Porcine parvovirus 6 (PPV6) is an emerging virus whose epidemiology and clinical significance in China remain poorly defined. This study investigated the prevalence and genetic characteristics of PPV6 in Guangxi Province, China, using 497 porcine serum samples collected between 2015 and 2019. The overall PPV6 prevalence was 12.5% (62/497), with regional rates ranging from 12.0 to 17.6%. A high frequency of co-infection with porcine circoviruses (PCVs) was detected, with 46.8, 19.4, and 3.2% of PPV6-positive samples were also positive for PCV2, PCV3, and PCV4, respectively. To the best of our knowledge, this study describes the first reported detection of PPV6 and PCV4 co-infection. Ten complete PPV6 genomes were successfully sequenced and grouped into two sizes, 6,112 and 6,111 nt, the latter resulting from a single thymine deletion in the 3’ untranslated region (UTR). Phylogenetic analysis based on VP1 sequences classified global PPV6 strains into two distinct lineages (A and B). All strains identified in this study clustered within Group B. Conversely, three previously reported Chinese strains belonged to Group A. Fourteen amino acid substitutions in VP1 were strongly associated with this phylogenetic separation. Selection pressure analysis further identified multiple positively selected sites within the capsid protein. Overall, these findings advance understanding of the molecular epidemiology of PPV6 in southern China and highlight its potential interaction with PCVs, providing a basis for future investigations into viral pathogenesis and vaccine development.

Chicken gastrointestinal virome comprises a complex and diverse viral community with significant implications for host health and microbiome function. We analyzed 3,312 publicly available chicken gut metagenomic datasets to establish the chicken gastrointestinal virome collection (CGVD), which includes 39,380 non-redundant viral operational taxonomic units (vOTUs); notably, 84.90% (33,433/39,380) represent novel sequences absent from current databases. Over half of the CGVD vOTUs were classified as bacteriophages, predominantly from the order Caudovirales. The predicted hosts were mainly prokaryotes, particularly Bacillota and Bacteroidota, revealing a multifaceted landscape of virus-host interactions. Many vOTUs infected multiple bacterial phyla, indicating high adaptability and broad ecological impact. In addition, lifestyle prediction showed that 28.28% (11,137 /39,380) of the vOTUs in CGVD were identified as lytic phages. Functional annotation demonstrated that viral genes contribute to key metabolic processes, including nucleotide and amino acid metabolism, thereby facilitating viral replication and host adaptation. The detection of auxiliary metabolic genes and carbohydrate-active enzymes underscores the role of viruses in modulating the gut microbiome. Although antibiotic resistance genes and mobile genetic elements were present, their contribution to horizontal gene transfer appears limited. Additionally, marked regional differences in virome composition were observed between the small and large intestines, particularly in the abundance of families such as Siphoviridae and Myoviridae. CGVD not only highlights the key role of viruses in shaping the chicken gut microbiome and influencing microbial dynamics and metabolic pathways, but also provides new resources and insights for future research. ### Competing Interest Statement The authors have declared no competing interest.

Glioblastoma multiforme (GBM), a highly malignant invasive brain tumor, is associated with poor prognosis and survival and lacks an effective cure. High expression of the human cytomegalovirus (HCMV) immediate early protein 1 (IE1) in GBM tissues is strongly associated with their malignant progression, presenting a novel target for therapeutic strategies. Here, the bioluminescence imaging technology revealed remarkable tumor shrinkage and improved survival rates in a mouse glioma model treated with HCMV IE1/IE1mut vaccine. In addition, immunofluorescence data demonstrated that the treated group exhibited significantly more and larger tertiary lymphoid structures (TLSs) than the untreated group. The presence of TLS was associated with enhanced T cell infiltration, and a large number of proliferating T cells were found in the treated group. Furthermore, the flow cytometry results showed that in the treatment group, cytotoxic T lymphocytes exhibited partial polarization toward effector memory T cells and were activated to play a lethal role in the peripheral immunological organs. Furthermore, a substantial proportion of B cells in the draining lymph nodes expressed CD40 and CD86. Surprisingly, quantitative polymerase chain reaction indicated that a high expression of cytokines, including chemokines in brain tumors and immune tissues, induced the differentiation, development, and chemokine migration of immune cells in the treated group. Our study data demonstrate that IE1 or IE1mut vaccination has a favorable effect in glioma mice models. This study holds substantial implications for identifying new and effective therapeutic targets within GBM.

PCV2 and PRRSV are involved in a variety of disease syndromes, collectively referred to as Porcine Circovirus Associated Disease (PCVAD) and Porcine Respiratory Disease Complex (PRDC). To explore the effects of other pathogens on porcine PCVAD and PRDC. This study firstly conducted an epidemiological investigation on PPV, confirmed the prevalence of PPV sub-types in China; We then determined that other pathogens were more common in POS-PCV2 (PCV2 positive other pathogen detection rate) than NEG-PCV2 (other pathogen detection rate PCV2 negative); however, in POS-PRRSV (PRRSV positive other pathogen detection rate), the detection rate was lower than that of NEG-PRRSV (other pathogens were negative for PRRSV). To study the effect of PPV2, PPV3, PPV4, PPV5, PPV6, PPV7, PRRSV, PCV2, PCV3, TTsuV1, and TTsuV2 co-infection on PCV2-associated disease (PCVAD) and porcine respiratory disease complex (PRDC), we used a logit-link and a generalized linear model (GLM) of the binomial error distribution and compute the predictions. PCV3 (P < 0.001***), PRRSV (P < 0.001***), and TTsuV2 (P < 0.001***) were predicted to be the most significant factors associated with PCV2 in PCVAD and PRDC, PCV2 (P < 0.001***), PCV3 (P < 0.001***) and TTsuV2 (P = 0.003**) were the most significant factors associated with PRRSV in PCVAD and PRDC. These findings determine that PPV2, PPV3, PPV4, PPV5, PPV6, PPV7, PRRSV, PCV2, PCV3, TTsuV1, and TTsuV2 viruses are statistically associated as co-infectors frequency with PCV2 in PRDC and PRRSV in PCVAD diseased pigs through logit-link and a generalized linear model (GLM) of the binomial error distribution.

Introduction: Porcine reproductive and respiratory syndrome virus (PRRSV) causes reproductive and respiratory diseases in sow herds and piglets. The emergence of ORF5 RFLP 1-7-4-like (NADC34-like) PRRSV strain in China has brought a new round of challenges to PRRSV prevention. Methods: In addition, recombinant adenovirus vaccine candidates against the newly emerged NADC34-like strain were constructed in the study; the immunogenicity of the vaccine was investigated in piglets. After inoculation with PRRSV recombinant adenovirus, specific antibodies, neutralizing antibodies, and levels of IFN-gamma and IL-4 cytokines were detected in serum. Results: Thirty-five days after immunization, the levels of IFN-gamma and IL-4 cytokines in the pac-Ad5-34-GP3, pac-Ad5-34-GP5, and pac-Ad5-34-GP35 experimental groups were significantly higher (p < 0.05) than those of the PBS and the adenovirus group. All vaccines can cause corresponding Th1 and Th2 immune responses based on animal experimental results. After the challenge, no obvious clinical symptoms were observed in the immune groups compared with the control group, vaccinated animals could reduce the occurrence of viremia, and the occurrence of viremia was alleviated, with no obvious pathological changes in the lungs, indicating that recombinant adenovirus vaccine could provide a good protective immunity and produce a good humoral and cellular immune response at the same time. Discussion: It shows that the recombinant adenovirus vaccine group has better protection against the virus. Provide vaccine reserve and theoretical support for the emergence of new PRRSV subtypes in China.

ABSTRACT Hyperuricemia has become the second most prevalent metabolic disease after diabetes, but the limitations of urate-lowering treatment (ULT) drugs and patient nonadherence make ULT far less successful. Thus, more ULT approaches urgently need to be explored. Uric acid-degrading bacteria have potential application value in ULT. In this study, we isolated 44XB T , a uric acid-degrading bacterium, from black-headed gull ( Chroicocephalus ridibundus ) feces. Using a polyphasic taxonomic approach, strain 44XB T was identified as a novel genus within the family Bacillaceae ; subsequently, the name Aciduricibacillus chroicocephali was proposed. Strain 44XB T had a unique uric acid-dependent phenotype and utilized uric acid and allantoin as the sole carbon and nitrogen sources, but not common carbon sources or complex media. In the genome, multiple copies of genes involved in uric acid metabolic pathway ( pucL , pucM , uraD , and allB ) were found. Six copies of pucL (encoding urate oxidase) were detected. Of these, five pucL copies were in a tandem arrangement and shared 70.42%–99.70% amino acid identity. In vivo experiments revealed that 44XB T reduced serum uric acid levels and attenuated kidney damage in hyperuricemic mice through uric acid catalysis in the gut and gut microbiota remodeling. In conclusion, our findings discover a strain for studying bacterial uric acid metabolism and may provide valuable insights into ULT. IMPORTANCE The increasing disease burden of hyperuricemia highlights the need for new therapeutic drugs and treatment strategies. Our study describes the developmental and application values of natural uric acid-degrading bacteria found in the gut of birds and broadened the source of bacteria with potential therapeutic value. Furthermore, the special physiology characteristics and genomic features of strain 44XB T are valuable for further study.

As a potential vectored vaccine, Newcastle disease virus (NDV) has been subject to various studies for vaccine development, while relatively little research has outlined the immunomodulatory effect of the virus in antigen presentation. To elucidate the key inhibitory factor in regulating the interaction of infected dendritic cells (DCs) and T cells, DCs were pretreated with the NDV vaccine strain LaSota as an inhibitor and stimulated with lipopolysaccharide (LPS) for further detection by enzyme-linked immunosorbent assay (ELISA), flow cytometry, immunoblotting, and quantitative real-time polymerase chain reaction (qRT-PCR). The results revealed that NDV infection resulted in the inhibition of interleukin (IL)-12p40 in DCs through a p38 mitogen-activated protein kinase (MAPK)-dependent manner, thus inhibiting the synthesis of IL-12p70, leading to the reduction in T cell proliferation and the secretion of interferon-γ (IFN-γ), tumor necrosis factor-α (TNF-α), and IL-6 induced by DCs. Consequently, downregulated cytokines accelerated the infection and viral transmission from DCs to T cells. Furthermore, several other strains of NDV also exhibited inhibitory activity. The current study reveals that NDV can modulate the intensity of the innate–adaptive immune cell crosstalk critically toward viral invasion improvement, highlighting a novel mechanism of virus-induced immunosuppression and providing new perspectives on the improvement of NDV-vectored vaccine.

Atherosclerosis is still the main cause of death in developed and developing countries. Vascular smooth muscle cells (VSMCs) death disorder is a key pathogens of atherosclerosis. During the early stage of human cytomegalovirus (HCMV) infection, immediate early protein 2 (IE2) is critical in regulating its host cell death to ensure HCMV replication. Abnormal cell death induced by HCMV infection contributes to the development of numerous diseases, including atherosclerosis. Hitherto, the underlying mechanism of HCMV involved in the progression of atherosclerosis is still unclear. In this study, the infection models in vitro and in vivo were constructed to explore the pathogenesis of HCMV-related atherosclerosis. Our results indicated that HCMV could contribute to the progression of atherosclerosis by enhancing the proliferation, invasion, and inhibiting the pyroptosis of VSMCs under inflammatory conditions. Meanwhile, IE2 played a key role in these events. Our present research revealed a novel pathogenesis of HCMV-related atherosclerosis, which might help develop new therapeutic strategies.

Osteoarthritis (OA), a degenerative disease, has many pathological factors, including oxidative stress (OS), endoplasmic reticulum (ER) stress, apoptosis, and extracellular matrix (ECM) degeneration. OS regulates the pathological progression of OA via mitochondrial dysfunction, and ER stress and by modulating the derivation and elimination of reactive oxygen species (ROS). Though. 4-octyl itaconate (4-OI) is known for its effects on the treatment of various diseases, how it affects OA and its underlying mechanism still needs to be elucidated. Therefore, it is necessary to explore the effects of 4-OI both in vivo and in vitro. In our study, we used H2O2, which can accumulate ROS, OS and ER stress, to imitate the OA model in vitro. Using western blot, real-time quantitative reverse transcription polymerase chain reaction and immunofluorescence staining, we found that 125 μM 4-OI can inhibit apoptosis, ECM degeneration, mitochondrial dysfunction, ER stress and abundant accumulation of ROS in chondrocytes. We also showed that 4-OI can activate the Sirtuin1 gene (SIRT1). We used a SIRT1 inhibitor EX527 to identify the relationships among these pathological factors, and it showed that the 4-OI-mediated effect was achieved by promoting the SIRT1. In vivo, the bilateral medial meniscus was resected to establish the destabilization of the medial meniscus model wherein intraperitoneal injections of 2% and 5% 4-OI postponed the progression of OA. Collectively, this study confirmed that 4-OI can potentially impede the progression of OA by promoting the expression of SIRT1.

BackgroundWe have previously reported that human cytomegalovirus (HCMV) infection could promote the progression of glioma. Here we discovered a stress-induced nuclear protein ZC3H11A (ZC3) through high-throughput sequencing after HCMV infection, which has been reported recently by our research group in regulating mRNA export under stress conditions. And also, a thorough analysis of ZC3 in pan-cancer and the omics data of ZC3 are yet to be conducted.MethodsThe transcriptomes of glioma cells after HCMV infection were assessed by RNA sequencing. ZC3 mRNA and protein level following HCMV infection were validated and measured by qRT-PCR and Western-blot. The RNA sequencing and protein expression information of ZC3 across pan-cancer were analyzed and visualized by R packages. The localization of ZC3 protein was assessed by IHC images from HPA. The ZC3 proteomics and transcriptomics data in different cancers were extracted through the CPTAC data portal, and comparisons were conducted with a Python script. The genetic alteration, survival prognosis, immune infiltration analysis of ZC3 in pan-cancer were analyzed by cBioPortal, TCGA, and TIMER2 databases. The protein interaction networks were revealed by STRING, GEPIA2 and TCGA.ResultsGenes in mRNA processing pathways were upregulated after HCMV infection and ZC3 expression in mRNA and protein level was validated. We also discovered that the status of ZC3 were generally at high levels in cancers, although varied among different cancer types. ZC3 protein in tumor cells localized to the nuclear whereas in normal cells it was mainly found in cytoplasmic/membranous. However, from ZC3 proteomics and transcriptomics data in some cancer types, the increase in ZC3 protein was not accompanied by a significant elevation in mRNA level. Additionally, our analysis indicated that elevated ZC3 expression was primarily linked to a negative prognosis in majority cancers but still varied depending on the cancer types. Our annotation analysis suggested that ZC3-related proteins are mainly involved in mRNA processing clusters.ConclusionWe demonstrated that ZC3 significantly impacted by HCMV infection in gliomas. Furthermore, we identified a set of genes exhibiting analogous expression patterns to ZC3H11A in TCGA pan-cancer cohorts, implying a potential functional role for ZC3H11A in mRNA processing. Our study provided valuable insights into the role of a new mRNA export protein ZC3 in HCMV infection and pan-cancer progression. These results lay the foundation for our next research on the regulatory mechanism of ZC3 in virus-infected tumors.

ABSTRACTHuman cytomegalovirus (HCMV) infection is prevalent worldwide, and there is currently no licenced HCMV vaccine to control it. Therefore, developing an effective HCMV vaccine is a significant priority. Because of their excellent immunogenicity, the crucial components of HCMV, phosphoprotein 65 (pp65) and glycoproteins H (gH) are potential target proteins for HCMV vaccine design. In this study, we predicted and screened the dominant antigenic epitopes of B and T cells from pp65 and gH conjugated with the carrier protein cross-reacting material 197 (CRM197) to form three peptide-CRM197 vaccines (pp65-CRM197, gH-CRM197, and pp65-CRM197+gH-CRM197). Furthermore, the immunogenicity of the peptide-CRM197 vaccines and their effects on dendritic cells (DCs) were explored. The results showed that three peptide-CRM197 vaccines could induce maturation of DCs through the p38 MAPK signalling pathway and promote the release of proinflammatory factors, such as TNF-α and interleukin (IL) −6. Meanwhile, the peptide-CRM197 vaccines could effectively activate T cell and humoral immunity, which were far better than the inactivated HCMV vaccine. In conclusion, we constructed three peptide-CRM197 vaccines, which could induce multiple immune effects, providing a novel approach for HCMV vaccine design.

Since 2013, a dengue epidemic has broken out in Yunnan, China and neighboring countries. However, after the COVID-19 pandemic in 2019, the number of dengue cases decreased significantly. In this retrospective study, epidemiological and genetic diversity characterizations of dengue viruses (DENV) isolated in Yunnan between 2017 and 2018 were performed. The results showed that the dengue outbreak in Yunnan from 2017 to 2018 was mainly caused by DENV1 (genotype I and genotype V) and DENV2 (Asia I, Asia II, and Cosmopolitan). Furthermore, correlation analysis indicated a significant positive correlation between the number of imported and local cases (correlation coefficient = 0.936). Multiple sequence alignment and phylogenetic divergence analysis revealed that the local isolates are closely related to the isolates from Myanmar and Laos. Interestingly, recombination analysis found that the DENV1 and DENV2 isolates in this study had widespread intra-serotype recombination. Taken together, the results of the epidemiological investigation imply that the dengue outbreak in Yunnan was primarily due to imported cases. This study provides a new reference for further investigations on the prevalence and molecular epidemiology of DENV in Yunnan, China.

Platycodon grandiflorum (Jacq.) A. DC. is a famous medicinal plant commonly used in East Asia. Triterpene saponins isolated from P. grandiflorum are the main biologically active compounds, among which polygalacin D (PGD) has been reported to be an anti-tumor agent. However, its anti-tumor mechanism against hepatocellular carcinoma is unknown. This study aimed to explore the inhibitory effect of PGD in hepatocellular carcinoma cells and related mechanisms of action. We found that PGD exerted significant inhibitory effect on hepatocellular carcinoma cells through apoptosis and autophagy. Analysis of the expression of apoptosis-related proteins and autophagy-related proteins revealed that this phenomenon was attributed to the mitochondrial apoptosis and mitophagy pathways. Subsequently, using specific inhibitors, we found that apoptosis and autophagy had mutually reinforcing effects. In addition, further analysis of autophagy showed that PGD induced mitophagy by increasing BCL2 interacting protein 3 like (BNIP3L) levels.In vivo experiments demonstrated that PGD significantly inhibited tumor growth and increased the levels of apoptosis and autophagy in tumors. Overall, our findings showed that PGD induced cell death of hepatocellular carcinoma cells primarily through mitochondrial apoptosis and mitophagy pathways. Therefore, PGD can be used as an apoptosis and autophagy agonist in the research and development of antitumor agents.

Although multiple factors are known to concur with Alzheimer's disease (AD), the relationship between human cytomegalovirus (HCMV) and AD-like disease is unclear. Here, we propose a hypothesis that HCMV immediate-early 2 (IE2) protein promotes microglia activation and thus leads to AD-like disease. We successfully constructed IE2 transgenic mice expressing IE2 in the hippocampus. Single-cell sequencing analysis revealed that IE2 promoted the activation of microglia and upregulated the expression of disease-associated microglia genes. Differentially expressed gene analysis and pathway enrichment revealed that IE2 upregulated immune and nervous system disease-related genes. Immunohistochemical analysis showed that the expressions of both amyloid precursor protein (APP) and p-Tau were significantly upregulated in the brains of IE2 mice and were markers of AD. Taken together, these findings provide useful insights into AD-like disease activated by HCMV IE2.

Metabolic diseases are often associated with high fructose (HF) consumption. HF has also been found to alter the gut microbiota, which then favors the development of nonalcoholic fatty liver disease. However, the mechanisms underlying of the gut microbiota on this metabolic disturbance are yet to be determined. Thus, in this study, we further explored the effect the gut microbiota concerning the T cells balance in an HF diet mouse model. We fed mice 60% fructose-enriched diet for 12 weeks. At 4 weeks, HF diet did not affect the liver, but it caused injury to the intestine and adipose tissues. After 12 weeks, the lipid droplet aggregation was markedly increased in the liver of HF-fed mice. Further analysis of the gut microbial composition showed that HF decreased the Bacteroidetes/Firmicutes ratio and increased the levels of Blautia, Lachnoclostridium, and Oscillibacter. In addition, HF can increase the expression of pro-inflammatory cytokines (TNF-α, IL-6, and IL-1β) in the serum. T helper type 1 cells were significantly increased, and regulatory T(Treg) cells were markedly decreased in the mesenteric lymph nodes of the HF-fed mice. Furthermore, fecal microbiota transplantation alleviates systemic metabolic disorder by maintaining liver and intestinal immune homeostasis. Overall, our data indicated that intestinal structure injury and intestinal inflammation might be early, and liver inflammation and hepatic steatosis may be a subsequent effect following HF diets. Gut microbiota disorders impairing the intestinal barrier function and triggering immune homeostasis imbalance may be an importantly responsible for long-term HF diets induced hepatic steatosis.

Highly pathogenic porcine reproductive and respiratory syndrome(HP-PRRS)has been raging in China for a long time,domestic vaccines are mainly live attenuated vaccines,which can ef-fectively protect pigs from viruses,but are easy to recombine with wild strains,resulting in the e-mergence of new variants.Inactivated vaccines are safe but low vaccine titer,so this study is to de-velop a safe and effective vaccine that will not recombinant.Reverse genetic technology was used to insert HP-PRRSV antigenically active GP5 gene sequence into Newcastle disease virus vector.Re-combinant viruses that stably express GP5 was rescued,identified by PCR,enzyme digestion,Western blot,indirect immunofluorescence(IFA)and virulence detection experiments.The results showed that the D value of specific antibody at 35 d was 0.47(P＜0.01),and neutralizing antibody reached 1:8(P＜0.01),which could induce efficient antibody expression in mice.The proliferation of splenic lymphocytes in rL-GP5(LQ)group was significantly increased(P＜0.01),indicating that rL-GP5(LQ)could induce the immune response in vivo,providing new vaccine candidates and ideas for the prevention and control of HP-PRRS.

Lung cancer is a fatal disease with the highest worldwide morbidity and mortality rates. Despite recent advances in targeted therapy and immune checkpoint inhibitors for cancer, their efficacy remained limited. Therefore, we designed a Newcastle disease virus (NDV)-modified tumor whole-cell vaccine as a therapeutic vaccine and identified its antigen presentation level to develop effective immunotherapy. Then, we calculated the therapeutic and immune-stimulating effects of NDV-modified lung cancer cell vaccine and intratumoral NDV injection combination on tumor-bearing mice. The results showed that the immunogenic cell death (ICD) expression in NDV-modified lung cancer cell vaccine stimulates dendritic cell maturation and T cell activation in vivo and in vitro. Moreover, NDV-modified lung cancer cell vaccine combined with intratumoral NDV injection could significantly inhibit tumor growth and enhance the differentiation of Th1 cells and Inflammatory cell infiltration in vivo, leading to an excellent immunotherapeutic effect. Therefore, our results revealed that NDV-modified lung cancer cell vaccine combined with intratumoral NDV injection could promote antigen presentation and induce a strong antitumor immune response, which provided a promising combined therapy strategy for tumor immunotherapy.

Human cytomegalovirus (HCMV) infection is a major cause of neonatal neurodevelopmental disorders and serious complications in organ transplantation. Previous HCMV vaccines focused on humoral immunity but had limited effect on viral infection. T-cell responses are essential to prevent HCMV infection, indicating that effective vaccines require T cells activation. In this study, we designed a novel polypeptides vaccine conjugated to a CRM197 carrier protein, encoding 15 CD8+ T-cell epitopes, five CD4+ T-cell epitopes, and four B-cell epi-topes from gB287-320 and pp150311-325 of HCMV to induce T-cell immune responses. To evaluate the effectiveness of vaccines, we subsequently measured the expression of surface molecule markers and proinflammatory cyto-kines from antigen presenting cells in vivo and in vitro as well as the activation of T cells and antibodies. The results demonstrated that this polypeptide vaccine could activate innate immunity including up-regulating MHCI, II, CD80, CD86, and cytokine expression through the TLR4/NF-kappa B pathway. Meanwhile, vaccinations elicited potent neutralizing antibody and cellular immune responses producing TNF-alpha, INF-gamma and IL-2, indicating Th1-biased polarization. This finding underlines that CRM197-conjugated polypeptide vaccines facilitate a synergism of humoral and cellular immunity, providing enhanced protection against HCMV, which could be a potential strategy to prevent CMV-associated diseases.

Type III interferons (IFNLs) have critical roles in the host's innate immune system, also serving as the first line against pathogenic infections of mucosal surfaces. In mammals, several IFNLs have been reported; however, only limited data on the repertoire of IFNLs in avian species is available. Previous studies showed only one member in chicken (chIFNL3). Herein, we identified a novel chicken IFNL for the first time, termed chIFNL3a, which contains 354 bp, and encodes 118 amino acids. The predicted protein is 57.1% amino acid identity with chIFNL. Genetic, evolutionary, and sequence analyses indicated that the new open reading frame (ORF) groups with type III chicken IFNs represent a novel splice variant. Compared to IFNs from different species, the new ORF is clustered within the type III IFNs group. Further study showed that chIFNL3a could activate a panel of IFN-regulated genes and function mediated by the IFNL receptor, and chIFNL3a markedly inhibited the replication of Newcastle disease virus (NDV) and influenza virus in vitro. These data collectively shed light on the repertoire of IFNs in avian species and provide useful information that further elucidate the interaction of the chIFNLs and viral infection of poultry. IMPORTANCE Interferons (IFNs) are critical soluble factors in the immune system, and are composed of 3 types (I, II, and III) that utilize different receptor complexes (IFN-αR1/IFN-αR2, IFN-γR1/IFN-γR2, and IFN-λR1/IL-10R2, respectively). Herein, we identified IFNL from the genomic sequences of chicken and termed it chIFNL3a, located on chromosome 7 of chicken. Phylogenetically clustered with all known types of chicken IFNs, the finding of this IFN is considered a type III IFN. To further evaluate the biological properties of chIFNL3a, the target protein was prepared by the baculovirus expression system (BES), which could markedly inhibit the replication of NDV and influenza viruses. In this study, we uncovered a new interferon lambda splice variant of chicken, termed chIFNL3a, which could inhibit viral replication in cells. Importantly, these novel findings may extend to other viruses, offering a new direction for therapeutic interventions.