Developmental & Comparative Immunology

Turbot (Scophthalmus maximus) is an important aquaculture species, but the genomic organization and expressed diversity of its antibody repertoire remain incompletely characterized. In this study, we annotated the immunoglobulin heavy chain (IGH) locus using the haplotype resolved fScoMax1.1 genome assembly, and we used this as a reference to profile the expressed turbot IgM, IgD and IgT repertoires in skin and spleen. The primary IGH locus was located on chromosome 19, spanned approximately 72 kb, and contained 25 IGHV genes, including 24 functional genes and one pseudogene, together with three IGHD, seven IGHJ and three IGHC genes corresponding to IgT, IgM and IgD. Comparison with the alternate fScoMax1.1 haplotype and a second turbot genome assembly showed conserved IGHD, IGHJ and IGHC content, whereas IGHV gene number differed among assemblies. High throughput 5RACE repertoire sequencing revealed isotype and tissue associated differences in expressed IGH diversity. IgM represented the dominant productive repertoire in both skin and spleen and showed the highest clonotypic diversity, particularly in spleen. IgD displayed an intermediate profile, whereas IgT was more enriched in skin and exhibited the strongest clonal restriction. IGHV subgroup usage was dominated by IGHV3 in IgM and IgD, whereas IgT showed a distinct profile characterized by preferential use of IGHV4, especially in skin. Gene level analysis further showed broad IGHV-IGHJ pairing in IgM and IgD, with preferential use IGHJ3 segment, while IgT sequences paired exclusively with IGHJT. Clonotype sharing between skin and spleen was isotype dependent, being strongest for IgT, intermediate for IgM, and negligible for IgD, suggesting that clonal expansion did not necessarily predict inter tissue trafficking. Together, these results provide a curated genomic and expressed repertoire framework for turbot IGH genes and reveal isotype specific organization of antibody diversity, with IgT displaying a particular repertoire pattern.

SARS-CoV-2 continues to pose a threat to humans as well as domestic and wild animals. The variability in severity of clinical signs, the zoonotic potential, and the host-specific response to infection contribute to the persistence of circulation of disease. In wildlife species white-tailed deer have been shown to be more permissive to infection than bovids. However, amongst bovids, American bison have shown a greater susceptibility than cattle. In this study we investigate the transcriptomic response to experimental SARS-CoV-2 infection in bison over time. Substantial numbers of differentially expressed genes were identified between pre- and 2, 5, 7, 14, and 21 days post-infection. KEGG and GO term analysis identified associations with immune response, inflammatory response, and viral infection including COVID-19. IPA analysis of the SARS coronavirus pathway highlighted differences in signaling at days 2 versus 21 post-infection. We additionally examined changes in the nasal microbiome of bison over the course of experimental infection, which suggested an increase in opportunity for secondary infection causing pathogens such as Mannheimia. Collectively this study presents a profile of bison transcriptomic response to SARS-CoV-2 infection and continues to expand our understanding of variation in host response. SummarySARS-CoV-2 remains a threat to humans, domestic animals, and wildlife. Among bovids, American bison show greater susceptibility than cattle. We characterized the bison transcriptomic response to experimental infection across six timepoints, identifying extensive differential gene expression associated with immune, inflammatory, and antiviral pathways. KEGG, GO, and IPA analyses revealed activation of coronavirus-related signaling and shifts between days 2 and 21. We additionally examined changes in the nasal microbiome of bison over the course of experimental infection, which suggested an increase in opportunity for secondary infection causing pathogens such as Mannheimia. The results refine understanding of host responses to SARS-CoV-2 in bison.

NLRP3 is a cytosolic pattern recognition receptor that controls the formation of an inflammasome, a multimolecular complex that cleaves the pro-inflammatory cytokines interleukin-1{beta} and interleukin-18 into their bioactive forms. NLRP3 has been widely assumed to be conserved across vertebrates, suggesting it plays an indispensable role within the vertebrate innate immune system. Here, we used gene synteny, phylogeny, and structural analysis to examine the evolutionary origins of NLRP3 in greater detail. Our analysis revealed that modern NLRP3, defined by gene synteny and structural features, is unique to the eutherian lineage. Non-eutherian NLRP genes do not share synteny with the eutherian NLRP3 locus and lack conservation of key features including disc forming residues, cage interfaces, and membrane binding regions. NLRP3s characteristic regulatory architecture therefore appears to have evolved after eutherians split from marsupials 160 million years ago. These findings have important implications for understanding the beneficial roles of NLRP3 signalling and suggest that enhanced regulatory control of NLRP3 activity arose in response to distinct aspects of eutherian physiology.

Naturally occurring variation in the bovine mannose receptor C-type 1 gene (MRC1) may shape macrophage responses to Mycobacterium (M.) bovis, a key driver of bovine tuberculosis (bTB). We identified four coding region SNPs in MRC1 across Bos taurus (Holstein Friesian, Brown Swiss) and Bos indicus (Boran, Sahiwal) cattle breeds, including a non-synonymous variant, rs380943118 (c.2963G>A; Ser988Asn) in C-type lectin-like domain (CTLD) 6, most prevalent in Sahiwal cattle. Structural modelling suggested that the S988N substitution, which is spatially separated from the monosaccharide binding site of CTLD4, might indirectly affect glycan binding, perhaps through a conformational change in the receptor. Monocyte-derived macrophages upregulated MR expression during differentiation, with heterozygous (G/A) animals showing higher MR expression and increased uptake of GFP-M. bovis BCG, although differences were not statistically significant. Anti-CD206 blockade did not inhibit BCG internalization, either indicating that this specific antibody did not bind to a CTLD involved in ligand binding or that MR is not the sole entry receptor. These results highlight naturally occurring MRC1 polymorphisms that may influence MR structure and macrophage function, providing a foundation for future studies to assess their role in bTB susceptibility.

The corticotropin-releasing factor (CRF) system bidirectionally interacts with cytokines and other immune-related components in mammals. However, the nature of these interactions remains poorly characterized in other vertebrates, including teleost fishes. To gain insight into the relationship between immune responses and the CRF system in teleosts, we explored how CRF system components were transcriptionally regulated in immune organs of rainbow trout (Oncorhynchus mykiss). We first characterized the CRF system in the spleen and head kidney--two primary immune organs in teleosts--and found that many CRF system components were present in both tissues, but splenic expression was consistently greater. Changes in the abundance of splenic CRF system components following vaccination (which transiently stimulated inflammatory responses and cytokine production) indicated contrasting and time-dependent regulation of CRF receptor 1 (CRFR1; suppression) and CRFR2 (stimulation) activities in response to an inflammatory challenge. Using spleen explant cultures, we then evaluated whether these effects were mediated by either of nuclear factor kappa B (NF-{kappa}B; a pro-inflammatory transcription factor) or cortisol (an anti-inflammatory hormone). At baseline, cultured spleens increased cytokine production and exhibited transcriptional changes in CRF system components comparable to those observed following vaccination. Cortisol treatment and NF-{kappa}B inhibition both attenuated the rise in cytokine transcription; however, cortisol treatment generally affected transcripts influencing CRFR1 activity, while NF-{kappa}B inhibition reduced CRFR2 activity. Overall, our data provide novel insight into CRF system regulation in the spleen and suggest that cortisol and inflammatory cytokines differentially regulate CRFR1 and CRFR2 activity within this organ.

Cystic echinococcosis (CE), caused by the larval stage of Echinococcus granulosus, remains a significant public health and veterinary problem in endemic regions. Although chemotherapy and control programs exist, the development of complementary immunotherapeutic tools is increasingly needed. This study evaluated the generation and functional activity of hyperimmune serum (HIS) produced in three adult male castrated llamas (Lama glama) immunized with antigenic material derived from protoscoleces (PSCs) of the parasite. Sera collected after each of the first six immunizations were assessed by ELISA to quantify antigen-specific IgG responses, and their biological effects were tested in vitro using viable PSCs. Motility was measured using video-assisted paired-image scoring across serial serum dilutions (1:2-1:2048), and the methylene blue exclusion assay was used to assess viability. Hyperimmune serum produced a clear, reproducible, dose-dependent inhibition of PSC motility and viability. Higher titers of early inoculations reduced motility by 70-85%, while sera from the fifth and sixth inoculations achieved complete suppression. Naive serum and PBS controls showed no inhibitory effect. ELISA titers strongly correlated with biological activity, indicating that higher humoral responses predicted functional inhibition. These findings demonstrate the feasibility of generating potent anti-Echinococcus granulosus polyclonal antibodies in camelids and support their potential application in passive immunization strategies. The study establishes a foundation for future development of llama-derived immunobiological reagents, including nanobody-based tools, for the control of cystic echinococcosis.

Telomere length (TL) is increasingly used in ecology as a biomarker of individual quality and environmental stress, yet research on non-model species with complex life histories remains limited. Because TL varies among tissues and across ages in a species-specific manner, identifying non-lethal tissues that reliably reflect whole-organism telomere dynamics is essential for longitudinal telomere studies in the field. This study aimed to evaluate tissue-specific TL in Japanese eel (Anguilla japonica), an endangered catadromous fish. We first mapped the chromosomal distribution of telomeric sequences using fluorescent in situ hybridization (FISH), the first application of this method in this species. We then tested whether muscle and caudal fin, which can be sampled easily and non-lethally, can serve as suitable proxy tissues for TL measurements in wild individuals. Relative telomere length (RTL) was quantified by qPCR in blood, brain, caudal fin, gonads, heart, liver, and muscle. FISH analysis confirmed telomeric repeats at all chromosomal ends, with only weak interstitial signals on three chromosomal pairs unlikely to affect qPCR-based estimates. A generalized additive mixed model and Wilcoxons signed-rank tests revealed significant inter-tissue differences: RTL was shortest in the brain and muscle and longest in liver, blood and caudal fin. Muscle and caudal fin RTL were significantly correlated with RTL in many other tissues, supporting their use as proxy tissues for longitudinal TL monitoring, including responses to environmental variation. Both total length and age were tested as explanatory variables for RTL, and the model including total length showed a better fit than the age-based model. Non-linear relationships between RTL and total length observed in several tissues suggest physiological shifts associated with growth and sexual differentiation. Overall, these findings advance understanding of telomere dynamics in eels and establish muscle and caudal fin as suitable tissues for repeated, non-lethal TL assessment in ecological and conservation contexts.

Eurasian avian like H1N1 (EAavH1N1) and influenza D viruses (IDV) with their ongoing evolution and zoonotic potential are a serious threat to animal and human health. Using experimental infection of pigs, we characterized and compared their pathogenesis, and immune responses. EAavH1N1 induced rapid viral clearance, early immune activation, including robust systemic and mucosal antibody responses and increased IFN{gamma} and TNF production. This heightened immune response was associated with more severe pathology of the upper and lower respiratory tract. In contrast, IDV infection resulted in prolonged viral shedding and higher viral titres, with delayed and attenuated cellular immune responses. Single cell transcriptomic analysis of lung further indicated early and persistent suppression of antiviral and innate immune pathways during IDV infection. These findings demonstrate that EAavH1N1 and IDV exhibit distinct viral kinetics, immune activation profiles, and lung responses, providing insight into differences in transmission dynamics, disease severity, and immune control among influenza virus types in swine.

Black-footed ferrets (Mustela nigripes) are highly susceptible to sylvatic plague caused by Yersinia pestis, but the genetic basis of this vulnerability remains poorly understood. Here, comparative immunogenomic analyses across Carnivora species identified a conserved class of immunoglobulin lambda variable (IGLV) genes with unusually long antigen-binding sites (CDRL1) that are common among Caniformia species but absent in Feliformia species. First discovered in the domestic ferret (Mustela putorius furo), these genes encode tyrosine-rich and anionic motifs resembling the chemokine receptor CCR5 and contain experimentally validated sulfotyrosines previously associated with pathogen-interacting interfaces. Evolutionary analyses revealed distinct selective pressures across Caniformia lineages and showed strong purifying selection acting on long-CDRL1 IGLV genes in mustelids and bears. Antibody repertoire sequencing demonstrated that these genes are actively utilized in expressed repertoires and that their usage correlates with evolutionary conservation. Functional analyses of monoclonal antibodies derived from the long-CDRL1 IGLV gene identified an antibody that significantly reduced intracellular Y. pestis survival in macrophages and revealed a positive correlation between anti-plague activity and sulfotyrosine signal. Notably, all analyzed black-footed ferrets carried a frameshifting deletion in the long-CDRL1 IGLV gene resulting in loss of its expression in antibody repertoires. Together, these findings uncover a germline-encoded immunoglobulin feature conserved across dog-like carnivores and suggest a potential link between antibody germline variation and immune responses to plague.

The AMY2B gene encodes pancreatic amylase, a critical enzyme for starch digestion. While previous studies have examined AMY2B copy number variation (CNV) in domestic and some wild animals, less is known about wild carnivores inhabiting regions with limited anthropogenic starch exposure. We analyzed blood samples for serum amylase activity and copy number variation in AMY2B gene from 8 wolves (Canis lupus), 11 brown bears (Ursus arctos), and 3 red foxes (Vulpes vulpes) from Bosnia and Herzegovina. AMY2B gene copy number was assessed using droplet digital PCR (ddPCR), and serum amylase activity and glucose levels were quantified. Although the number of fox samples was limited, foxes and wolves consistently harbored two copies of AMY2B, while brown bears exhibited higher CNV (3.67-8.40, mean 5.88). Serum amylase activity was highest in foxes, moderate in wolves, and variable but lower in bears. Despite differences in AMY2B copy number and serum amylase activity, circulating glucose concentrations did not differ significantly among species. Our findings suggest that variation in AMY2B copy number among wild carnivores may be associated with species-specific evolutionary histories and dietary adaptations, providing insight into genomic mechanisms underlying carbohydrate utilization in natural populations.

The age at which Atlantic salmon reaches sexual maturity shows a strong hereditary component associated with the vgll3a locus. The role of Vgll3 in maturation has remained unknown in vertebrates until recently, when it has been linked to pleiotropic roles in killifish, both delaying male maturation and affecting lifespan by protecting against cancer. As Atlantic salmon has two vgll3 paralogs, where only vgll3a has been associated with sexual maturation, it may provide a suitable model for studying the maturation-specific function of vgll3, as the other paralog may buffer for pleiotropic roles of vgll3. To address this, we used CRISPR/Cas9 to generate fish highly mutated in the vgll3a gene. We monitored their maturation and crossed highly mutated crispants to generate two year-classes of complete loss-of-function. All groups were reared under environmental conditions triggering early maturation in one-year-old males. We found a clear difference in the proportion of sexually maturing or mature fish between the different genotypes: in all experiments significantly fewer vgll3a-/- males entered puberty and reached final maturation compared to vgll3a+/- and vgll3a+/+ males. Furthermore, loss of vgll3a resulted in lower frequencies of maturation also in females. We conclude that Vgll3a stimulates maturation and that its complete removal significantly reduced maturation rates in both sexes in Atlantic salmon. Our findings also identify vgll3a as the causative gene in the locus associated with age at sexual maturity. Together, our findings support a new role for Vgll3 in initiating puberty in vertebrates and identifying salmon as a promising model for functional studies regarding the timing of sexual maturation.

Detection of viral infection leads to both cell-intrinsic and cell-extrinsic responses. In mammals, cell-intrinsic detection of viral infection leads to cell-extrinsic activation of STAT (Signal Transduction and Activators of Transcription) proteins, a family of transcription factors that promote anti-viral defense. In the nematode C. elegans, STA-1/STAT is a negative regulator of anti-viral defense, but it is not known if it acts cell-intrinsically or cell-extrinsically and whether it has functional domains conserved with mammalian STATs. Here we show that C. elegans STA-1 protein disappears from nuclei of cells infected with the natural viral pathogen, Orsay virus, but remains nuclear in uninfected cells, indicating a cell-intrinsic site of action. During viral infection, STA-1 forms cytoplasmic puncta that interact with the RNA viral sensor DRH-1, suggesting that DRH-1 helps restrain this immune-repressive factor. STA-1 overexpression causes increased susceptibility to viral infection, in a manner dependent on conserved residues important for DNA binding, nuclear localization and phosphorylation. Structural predictions indicate that STA-1 is most similar to STAT5 proteins in mammals, which have known immune-repressive roles. Our transcriptomic analysis demonstrates that C. elegans STA-1 regulates a general anti-pathogen program, including genes upregulated later during viral infection. Altogether, our findings provide insight into conserved and distinct features of STA-1 in C. elegans, indicating an ancient role for cell-intrinsic, immune-repressive STATs. Author SummaryAll living organisms must detect viral infections and mount a defense to survive. One major antiviral defense pathway in mammals is the interferon response, which involves sensing viral infection in one cell, and delivering an interferon message to neighboring cells. These neighboring cells then turn on anti-viral defense gene expression using proteins called STAT transcription factors. We study anti-viral defense in the roundworm C. elegans, and in this study show that viral infected cells themselves use a STAT protein called STA-1, with perhaps a lesser role for STA-1 in neighboring cells, in contrast to mammals. We also extend on previous findings that STA-1 turns off anti-viral gene expression, and we analyze regions in the protein to demonstrate that STA-1 is bona fide transcription factor with an immune-repressive role. Structural prediction analysis of STA-1 indicates it is most similar to STAT5 in mammals, suggesting an ancient role for this protein as an immune-repressive factor acting directly in virally infected cells.

BackgroundSkeletal muscle growth is a key determinant of body size and market value in salmonid aquaculture, yet the mechanisms linking genomic variation to muscle fiber hypertrophy remain poorly resolved. Myofiber cross-sectional area (CSA) provides a quantitative cellular proxy for fiber size and a direct link to macroscopic growth traits. MethodsWe performed histological phenotyping of white skeletal muscle from rainbow trout (Oncorhynchus mykiss) representing divergent fillet-yield selection lines (ARS-FY-H and ARS-FY-L), quantifying mean myofiber CSA and fiber number using high-throughput image analysis. Genome-wide association analysis (GWAS) was conducted using low-pass whole-genome sequencing ([~]1x) with genotype imputation and functional variant annotation. RNA sequencing was performed on fish representing high and low CSA extremes to identify differentially expressed genes and enriched biological pathways. ResultsMean myofiber CSA was significantly associated with body weight, muscle weight, visceral weight, and body length (p < 0.05), while fiber count showed no significant association with most growth traits, implicating hypertrophy as the primary driver of muscle mass variation. GWAS identified a significant QTL spanning [~]4.76 Mb on chromosome 2 (117 significant SNPs; Bonferroni-adjusted P [&le;] 0.05; {lambda} = 1.02). Associated variants were predominantly noncoding, enriched in intronic, intergenic, and enhancer-annotated regions. A high density of SNPs colocalized with the TGF-{beta}2 locus, overlapping strong and genic enhancer elements in white muscle. Transcriptomic comparisons revealed that high-CSA muscle showed elevated expression of genes related to contractile function, cytoskeletal organization, and translation, while low-CSA muscle exhibited upregulation of extracellular matrix and immune-related genes consistent with a tissue remodeling state. ConclusionsNoncoding regulatory variation within a significant QTL spanning the TGF-{beta}2 locus is associated with distinct transcriptional programs linked to muscle fiber hypertrophy in rainbow trout. By integrating genetic variation, chromatin-state annotation, and transcriptomic profiling, this study identifies candidate regulatory loci associated with variation in muscle cellularity and growth-related phenotypes in rainbow trout.

The recent shift in Bangladesh from tradition backyard rearing system to modern commercial layer farming has made the birds immune to infectious diseases. Pediculosis, however, continues to pose a challenge in modern production system due to its invasive nature, often going unnoticed and neglected as it is typically non-lethal, yet capable of causing significant production losses. Lice infestation is a persistent threat in poultry production; however, its implications in battery-caged commercial layer hens in Bangladesh remain insufficiently characterized. The study aimed to identify the causative louse species and evaluate its associations with clinical pathology, hematological alteration and productive performance in 30 white-feathered (15 infested + 15 non-infested) and 30 brown-feathered (15 infested + 15 non-infested) laying birds from two commercial farms in Tangail. Morphological characterization confirmed the parasite as Menacanthus stamineus, distinguished by a dorsoventrally flattened body, parabolicallly rounded head wider than long, concealed club-shaped antennae, an oblong-oval abdomen with fine setae and three pairs of short legs each bearing paired claws. Infested birds exhibited consistent clinical pathology, including pale combs, petechial hemorrhages around the vent, severe feather damage with alopecic and exudative areas and incidence of irregular and broken-shelled eggs. Production performance analysis revealed significant reduction in hen-day egg production, egg weight, and feed intake, accompanied by significantly increased feed conversion ratios. Hematological evaluation demonstrated significantly reduced hemoglobin concentration, hematocrit and erythrocyte counts in infested hens, indicating mild anemia and compromised oxygen-carrying capacity. Collectively, pediculosis was strongly associated with lice-induced self-inflicted injury and cannibalism, systemic physiological stress, impaired erythropoiesis, reduced production efficiency and compromised welfare in caged laying hens. To best of our knowledge, it was the first integrative reports from Bangladesh documenting M. stramineus infestation in battery-caged commercial layer system with concurrent evidence of hematological disruption and measurable productivity losses, underscoring its epidemiological and economic significance and urgent need for targeted, evidence-based ectoparasite control strategies.

Avian influenza A viruses (IAV) pose a constant pandemic threat, with the recent 2.3.4.4b clade of the H5 subtype causing high pathogenicity and spreading across animal species and geographic locations. Understanding human pre-existing immunity to avian H5 IAV can inform on population susceptibility, a critical aspect of pandemic preparedness. To that end, we analysed the IAV HA-specific antibodies across individuals born between 1928-1999 with different early life exposures to IAV subtypes. Individuals born prior to 1957 had the highest pre-existing serum antibodies to group 1 HA antigens, including the 2.3.4.4b H5 and a group 1 HA stem antigen. These birth-year-specific patterns were not reflected in the limited pre-existing serum neutralising antibodies detectable against a 2.3.4.4b H5 IAV or in H5-specific memory B cell populations. They were however evident in pre-existing nasal IgG and IgA titres to H5, which were greater in individuals born prior to 1957. Our findings demonstrate that the immunological biases afforded by early life exposure extend to antibodies detected in the nasal mucosa, the site of IAV replication. ImportanceUnderstating pre-existing immunity to influenza A viruses of pandemic potential is an important aspect of pandemic preparedness. This includes an understanding the heterogeneity of pre-existing immunity across the population. Here, we demonstrate that pre-existing antibodies to H5 IAV vary according to year of birth and childhood imprinting. We demonstrate that this is the case for both systemic and nasal antibodies, highlighting the importance of understanding pre-existing mucosal immunity at the sites of influenza virus replication.

Hypoxia and anoxia are known to suppress cell proliferation due to an increase in replication stress and activation of DNA damage checkpoints. Embryos of the annual killifish Austrofundulus limnaeus show a strong tolerance to extended anoxic exposure, indicating an improved genomic stability under oxygen starvation. Here we investigate the cell cycle regulation of the anoxia tolerant killifish embryonic cell line PSU-AL-WS40NE during anoxic exposure. Live cell imaging confirms continued cell proliferation of WS40NE cells for the first 24 hours of anoxic exposure with minimal cell death. Fluorescent imaging shows that cells begin to accumulate in G1 after the first day in anoxia with a pronounced and rapid entry into the S phase upon reoxygenation. Pharmacological inhibition tests show that this response appears to be reliant more on ATR signaling then ATM, suggesting that increased {gamma}H2AX levels are driven by increased replication stress instead of DNA damage. This conclusion is further supported by an apparent lack of induction of a G2 checkpoint in these cells suggesting that DNA damage during anoxic replication is minimal. Maintaining cellular proliferation during initial exposure to anoxia and accumulating cells in the G1 phase for extended anoxic exposure is likely one way that embryos of the annual killifish are able to survive prolonged anoxia and provides insight into mechanisms that enable cells to proliferate under metabolic stress.

Abstract Background: The Chikungunya virus (CHIKV), a re-emerging mosquito-borne alphavirus, is responsible for acute febrile illness and severe polyarthralgia. Although both innate and adaptive immune responses influence the disease outcomes, the detailed cellular immunopathogenesis of CHIKV in peripheral blood is not yet fully elucidated. Methods: We conducted single-cell RNA sequencing (scRNA-seq) on peripheral blood mononuclear cells (PBMCs) obtained from patients acutely infected with CHIKV and from healthy control subjects. Cellular interactions were inferred, and the transcriptomic results were orthogonally validated through quantitative real-time PCR (qPCR) and Enzyme-Linked Immunosorbent Assay (ELISA) to assess systemic interferon-stimulated responses. Furthermore, a comparative analysis was performed using publicly available single-cell data from Dengue virus (DENV) infections. Results: CHIKV infection significantly altered the immune system, increasing monocytes and dendritic cells while reducing T and B lymphocytes. Monocytes and NK cells showed strong activation of interferon-stimulated genes (ISGs). Monocytes were identified as key in driving inflammatory and immune responses. In adaptive immunity, CHIKV led B cells to become plasmablasts with antiviral immunoglobulins and caused T cells and NK-like T cells to show signs of cytotoxicity and exhaustion. Validation showed increased levels of IFN-{gamma}, IFN-{beta}1, MX1, and ISG15. CHIKV triggered a more intense, monocyte-driven interferon response than DENV. Conclusions: Acute CHIKV infection induces a systemic interferon response predominantly centered on monocytes, accompanied by significant alterations in adaptive immunity. Circulating ISG products, including MX1 and ISG15, reflect the transcriptomic activation and may serve as potential biomarkers for assessing the early intensity of innate antiviral responses.

Pregnancy modulates the endometrial immune responses to establish maternal immune tolerance, and nuclear factor kappa B (NF-{kappa}B) subunits and I{kappa}B family are involved in the maternal innate and adaptive immune responses. It, nevertheless, is unclear if early pregnancy regulates the expression of NF-{kappa}B subunits and inhibitor of NF-{kappa}B (I{kappa}B) family in the ovine endometrium. In this study, ovine endometria were sampled at day 16 of the estrous cycle (N16), and at days 13, 16, and 25 of pregnancy (P13, P16, and P25), and mRNA and protein expression of NF-{kappa}B subunits and I{kappa}B family was analyzed by RT-qPCR, western blot, and immunohistochemistry. The results revealed that the expression of all NF-{kappa}B subunits was decreased at P25 compared with N16 both in mRNA and protein expression, but the expression of B cell leukemia-3, I{kappa}B, I{kappa}B kinase {gamma}, and I{kappa}B{delta} was increased at P25 compared with N16 both in mRNA and protein expression. I{kappa}B{beta}, however, was downregulated during early pregnancy, and the expression of I{kappa}B{varepsilon} and I{kappa}B{zeta} was decreased at P13 and P16 compared with N16 and P25 both in mRNA and protein expression. In summary, early pregnancy changed the expression of NF-{kappa}B subunits and I{kappa}B family in the ovine endometrium both in mRNA and protein expression, which may be essential for maternal immune tolerance and embryo implantation.

Artificial light at night (ALAN) disrupts natural light cycles and interferes with light-dependent biological processes. However, the effect of ALAN on cellular processes in wildlife is unclear. We examined diel brain transcriptomic alterations in the diurnal damselfish Dascyllus aruanus by comparing fish exposed to three consecutive nights of ALAN with control fish, sampled during both the day and night. ALAN partially disrupted circadian regulation transcription, altering diel expression of the core clock regulator bmal1 and glucocorticoid-regulated genes. At night, ALAN triggered activation of genes indicative of neuronal activity and acute neural stress, along with suppression of restorative nocturnal processes. The following day, the transcriptomic divergence between ALAN-exposed and control fish expanded, with widespread downregulation of genes governing vascular homeostasis, coagulation, and immune function. Together, these findings indicate that ALAN reshapes brain transcriptomic programs across the entire diel cycle, identifying molecular signatures of physiological disruption in light-polluted marine environments.

Entamoeba histolytica is a protozoan parasite that can cause severe liver disease known as amoebic liver abscess. However, only a subset of infected individuals develops invasive disease, indicating that host-parasite interactions are critical determinants of disease outcome. In this study, we investigated the clone-specific modulation of hepatic immune responses using non-pathogenic A1np and pathogenic B2p E. histolytica clones. Time-resolved transcriptome analyses (6, 12, 24 hours post-infection) in a murine model revealed distinct immune trajectories. Both clones activated innate immune pathways early after infection, but their responses differed markedly in magnitude and composition. A1np infection induced a rapid and controlled inflammatory response associated with antimicrobial activity and resolution-promoting signalling. In contrast, B2p infection triggered a stronger and more complex immune response characterised by pronounced cytokine and chemokine expression, activation of stress and redox pathways, and tissue remodelling processes. The B2p induced response exhibited features of excessive immune activation, accompanied by the upregulation of counter-regulation genes such as Ackr2. These findings indicate that liver pathology is not solely determined by parasite presence, but rather may also be influenced by the nature and regulation of the host immune response. Overall, the observed differences between A1np and B2p infections suggest that parasite-specific properties shape hepatic immune activation and may influence disease progression. Author summaryAlthough infection with the parasite Entamoeba histolytica can lead to severe liver disease, most infected individuals remain asymptomatic. This suggests that the outcome of the disease is not determined solely by the parasite, but also by how the host responds to the infection. In this study, we used a mouse model to compare how the liver reacts to infection with two E. histolytica clones that differ in their ability to cause amoebic liver abscesses. Using this model and time-resolved transcriptome analysis, we found that both clones trigger an early immune response; however, the nature of this response differs markedly. The non-pathogenic clone induced a rapid and controlled reaction associated with antimicrobial defence and tissue protection. In contrast, the pathogenic clone provoked a stronger and more prolonged inflammatory response accompanied by cellular stress and tissue remodelling processes. Notably, this heightened response also activated regulatory mechanisms that attempted to limit excessive inflammation. Our findings demonstrate that differences in disease severity are linked to the activation and regulation of the host immune system, rather than simply to the presence of the parasite.