Developmental and comparative immunology最新文献

Norepinephrine (NE) is involved in regulating cytokine expression and phagocytosis of immune cells in the innate immunity of vertebrates. In the present study, the modulation mechanism of NE on the biosynthesis of TNFs in oyster granulocytes was explored. The transcripts of CgTNF-1, CgTNF-2 and CgTNF-3 were highly expressed in granulocytes, and they were significantly up-regulated after LPS stimulation, while down-regulated after NE treatment. The phagocytic rate and apoptosis index of oyster granulocytes were also triggered by LPS stimulation and suppressed by NE treatment. The mRNA expressions of CgMAPK14 and CgRelish were significantly induced after NE treatment, and the translocation of CgRelish from cytoplasm to nucleus was observed. The concentration of intracellular Ca²⁺ in granulocytes was significantly up-regulated upon NE incubation, and this trend reverted after the treatment with DOX (specific antagonist for NE receptor, CgA1AR-1). No obvious significance was observed in intracellular cAMP concentrations in the PBS, NE and NE + DOX groups. Once CgA1AR-1 was blocked by DOX, the mRNA expressions of CgMAPK14 and CgRelish were significantly inhibited, and the translocation of CgRelish from cytoplasm to nucleus was also dramatically suppressed, while the mRNA expression of CgTNF-1 and the apoptosis index increased significantly to the same level with those in LPS group, respectively. These results collectively suggested that NE modulated TNF expression in oyster granulocyte through A1AR-p38 MAPK-Relish signaling pathway.

Lambs harboring the Hb-AA β-globin haplotype present improved cell-mediated responses and increased resistance against Haemonchus contortus infection. The aim of the present study was to compare the effect of sex and β-globin haplotypes on specific humoral responses and phenotypes of resistance during H. contortus infection in Morada Nova sheep. As expected, females displayed stronger resistance during the first and second experimental challenges. Differential systemic humoral immune responses were observed comparing sex groups, in which higher levels of specific antibodies targeting 24 kDa excretory-secretory (ES24) protein of H. contortus of IgG and IgM antibodies were respectively observed as predominant isotypes in males and females. The IgM levels were significantly correlated with phenotypes of resistance, evaluated by packed cell volume and fecal egg counts. To our knowledge this is the first study reporting divergent humoral responses profiles to H. contortus infection between male and female sheep. The impact of β-globin haplotypes was less pronounced in females compared to males. Notably, only males showed significant weight differences across haplotypes, with Hb-AA lambs being the heaviest. Additionally, Hb-AA males had significantly higher PCV (indicating better red blood cell health) and lower FEC (indicating lower parasite burden). These findings suggest a more pronounced effect of β-globin polymorphisms on H. contortus infection in males, potentially due to their generally weaker resistance compared to females. This study highlights the importance of sex and β-globin haplotypes in shaping immune responses to H. contortus infection. Specifically, IgM antibodies targeting the ES24 protein appear to play a crucial role in host-parasite interactions and may hold promise for therapeutic development.

The California sea hare (Aplysia californica) is a model for age associated cognitive decline. Recent researched identified a novel nidovirus, Aplysia Abyssovirus 1, with broad tropism enriched in the Aplysia nervous system. This virus is ubiquitous in wild and maricultured, young and old animals without obvious pathology. Here we re-evaluated gene expression data from several previous studies to investigate differential expression in the nervous system and gill in response to virus and aging as well as the mutational spectrum observed in the viral sequences obtained from these datasets. Viral load and age were highly correlated, indicating persistent infection. Upregulated genes in response to virus were enriched for immune genes and signatures of ER and proteostatic stress, while downregulated genes were enriched for mitochondrial metabolism. Differential expression with respect to age suggested increased iron accumulation and decreased glycolysis, fatty acid metabolism, and proteasome function. Interaction of gene expression trends associated with viral infection and aging suggest that viral infection likely plays a role in aging in the Aplysia nervous system. Mutation analysis of viral RNA identified signatures suggesting ADAR and AID/APOBEC like deaminase act as part of Aplysia anti-viral defense.

Regulation of neuroimmune interactions varies across avian species. Little is presently known about the interplay between periphery and central nervous system (CNS) in parrots, birds sensitive to neuroinflammation. Here we investigated the systemic and CNS responses to dextran sulphate sodium (DSS)- and lipopolysaccharide (LPS)-induced subclinical acute peripheral inflammation in budgerigar (Melopsittacus undulatus). Three experimental treatment groups differing in DSS and LPS stimulation were compared to controls. Individuals treated with DSS showed significant histological intestinal damage. Through quantitative proteomics we described changes in plasma (PL) and cerebrospinal fluid (CSF) composition. In total, we identified 180 proteins in PL and 978 proteins in CSF, with moderate co-structure between the proteomes. Between treatments we detected differences in immune, coagulation and metabolic pathways. Proteomic variation was associated with the levels of pro-inflammatory cytokine mRNA expression in intestine and brain. Our findings shed light on systemic impacts of peripheral low-grade inflammation in birds.

CD83 is a costimulatory molecule of antigen-presenting cells (APCs) that plays an important role in eliciting adaptive responses. It is also a well-known surface protein on mature dendritic cells (DCs). Furthermore, monocytes have been reported to differentiate into macrophages and monocyte-derived dendritic cells, which play an important role in innate immunity. CD83 expression affects the activation and maturation of DCs and stimulates cell-mediated immune responses. This study aims to reveal the CD83 expression during monocyte differentiation in teleosts, and the CD83 homologs evolutionary relationship. This study found two distinct CD83 homologs (GbCD83 and GbCD83-L) in ginbuna crucian carp (Gb) and investigated the evolutionary relationship among GbCD83 homologs and other vertebrates and the gene and protein expression levels of the homologs during 4 days of monocyte culture. The phylogenetic tree showed that the two GbCD83 homologs are classified into two distinct branches. Interestingly, only ostariophysians (Gb, common carp, rohu, fathead minnow and channel catfish), but not neoteleosts, mammals, and others, have two CD83 homologs. Morphological observation and colony-stimulating factor-1 receptor (CSF-1R), CD83, CD80/86, and CCR7 gene expressions illustrated that there is a differentiation of monocytes isolated from peripheral blood leukocytes after 4 days. Specifically, gene expression and immunocytochemistry revealed that GbCD83 is mainly expressed on monocytes at the early stage of cell culture, whereas GbCD83-L is expressed in the latter stage. These findings provided the first evidence of differential expression of CD83 homologs during monocytes differentiation in teleost.

Interleukin (IL) 20 is a multifunctional cytokine and plays a vital role in regulating autoimmune diseases, inflammation, and immune responses. IL-20 homologs have been described in fish. However, due to the lack of antibodies, cellular sources and immunological functions of fish IL-20 in response to infections have not been fully characterized. In this study, a monoclonal antibody (mAb) was generated against the recombinant grass carp (Ctenopharyngodon idella) IL-20 protein and characterized by immunoblotting, immunofluorescent microscopy and flow cytometry. It was shown that the IL-20 mAb specifically recognized recombinant IL-20 proteins expressed in the E. coli cells and HEK293 cells. Using confocal microscopy, the IL-20⁺ cells were identified in the head kidney, gills and intestine of grass carp, and induced after infection with Aeromonas hydrophila. Moreover, the IL-20 protein was found to be secreted mainly by CD3γδ T cells which were located predominantly in the gill filaments and intestinal mucosa. Taken together, our results suggest that IL-20 producing T cells are required for the mucosal immunity against bacterial infection in fish.

Toll-like receptors (TLRs) are a family of pattern recognition receptors (PRRs) that recognize invading pathogens and activate downstream signaling pathways. The number of 10 Tolls is found in Litopenaeus vannamei but have not yet been identified as the corresponding Toll homologue of model animal. In this study, we predicted the three-dimensional (3D) structures of 10 LvTolls (LvToll1-10) with AlphaFold2 program. The per-residue local distance difference test (pLDDT) scores of LvTolls showed the predicted structure of LvTolls had high accuracy (pLDDT>70). By structural analysis, 3D structures of LvToll2 and LvToll3 had high similarity with Drosophila melanogaster Toll and Toll7, respectively. 3D structure of LvToll7 and LvToll10 were not similar to that of other LvTolls. Moreover, we also predicted that LvSpätzle4 had high structural similarity to DmSpätzle. There were 9 potential hydrogen bonds in LvToll2-LvSpätzle4 complex. Importantly, co-immunoprecipitation assay showed that LvToll2 could bind with LvSpätzle4. Collectively, this study provides new insight for researching invertebrate immunity by identifying the protein of model animal homologue.

Interferon regulatory factors (IRFs) are transcription factors involved in immune responses, such as pathogen response regulation, immune cell growth, and differentiation. IRFs are necessary for the synthesis of type I interferons through a signaling cascade when pathogen recognition receptors identify viral DNA or RNA. We discovered that irf3 is expressed in the early embryonic stages and in all immune organs of adult zebrafish. We demonstrated the antiviral immune mechanism of Irf3 against viral hemorrhagic septicemia virus (VHSV) using CRISPR/Cas9-mediated knockout zebrafish (irf3-KO). In this study, we used a truncated Irf3 protein, encoded by irf3 with a 10 bp deletion, for further investigation. Upon VHSV injection, irf3-KO zebrafish showed dose-dependent high and early mortality compared with zebrafish with the wild-type Irf3 protein (WT), confirming the antiviral activity of Irf3. Based on the results of expression analysis of downstream genes upon VHSV challenge, we inferred that Irf3 deficiency substantially affects the expression of ifnphi1 and ifnphi2. However, after 5 days post infection (dpi), ifnphi3 expression was not significantly altered in irf3-KO compared to that in WT, and irf7 transcription showed a considerable increase in irf3-KO after 5 dpi, indicating irf7's control over ifnphi3 expression. The significantly reduced expression of isg15, viperin, mxa, and mxb at 3 dpi also supported the effect of Irf3 deficiency on the antiviral activity in the early stage of infection. The higher mortality in irf3-KO zebrafish than in WT might be due to an increased inflammation and tissue damage that occurs in irf3-KO because of delayed immune response. Our results suggest that Irf3 plays a role in antiviral immunity of zebrafish by modulating critical immune signaling molecules and regulating antiviral immune genes.

Defensins are antimicrobial peptides involved in innate immunity, and gene number differs amongst eutherian mammals. Few studies have investigated defensins in marsupials, despite their potential involvement in immunological protection of altricial young. Here we use recently sequenced marsupial genomes and transcriptomes to annotate defensins in nine species across the marsupial family tree. We characterised 35 alpha and 286 beta defensins; gene number differed between species, although Dasyuromorphs had the largest repertoire. Defensins were encoded in three gene clusters within the genome, syntenic to eutherians, and were expressed in the pouch and mammary gland. Marsupial beta defensins were closely related to eutherians, however marsupial alpha defensins were more divergent. We identified marsupial orthologs of human DEFB3 and 6, and several marsupial-specific beta defensin lineages which may have novel functions. Marsupial predicted mature peptides were highly variable in length and sequence composition. We propose candidate peptides for future testing to elucidate the function of marsupial defensins.

Immune-priming occurs in insects after a prior pathogen exposure. However, its underlying mechanism in insects remains elusive. In the present work, immune-priming was detected in a lepidopteran insect, Spodoptera exigua. Specifically, a prior infection with a heat-killed pathogenic bacterium, Escherichia coli, led to increased survival upon the second infection of different pathogens. Plasma collected from larvae with the prior infection possessed the immune-priming factor(s) that significantly up-regulated cellular and humoral immune responses of naïve larvae. Our study also finds that variations in the timing of plasma collection for priming larvae resulted in distinct impacts on both cellular and humoral responses. However, when the active plasma exhibiting the immune-priming was heat-treated, it lost this priming activity, therefore suggesting that protein factor(s) play a role in this immune-priming. An immunofluorescence assay showed that the hemocytes collected from the immune-primed larvae highly reacted to a polyclonal antibody specific to a vertebrate lipocalin, apolipoprotein D (ApoD). Among 27 ApoD genes (Se-ApoD1 ∼ Se-ApoD27) of S. exigua, Se-ApoD3 was found to be highly induced during the immune-priming, in which it was shown to be expressed in hemocytes and fat body from a fluorescence in situ hybridization analysis. RNA interference of Se-ApoD3 expression significantly impaired the immune-priming of S. exigua larvae. Moreover, the inhibition of eicosanoid biosynthesis suppressed the immune-priming, in which treatment with a lipoxygenase (LOX) inhibitor—and not treatment with a cyclooxygenase inhibitor—suppressed immune-priming. Further, an addition of LOX product such as lipoxin A₄ or lipoxin B₄ significantly rescued the lost immune-priming activity. Taken together, these results suggest that a complex of ApoD3 and LOX product mediates the immune-priming activity of S. exigua.