Project description:African swine fever (ASF) is the most dangerous disease of pigs and causes enormous economic losses in the global pig industry. However, the mechanism of ASF virus (ASFV) infection is unclear. Hence, we wanted to understand the host response mechanism upon ASFV infection. We analyzed the differentially expressed proteins (DEPs) between ASFV-infected and un-infected serum samples using quantitative proteomics. Setting the p-value < 0.05 and |log2 (fold change)| > 1.5, we identified 173 DEPs, including 57 upregulated and 116 downregulated proteins, which belonged to various biological processes and pathways according to the Gene Ontology and Kyoto Encyclopedia of Genes and Genomes pathway enrichment analyses. The enriched pathways include the immune system, metabolism, and inflammation.
Project description:In field studies and carefully controlled artificial infections, there is host variation in response to ASF infections. To better understand the mechanisms underlying this diversity and distinguish between resilient and susceptible pigs to African Swine Fever (ASF), the differentially expressed genes (DEGs) were studied between the recovered versus non-recovered pigs before and after an infection challenge and also among non-recovered animals over time. In total, 17 Babraham pigs were sampled. Twelve animals were randomly immunized with low virulent ASFV isolate, and the others received the sham vaccine. All animals were then challenged with the virulent ASFV isolate 18 days after the immunization. Except for five animals, all showed clinical signs and dead between 4 and 6 days later. RNA sequencing was done for whole blood samples collected pre-infection, one day, and one week post-infection.
Project description:African swine fever (ASF) is a deadly disease of swine currently causing a worldwide pandemic leading to severe economic consequences for the porcine industry. The control of disease spread is hampered by the limitation of available effective vaccines. Live attenuated vaccines (LAVs) are currently the most advanced vaccine prototypes, providing strong protection against ASF. However, the significant advances achieved using LAVs must be complemented with further studies to analyse vaccine-induced immunity. Here we characterized the onset of cross-protective immunity triggered by the LAV candidate BA71ΔCD2. Intranasally vaccinated pigs were challenged with the virulent Georgia 2007/1 strain at days 3, 7 and 12 postvaccination. Only the animals vaccinated 12 days before challenge effectively controlled infection progression, showing low virus loads, minor clinical signs and lack of the unbalanced inflammatory response characteristic of severe disease. Contrarily, animals vaccinated 3 or 7 days before challenge just showed a minor delay of disease progression. Virus-specific antibody responses and whole blood transcriptome signatures demonstrated that control of infection is associated with the presence of virus-specific antibodies and a cytotoxic response before challenge. These results contribute to our understanding of protective immunity induced by LAV-based vaccines, encouraging their use in emergency responses in ASF affected areas.
Project description:African swine fever virus (ASFV) is a large, icosahedral, double-stranded DNA virus in the Asfarviridae family and the causative agent of African swine fever (ASF). ASFV causes a hemorrhagic fever with high mortality rates in domestic and wild pigs. ASFV contains an open reading frame named EP152R, previous research has shown that EP152R is an essential gene for virusrescue in swine macrophages. However, the detailed functions of ASFV EP152R remain elusive. Herein, we demonstrate that EP152R, a membrane protein located in the endoplasmic reticulum (ER), induces ER stress and swelling, triggering the PERK/eIF2α pathway and broadly inhibiting host protein synthesis in vitro. Additionally, EP152R strongly promotes immune evasion, reduces cell proliferation, and alters cellular metabolism. These results suggest that ASFV EP152R plays a critical role in the intracellular environment, facilitating viral replication. Furthermore, virus-level experiments have shown that the knockdown of EP152R or PERK inhibitors efficiently affects viral replication by decreasing viral gene expression. In summary, these findings reveal a series of novel functions of ASFV EP152R and have important implications for understanding host-pathogen interactions.
Project description:The ongoing African swine fever (ASF) pandemic continues to have a major impact on global pork production and trade. Since ASF cannot be distinguished from other swine hemorrhagic fevers clinically, ASF-specific laboratory diagnosis is critical. Thus ASF virus (ASFV)-specific monoclonal antibodies (mAbs) are critical for the development of laboratory diagnostics. In this study, we report one ASFV-specific mAb, F88ASF-55, that was generated and characterized. A proteomic approach was performed to determine the sequence identities of the protein band (14 kDa) recognized by F88ASF-55. The stained protein band was excised, digested, and analyzed by LC-MS/MS. A total of 10 exclusive unique peptides and 15 exclusive unique spectra were identified (data not shown). The amino acid coverage (88/137) of the structural protein encoded by A137R was 64.2%. The results confirmed that the mAb-binding epitope is located on the protein encoded by A137R (formerly known as p11.5). Epitope mapping results revealed a highly conserved linear epitope recognized by this mAb, corresponding to amino acids 111-125 of pA137R.
Project description:African swine fever virus (ASFV) is a highly infectious and lethal swine pathogen that causes severe socio-economic consequences in affected countries. Unfortunately, effective vaccine for combating ASF is unavailable so far, and the prevention and control strategies for ASFV are still very limited. Toosendanin (TSN), a triterpenoid saponin extracted from the medicinal herb Melia toosendan Sieb. Et Zucc, has been demonstrated to possess analgesic, anti-inflammatory, anti-botulism and anti-microbial activities, and was used clinically as an anthelmintic, while the antiviral effect of TSN on ASFV has not been reported. In this study, we revealed that TSN exhibited a potent inhibitory effect on ASFV GD955-38 strain in porcine alveolar macrophages (PAMs) (EC50=0.085 μM, SI = 365) in a dose-dependent manner. TSN showed robust antiviral activity in different doses of ASFV infection and reduced the transcription and translation levels of ASFV p30 protein, viral genomic DNA quantity as well as viral titer at 24 and 48 hours post-infection. In addition, TSN did not affect virion attachment and release but intervened in its internalization in PAMs. Further investigations disclosed that TSN played its antiviral role by upregulating the host IFN-stimulated gene (ISG) IRF1 rather than by directly inactivating the virus particles. Overall, our results suggest that TSN is an effective antiviral agent against ASFV replication in vitro and may have the potential for clinical use.