Chicken infectious anemia virus (CIAV) VP1 antagonizes type I interferon (IFN-I) production by inhibiting TBK1 phosphorylation

Identification of host factors affecting Chicken Infectious Anemia Virus infection and pathogenicity through RNA-seq and LC-MS

Chicken Infectious Anemia Virus (CIAV) infection causes severe anemia, hematopoietic disorders, and immunosuppression in poultry. However, the mechanisms underlying its pathogenicity remain poorly understood. In this study, RNA sequencing (RNA-seq) was employed to investigate the transcriptional response of MSB1 cells to CIAV infection at 12, 24, and 48 hours post-infection. The results revealed differential gene expression associated with immune response, inflammatory response, apoptosis, and metabolic pathways. Several immune-related factors, including IL18, TRAF1, MYD88, IRF2, and CD28, were found to be downregulated. VP1, the capsid protein of CIAV, plays a significant role in viral pathogenicity. To explore how VP1 affects CIAV replication and pathogenicity, co-immunoprecipitation (Co-IP) was used to identify host proteins interacting with VP1. Liquid chromatography-mass spectrometry (LC-MS) analysis revealed that VP1 interacts with a range of host proteins involved in metabolic pathways, the PI3K-AKT signaling pathway, and ribosomal functions. Based on RNA-seq and LC-MS findings, ANXA6 and HSP90aa1 were identified as key interacting partners, which co-localize in the cytoplasm of infected cells. Both proteins are involved in immune responses and metabolic regulation and were found to be downregulated in CIAV-infected cells. Notably, overexpression of ANXA6 or HSP90aa1 inhibited CIAV infection during the early stages of the viral lifecycle. These findings enhance our understanding of the host factors influencing CIAV infection and provide new insights into potential therapeutic targets for managing CIAV-induced diseases.

A strain of Lactobacillus plantarum from piglet intestines enhances the anti-PoRV effect via the STING-IFN-I pathway

BACKGROUND

Rotavirus infection represents a major etiology of severe diarrheal disease in neonatal and weaned piglets, causing substantial economic burdens to the global swine industry. Lactobacillus plantarum, a ubiquitous probiotic in natural ecosystems, has demonstrated multifaceted biological functions. The stimulator of the interferon gene (STING) is involved in type I interferon (IFN-I) mediated host antiviral innate immunity, which is a pivotal adaptor in response to the microbial DNA/RNA-activated signaling pathways. Emerging evidence suggests that certain probiotic strains can activate the STING-dependent pathway to induce IFN-I responses. In the present study, we successfully isolated a strain of Lactobacillus plantarum (designated LP1)from porcine intestinal contents and investigate its potential to counteract porcine rotavirus (PoRV) infection via modulation of antiviral signaling pathway.

RESULT

LP1 exhibited superior tolerance to simulated gastrointestinal conditions (pH 3.0 and 0.3% bile salts) compared with other isolated Lactobacillus strains. In vitro adhesion assays demonstrated that LP1effectively colonized porcine intestinal epithelial cells (IPEC-J2) without inducing cytotoxicity or apoptosis. Animal experiments also confirmed the protective effect of LP1 in mice against rotavirus, by reducing body weight loss, promoting viral clearance in feces, and alleviating intestinal mucosal damage. Mechanistic investigations identified STING-IRF3 pathway activation as the pivotal antiviral mechanism. Both phosphorylation of STING and IRF3 in LP1-treated IPEC-J2 cells accompanied by upregulated transcription and secretion of IFN-β and interferon-stimulated genes (ISGs). Consistent findings were observed in intestinal tissues of LP1-protected mice with STING pathway activation correlating with reduction in viral titers. Crucially, STING inhibitor (C-170) administration could reverse LP1-mediated antiviral effects.

CONCLUSION

LP1 exerts potent anti-PoRV activity in both murine models and porcine intestinal epithelial (IPEC-J2) cells through STING-IRF3 signaling axis-mediated IFN-β production.

A σC-protein-based indirect enzyme-linked immunosorbent assay for clinical detection of antiavian reovirus antibodies

Avian reovirus (ARV) is the causative agent of avian viral arthritis and causes significant economic losses to the global poultry industry. For clinical diagnosis, detecting ARV-specific antibodies is crucial. We successfully expressed the ARV-σC protein in insect cells using the baculovirus expression vector system, achieving an expression level of approximately 200 mg/L. We developed an indirect enzyme-linked immunosorbent assay (iELISA) using the ARV-σC protein as a coating antigen to detect antibodies against it. The inter-batch and intrabatch coefficients of iELISA variation were less than 10%. Its sensitivity (1:12,800 diluted in serum) was 4 times higher than that of the indirect immunofluorescence assay (IFA; 1:3200 diluted in serum), and it showed no cross-reactivity with antibodies against other common avian viruses (such as Infectious bursal disease virus, Newcastle disease virus). The practicality of the iELISA was further evaluated using clinical samples. 300 clinical sera from chickens vaccinated with the ARV attenuated vaccine and 20 SPF sera were tested using both the iELISA and the IFA, demonstrating a 100% conformity rate. In conclusion, these results suggest that the iELISA developed in this study is a rapid, sensitive, and specific method that could serve as an effective diagnostic tool for monitoring and controlling avian viral arthritis.

Gyrovirus: current status and challenge

Gyrovirus (GyV) is small, single-stranded circular DNA viruses that has recently been assigned to the family Anelloviridae. In the last decade, many GyVs that have an apparent pan-tropism at the host level were identified by high-throughput sequencing (HTS) technology. As of now, they have achieved global distribution. Several species of GyVs have been demonstrated to be pathogenic to poultry, particularly chicken anemia virus (CAV), causing significant economic losses to the global poultry industry. Although GyVs are highly prevalent in various birds worldwide, their direct involvement in the etiology of specific diseases and the reasons for their ubiquity and host diversity are not fully understood. This review summarizes current knowledge about GyVs, with a major emphasis on their morphofunctional properties, epidemiological characteristics, genetic evolution, pathogenicity, and immunopathogenesis. Additionally, the association between GyVs and various diseases, as well as its potential impact on the poultry industry, have been discussed. Future prevention and control strategies have also been explored. These insights underscore the importance of conducting research to establish a virus culture system, optimize surveillance, and develop vaccines for GyVs.

Development of a lateral flow assay for rapid and accurate detection of chicken anemia virus

Significant challenges to poultry health are posed by chicken anemia virus (CAV), which induces immunosuppression and causes increased susceptibility to secondary infections. The effective management and containment of CAV within poultry stocks require precise and prompt diagnosis. However, a deficiency persists in the availability of low-cost, rapid, and portable CAV detection devices. In this study, an immunochromatographic lateral-flow test strip-based assay was developed for CAV detection using in-house generated monoclonal antibodies (MABs) against CAV viral protein 1 (VP1). The recombinant truncated VP1 protein (Δ60VP1), with amino acid residues 1 to 60 of the native protein deleted, was produced via a prokaryotic expression system and utilized for immunizing BALB/c mice. Subsequently, high-affinity MABs against Δ60VP1 were generated and screened using conventional hybridoma technology combined with serial dilution assays. Two MABs, MAB1, and MAB3, both binding to distinct epitopes of Δ60VP1, were selected for the development of a lateral-flow assay. Sensitivity analysis demonstrated that the Δ60VP1 antigen could be detected by our homemade lateral-flow assay at concentrations as low as 625 ng/mL, and this sensitivity was maintained for at least 6 mo. The assay exhibited high specificity, as evidenced by its lack of reactivity with surrogate recombinant proteins and the absence of cross-reactivity with other chicken viruses and viral antigens. Comparative analysis with quantitative PCR data demonstrated substantial agreement, with a Kappa coefficient of 0.66, utilizing a sample set comprising 305 clinical chicken serum samples. In conclusion, the first lateral-flow assay for CAV detection was developed in this study, utilizing 2 specific anti-VP1 MABs. It is characterized by simplicity, rapidity, sensitivity, and specificity.