peripheral blood mononucleotide cells of Magang goose cultured in vitro. Stimulation by S. pullorum for 24 h upregulated mgTLR5 expression in the cecum and kidney. We conclude that Magang goose TLR5 is a functional TLR5 homologue of the protein in other species and plays an important role in bacterial recognition.

The Antibacterial Activity of Erythrocytes From Goose (Anser domesticus) Can Be Associated With Phagocytosis and Respiratory Burst Generation.

In the lumen of blood vessels, there are large numbers of erythrocytes, which are approximately 95% of the total blood cells. Although the function of erythrocytes is to transport oxygen in the organism, recent studies have shown that mammalian and teleost erythrocytes are involved in the immune response against bacterial infections. However, the immune mechanisms used by avian erythrocytes are not yet clear. Here, we demonstrated that erythrocytes from goose have the ability to phagocytose as well as conduct antimicrobial activity. Firstly, we revealed the phagocytosis or adhesion activity of goose erythrocytes for latex beads 0.1-1.0 µm in diameter by fluorescence microscopy, and scanning and transmission electron microscopy. The low cytometry results also proved that goose erythrocytes had a wide range of phagocytic or adhesion activity for different bacteria. Followed, the low cytometry analysis data further explored that the goose erythrocytes contain the ability to produce reactive oxygen species (ROS) and inducible nitric oxide synthase (iNOS) in response to bacterial stimulation, and also up-regulated the expression of NOX family includes NOX1 and NOX5. Finally, we also found that goose erythrocytes showed a powerful antibacterial activity against all the three bacteria, meanwhile the stimulation of three kinds of bacteria up-regulated the expression of inflammatory factors, and increased the production of antioxidant enzymes to protect the cells from oxidative damage. Herein, our results demonstrate that goose Erythrocytes possess a certain phagocytic capacity and antioxidant system, and that the antimicrobial activity of erythrocytes can occurred through the production of unique respiratory burst against foreign pathogenic bacteria, which provides new clues to the interaction between bacteria and avian erythrocytes.

Comprehensive analysis of lncRNAs, miRNAs and mRNAs related to thymic development and involution in goose.

Thymic involution is a sign of immunosenescence, but little is known about it in goose. miRNAs and lncRNAs are critical factors regulating organ growth and development. In this study, we comprehensively analyzed the profiles of lncRNAs, miRNAs and mRNAs during the development and involution of the thymus in Magang goose. The results showed that 2436 genes, 16 miRNAs and 417 lncRNAs were differentially co-expressed between the developmental (20-embryo age, 3-day post-hatch and 3-month age) and degenerative (6-month age) stages. The functional analysis showed that these differentially expressed genes were significantly enriched in cell proliferation, cell adhesion, apoptotic signaling pathway, and Notch signaling pathway. In addition, we established a gene-gene network through the STRING database and identified 50 key genes. Finally, we constructed a miRNA-mRNA network followed by a lncRNA-miRNA-mRNA network. These results suggest that lncRNAs and miRNAs may be involved in the regulation of thymic development and involution in goose.

Increased immune marker variance in a population of invasive birds.

Immunity and parasites have been linked to the success of invasive species. Especially lower parasite burden in invasive populations has been suggested to enable a general downregulation of immune investment (Enemy Release and Evolution of Increased Competitive Ability Hypotheses). Simultaneously, keeping high immune competence towards potentially newly acquired parasites in the invasive range is essential to allow population growth. To investigate the variation of immune effectors of invasive species, we compared the mean and variance of multiple immune effectors in the context of parasite prevalence in an invasive and a native Egyptian goose (Alopochen aegyptiacus) population. Three of ten immune effectors measured showed higher variance in the invasive population. Mean levels were higher in the invasive population for three effectors but lower for eosinophil granulocytes. Parasite prevalence depended on the parasite taxa investigated. We suggest that variation of specific immune effectors, which may be important for invasion success, may lead to higher variance and enable invasive species to reduce the overall physiological cost of immunity while maintaining the ability to efficiently defend against novel parasites encountered.

Cross-Protection by Inactivated H5 Prepandemic Vaccine Seed Strains against Diverse Goose/Guangdong Lineage H5N1 Highly Pathogenic Avian Influenza Viruses.

The highly pathogenic avian influenza virus (HPAIV) H5N1 A/goose/Guangdong/1996 lineage (Gs/GD) is endemic in poultry across several countries in the world and has caused sporadic lethal infections in humans. Vaccines are important in HPAIV control both for poultry and in prepandemic preparedness for humans. This study assessed inactivated prepandemic vaccine strains in a One Health framework across human and agricultural and wildlife animal health, focusing on the genetic and antigenic diversity of field H5N1 Gs/GD viruses from the agricultural sector and assessing cross-protection in a chicken challenge model. Nearly half (47.92%) of the 48 combinations of vaccine and challenge viruses examined had bird protection of 80% or above. Most vaccinated groups had prolonged mean death times (MDT), and the virus-shedding titers were significantly lower than those of the sham-vaccinated group (P ≤ 0.05). The antibody titers in the prechallenge sera were not predictive of protection. Although vaccinated birds had higher titers of hemagglutination-inhibiting (HI) antibodies against the homologous vaccine antigen, most of them also had lower or no antibody titer against the challenge antigen. The comparison of all parameters and homologous or closely related vaccine and challenge viruses gave the best prediction of protection. Through additional analysis, we identified a pattern of epitope substitutions in the hemagglutinin (HA) of each challenge virus that impacted protection, regardless of the vaccine used. These changes were situated in the antigenic sites and/or reported epitopes associated with virus escape from antibody neutralization. As a result, this study highlights virus diversity, immune response complexity, and the importance of strain selection for vaccine development to control H5N1 HPAIV in the agricultural sector and for human prepandemic preparedness. We suggest that the engineering of specific antigenic sites can improve the immunogenicity of H5 vaccines.IMPORTANCE The sustained circulation of highly pathogenic avian influenza virus (HPAIV) H5N1 A/goose/Guangdong/1996 (Gs/GD) lineage in the agricultural sector and some wild birds has led to the evolution and selection of distinct viral lineages involved in escape from vaccine protection. Our results using inactivated vaccine candidates from the human pandemic preparedness program in a chicken challenge model identified critical antigenic conformational epitopes on H5 hemagglutinin (HA) from different clades that were associated with antibody recognition and escape. Even though other investigators have reported epitope mapping in the H5 HA, much of this information pertains to epitopes reactive to mouse antibodies. Our findings validate changes in antigenic epitopes of HA associated with virus escape from antibody neutralization in chickens, which has direct relevance to field protection and virus evolution. Therefore, knowledge of these immunodominant regions is essential to proactively develop diagnostic tests, improve surveillance platforms to monitor AIV outbreaks, and design more efficient and broad-spectrum agricultural and human prepandemic vaccines.

Avian anti-NS1 IgY antibodies neutralize dengue virus infection and protect against lethal dengue virus challenge.

Dengue is the most prevalent arboviral disease in humans and a continually increasing global public health burden. To date, there are no approved antiviral therapies against dengue virus (DENV) and the only licensed vaccine, Dengvaxia, is exclusively indicated for individuals with prior DENV infection. Endothelial hyperpermeability and vascular leak, pathogenic hallmarks of severe dengue disease, can be directly triggered by DENV non-structural protein 1 (NS1). As such, anti-NS1 antibodies can prevent NS1-triggered endothelial dysfunction in vitro and pathogenesis in vivo. Recently, goose-derived anti-DENV immunoglobulin Y (IgY) antibodies were shown to neutralize DENV and Zika virus (ZIKV) infection without adverse effects, such as antibody-dependent enhancement (ADE). In this study, we used egg yolks from DENV-immunized geese to purify IgY antibodies specific to DENV NS1 epitopes. We determined that 2 anti-NS1 IgY antibodies, NS1-1 and NS1-8, were capable of neutralizing DENV infection in vitro. In addition, these antibodies did not cross-react with the DENV Envelope (E) protein nor enhance DENV or ZIKV infection in vitro. Intriguingly, NS1-8, but not NS1-1, partially blocked NS1-induced endothelial dysfunction in vitro while neither antibody blocked binding of soluble NS1 to cells. Finally, prophylactic treatment of mice with NS1-8 conferred significant protection against lethal DENV challenge. Although further research is needed to define the mechanism of action of these antibodies, our findings highlight the potential of anti-NS1 IgY as a promising prophylactic approach against DENV infection.

Collocation of avian and mammal antibodies to develop a rapid and sensitive diagnostic tool for Russell's Vipers Snakebite.

Russell's vipers (RVs) envenoming is an important public health issue in South-East Asia. Disseminated intravascular coagulopathy, systemic bleeding, hemolysis, and acute renal injury are obvious problems that develop in most cases, and neuromuscular junction blocks are an additional problem caused by western RV snakebite. The complex presentations usually are an obstacle to early diagnosis and antivenom administration. Here, we tried to produce highly specific antibodies in goose yolks for use in a paper-based microfluidic diagnostic kit, immunochromatographic test of viper (ICT-Viper), to distinguish RVs from other vipers and even cobra snakebite in Asia. We used indirect ELISA to monitor specific goose IgY production and western blotting to illustrate the interaction of avian or mammal antibody with venom proteins. The ICT-Viper was tested not only in prepared samples but also in stored patient serum to demonstrate its preliminary efficacy. The results revealed that specific anti-Daboia russelii IgY could be raised in goose eggs effectively without inducing adverse effects. When it was collocated with horse anti-Daboia siamensis antibody, which broadly reacted with most of the venom proteins of both types of Russell's viper, the false cross-reactivity was reduced, and the test showed good performance. The limit of detection was reduced to 10 ng/ml in vitro, and the test showed good detection ability in clinical snake envenoming case samples. The ICT-Viper performed well and could be combined with a cobra venom detection kit (ICT-Cobra) to create a multiple detection strip (ICT-VC), which broadens its applications while maintaining its detection ability for snake envenomation identification. Nonetheless, the use of the ICT-Viper in the South-East Asia region is pending additional laboratory and field investigations and regional collaboration. We believe that the development of this practical diagnostic tool marks the beginning of positive efforts to face the global snakebite issue.

Effects of dietary supplementation of chitosan on immune function in growing Huoyan geese.

This present experiment was performed to investigate the effects of dietary supplementation of chitosan (CS) on immune function in growing Huoyan geese. A total of 320 28-day-old healthy growing Huoyan geese (sex balance) with similar body weight were randomly allotted into control, CS100, CS200, and CS400 groups. Each group includes 4 replicates with 20 geese per replicate, and the feeding trial lasted for 4 wk. The 4 diets contained 0, 100, 200, and 400 mg CS per kg feed, respectively. The results showed that compared with the control group, the relative weight of thymus, serum concentrations of IGF-I, INS, GH, T3, T4, IgM, IgG, IgA, complement C3, and IL-2 in CS200 group were significantly higher at both 42 and 56 D of age, respectively (P < 0.05). In addition, relative weight of bursa of fabricius (BF), spleen, serum complement C4, and TNF-a concentrations in CS200 group were higher at 56 D of age (P < 0.05), no differences were observed at 42 D of age (P > 0.05). These results indicated that addition of 200 mg/kg CS enhanced immune organs weight, serum concentrations of immunoglobulins, complements, hormone, as well as cytokines, and improved immune function of growing Huoyan geese.

Molecular cloning and functional analysis of TRAF6 from Yangzhou great white goose Anser anser.

TNF receptor-associated factor 6 (TRAF6) is an adaptor protein and an E3 ubiquitin ligase mediating multiple cell signaling pathway activation in a context-dependent manner. TRAF6 plays critical roles in innate immune response and regulates function of antigen-presenting cells. Here, we cloned the goose TRAF6 (goTRAF6) gene from a healthy Yangzhou great white goose (Anser anser), which had a typical TRAF structure and shared a high-sequence identity with TRAF6 of other birds. Quantitative real-time PCR revealed that goTRAF6 mRNA was broadly expressed in all the studied tissues, with highest expression in the heart and pectoral muscle. Overexpression of goTRAF6 caused NF-κB activation in a dose-dependent manner and substantially upregulated IFN-ß expression in HEK293T cells. Following Toll-like receptor (TLR) ligand stimulation of goose peripheral blood mononuclear cells, goTRAF6 and downstream inflammatory cytokine mRNA levels considerably up-regulated, especially at early stages. Salmonella Enteritidis challenge caused overexpression of goTRAF6 and cytokine mRNA in all the examined organs. These findings demonstrated that goTRAF6 played a substantial role in TLR-TRAF6 signaling cascade, and further contributed to the antibacterial-responses in host.

The role of active immunization against inhibin α-subunit on testicular development, testosterone concentration and relevant genes expressions in testis, hypothalamus and pituitary glands in Yangzhou goose ganders.

The present study was designed to investigate the potential role of immunization against inhibin on testicular development, plasma testosterone concentration and expression of relevant genes in hypothalamus, pituitary, Leydig and Sertoli cells in Yangzhou ganders. For this purpose, Yangzhou ganders, n = 30 were divided into groups A and B. Group B ganders were actively immunized against inhibin α-subunit, while group A ganders were immunized with bovine serum albumin (BSA), which served as control. Immunization against inhibin elevated testes weights. In addition, immunization against inhibin elevated GnRH, StAR, CYP11A1 and AMH mRNA transcription expressions as depicted by qRT-PCR. Furthermore, hypothalamic GnRH-I mRNA expressions were up regulated, while GnIH mRNA transcription expression showed reciprocal expression on day 227. LH-ß mRNA transcription expression remained unaffected. In conclusion, our findings suggest that active immunization against inhibin affect spermatogenesis and testicular development through regulations of hypothalamic, pituitary and testicular genes expressions.

Goose MAVS functions in RIG-I-mediated IFN-ß signaling activation.

Mitochondrial antiviral-signaling protein (MAVS) is an essential adaptor protein in retinoic acid-inducible gene I (RIG-I)-mediated antiviral innate immunity in mammals. In this study, the goose MAVS gene (goMAVS) was identified. The 2019 bp-long goMAVS exhibits 96.2% amino acid similarity compared to the predicted goMAVS. Quantitative real-time polymerase chain reactions showed that goMAVS mRNA was widely expressed in different tissues. The overexpression of goMAVS in goose embryo fibroblast cells up-regulated the mRNA levels of goose interferon-stimulated genes. We concluded that MAVS mediates the activation of type I interferon (IFN) pathway in a species-specific manner. We further demonstrated that a CARD-like domain, transmembrane domain and two previously unidentified domains of goMAVS were essential for the activation of type I IFN pathway. GoMAVS inhibited Newcastle disease virus replication by activating type I IFN pathways, especially at the early stages of infection. Finally, the interaction between goMAVS and goose RIG-I was confirmed. The CARD domain of goMAVS plays a vital role in the interaction. Together, we identified goMAVS as a goRIG-I interactive protein and concluded that goMAVS is involved in the activation of type I IFN pathways in goose cells.

Functional characterization of duck TBK1 in IFN-ß induction.

TRAF family member-associated NF-κB activator (TANK)-binding kinase 1 (TBK1) serves as hub molecule at the crossroad of multiple signaling pathways of type I interferon (IFN) induction. The importance of TBK1 in innate immunity has been demonstrated in mammalian, however the characterization and function of TBK1 in avian remains largely unknown. In this study, we cloned duck TBK1 (duTBK1) from duck embryo fibroblasts (DEFs) for the first time, which encoded 729 amino acids and had a high amino acid identity with goose and cormorant TBK1s. The duTBK1 showed a diffuse cytoplasmic localization in DEFs and was extensively expressed in all tested tissues. Overexpression of duTBK1 induced IFN-ß production through the activation of IRF1 and NF-κB in DEFs. The N-terminal kinase domain and the ubiquitin-like domain in middle of duTBK1 played pivotal roles in IFN-ß induction as well as in IRF1 and NF-κB activation. Furthermore, knockdown of duTBK1 by small interfering RNA significantly decreased poly(I:C)- or Sendai virus (SeV)-induced IFN-ß expression. In addition, duTBK1 expression dramatically reduced the replication of both duck reovirus (DRV) and duck Tembusu virus (DTMUV) in DEFs. These results suggested that the duTBK1 played a pivotal role in mediating duck antiviral innate immunity.

Evolutional conservation of molecular structure and antiviral function of a type I interferon, IFN-kappa, in poultry.

IFN-kappa (IFN-κ) is a type I IFN expressed by keratinocytes, monocytes and dendritic cells with important roles during the innate immune response period. This research was conducted to elaborate the evolution and characteristics of IFN-κ in poultry. Chicken IFN-κ is located on the sex-determining Z chromosome, which is greatly different from mammals. Poultry IFN-κ cluster together in a species-specific manner through positive selection pressure and share only 19-33% homology with mammalian IFN-κ and poultry other type I IFN. Both chicken and duck IFN-κ was constitutively expressed in spleen, skin, lung, and peripheral blood mononuclear cells (PBMC), as well as being significantly induced after treatment with virus in PBMC. Biologically, poultry IFN-κ has antiviral activity against VSV in chicken embryonic fibroblasts and duck embryonic fibroblasts (CEF and DEF) cells, and induces the expression of IFN stimulated genes (ISGs). After treatment with JAK1 inhibitor, the ISGs expression can be down-regulated. Overall, our research on poultry IFN-κ not only enriches the knowledge about IFN-κ but also facilitates further research on the role of type I IFNs in antiviral defense responses in poultry.

Development and application of a monoclonal antibody-based blocking ELISA for detection of antibodies to Tembusu virus in multiple poultry species.

BACKGROUND: Tembusu virus (TMUV) is a member of the genus Flavivirus. Outbreak of this virus infection in duck flocks was first observed in China in April 2010, causing severe egg drop and neurological signs in laying ducks. Recently reported duck infections in southeastern Asia highlighted the need for well-validated diagnostic methods of TMUV surveillance to understand its epidemiological characteristics and maintenance in nature. Several enzyme-linked immunosorbent assays (ELISAs) for the detection of TMUV infection have been reported, but none have been applied to high-throughput diagnostics. RESULTS: In this study, a monoclonal antibody (MAb) against TMUV was generated and characterized. MAb 9E4 was shown to bind specifically to a disulfide bond-dependent epitope on the domain I/II of TMUV E protein, and a blocking ELISA was established based on this MAb. The cut-off percentage inhibition value for negative sera was set at 30%. By comparison with the virus neutralization test, the specificity and sensitivity of the blocking ELISA were 96.37% and 100%, respectively, and the kappa value was 0.966, based on 416 serum samples collected from both experimentally and clinically infected ducks, geese and chickens. A good correlation (r2 = 07998, P < 0.001) was observed between the blocking ELISA and plaque reduction neutralization test (PRNT) titers. Using archived duck serum samples collected between 2009 and 2015, the seroprevalence in duck flocks raised in Northern China was estimated by blocking ELISA. CONCLUSIONS: Our MAb-based blocking ELISA provides a reliable and rapid diagnostic tool for serological monitoring of TMUV infection and evaluation of immune status following TMUV vaccination in multiple poultry species.

Goose toll-like receptor 3 (TLR3) mediated IFN-γ and IL-6 in anti-H5N1 avian influenza virus response.

Induction of the innate immune pathways is critical for early anti-viral defense. How geese recognize viral molecules and activate these pathways is not well understood. In mammals, Toll-like receptor 3 (TLR3) recognizes double-stranded RNA. Activation of TLR3 induces the activation of NF-кB and the production of type-I interferon. In this study, the goose TLR3 gene was cloned using rapid amplification of cDNA ends. Goose TLR3 encoded an 896-amino-acid protein, containing a signal secretion peptide, 14 extracellular leucine-rich repeat domains, a transmembrane domain, a Toll/interleukin-1 receptor signaling domain, and shared 46.7-84.4% homology with other species. Tissue expression of goose TLR3 varied markedly and was highest in the pancreas and lowest in the skin. Human embryonic kidney 293 cells transfected with goose TLR3 and NF-κB-luciferase-containing plasmids responded significantly to poly i:c. The expression of TLR3, IL-6 and IFN-γ mRNA, but not IL-1 mRNA, was significantly upregulated after poly i:c or high pathogenic avian influenza virus (H5N1) stimulation in goose peripheral blood mononuclear cells cultured in vitro. Furthermore, geese infected with H5N1 showed significant upregulation of TLR3, especially in the lung and brain. We conclude that goose TLR3 is a functional TLR3 homologue of the protein in other species and plays an important role in virus recognition.

Molecular identification of goose (Anser cygnoide) suppressor ubiquitin-specific protease 18 (USP18) and the effects of goose IFN and TMUV on its comparative transcripts.

Ubiquitin-specific protease 18 (USP18) is known as an inhibition factor and has been associated with the innate immune response to pathogens. USP18 is the only deconjugating protease with specificity for interferon-stimulated gene 15 (ISG15), which is supposed to be missing in birds. To analyze the efficacy of goose USP18 (goUSP18) against Tembusu virus (TMUV) infection, we first cloned USP18 homologous cDNA from TMUV infected geese. The coding sequence was 1131 bp, and the deduced amino acid sequence shared conserved motifs with its homologues. Tissue-specific expression has shown that goUSP18 transcripts are strongly expressed in the spleen and liver of adult geese, as well as in the pancreas of goslings. Moreover, the goUSP18 transcripts were induced by goose interferons (goIFN) in goose embryo fibroblasts (GEF) and by TLR ligands in peripheral blood mononuclear cells (PBMC). Notably, goUSP18 transcripts were highly up-regulated by TMUV infection compared to the basal level in uninfected birds. Taken together, these results suggested that goUSP18 was involved in host innate immunity against TMUV infection.

Transcriptome profiling reveals the immune response of goose T cells under selenium stimuli.

The goose is an economically important poultry species and a principal natural host of avian viruses. This study aimed to determine the effects of selenium on the immune response of geese. Under selenium stimulation, gene expression profiling was investigated using transcriptome sequencing. The selenoproteins were promoted by selenium stimulation, while the heat shock proteins, interleukin and interferons were mainly down-regulated. After comparison, 2228 differentially expressed genes were primarily involved in immune and environmental response, and infectious disease and genetic information processing related pathways were identified. Specifically, the enzymes of the lysosomes which acted as a safeguard in preventing pathogens were mostly up-regulated and six randomly selected differentially expressed genes were validated by quantitative polymerase chain reaction. In addition, the most proportional increased transcription factor family basic helix-loop-helix (bHLH) located in the 5' flank of selenoprotein P-like protein for selenium metabolism was identified by response to the selenium stimulation in this study. These analyses show that selenium can promote immune function by activating selenoproteins, transcript factors and lysosome pathway related genes, while weakening cytokine content genes in geese.