scholarly journals Deletion of a CD2-Like Gene, 8-DR, from African Swine Fever Virus Affects Viral Infection in Domestic Swine

1998 ◽  
Vol 72 (4) ◽  
pp. 2881-2889 ◽  
Author(s):  
M. V. Borca ◽  
C. Carrillo ◽  
L. Zsak ◽  
W. W. Laegreid ◽  
G. F. Kutish ◽  
...  
Keyword(s):  
Viral Infection ◽  
Mononuclear Cells ◽  
African Swine Fever Virus ◽  
Disease Onset ◽  
African Swine Fever ◽  
Fever Virus ◽  
Parental Virus ◽  
Viral Virulence

ABSTRACT An African swine fever virus (ASFV) gene with similarity to the T-lymphocyte surface antigen CD2 has been found in the pathogenic African isolate Malawi Lil-20/1 (open reading frame [ORF] 8-DR) and a cell culture-adapted European virus, BA71V (ORF EP402R) and has been shown to be responsible for the hemadsorption phenomenon observed for ASFV-infected cells. The structural and functional similarities of the ASFV gene product to CD2, a cellular protein involved in cell-cell adhesion and T-cell-mediated immune responses, suggested a possible role for this gene in tissue tropism and/or immune evasion in the swine host. In this study, we constructed an ASFV 8-DR gene deletion mutant (Δ8-DR) and its revertant (8-DR.R) from the Malawi Lil-20/1 isolate to examine gene function in vivo. In vitro, Δ8-DR, 8-DR.R, and the parental virus exhibited indistinguishable growth characteristics on primary porcine macrophage cell cultures. In vivo,8-DR had no obvious effect on viral virulence in domestic pigs; disease onset, disease course, and mortality were similar for the mutant Δ8-DR, its revertant 8-DR.R, and the parental virus. Altered viral infection was, however, observed for pigs infected with Δ8-DR. A delay in spread to and/or replication of Δ8-DR in the draining lymph node, a delay in generalization of infection, and a 100- to 1,000-fold reduction in virus titers in lymphoid tissue and bone marrow were observed. Onset of viremia for Δ8-DR-infected animals was significantly delayed (by 2 to 5 days), and mean viremia titers were reduced approximately 10,000-fold at 5 days postinfection and 30- to 100-fold at later times; moreover, unlike in 8-DR.R-infected animals, the viremia was no longer predominantly erythrocyte associated but rather was equally distributed among erythrocyte, leukocyte, and plasma fractions. Mitogen-dependent lymphocyte proliferation of swine peripheral blood mononuclear cells in vitro was reduced by 90 to 95% following infection with 8-DR.R but remained unaltered following infection with Δ8-DR, suggesting that 8-DR has immunosuppressive activity in vitro. Together, these results suggest an immunosuppressive role for 8-DR in the swine host which facilitates early events in viral infection. This may be of most significance for ASFV infection of its highly adapted natural host, the warthog.

scholarly journals African Swine Fever Virus Georgia Isolate Harboring Deletions of MGF360 and MGF505 Genes Is Attenuated in Swine and Confers Protection against Challenge with Virulent Parental Virus

2015 ◽  
Vol 89 (11) ◽  
pp. 6048-6056 ◽  
Author(s):  
Vivian O'Donnell ◽  
Lauren G. Holinka ◽  
Douglas P. Gladue ◽  
Brenton Sanford ◽  
Peter W. Krug ◽  
...  
Keyword(s):  
Multigene Family ◽  
Recombinant Virus ◽  
African Swine Fever Virus ◽  
Genetically Modified ◽  
African Swine Fever ◽  
Fever Virus ◽  
Parental Virus ◽  
First Report ◽  
Highly Virulent

ABSTRACTAfrican swine fever virus (ASFV) is the etiological agent of a contagious and often lethal disease of domestic pigs that has significant economic consequences for the swine industry. The control of African swine fever (ASF) has been hampered by the unavailability of vaccines. Experimental vaccines have been developed using genetically modified live attenuated ASFVs where viral genes involved in virus virulence were removed from the genome. Multigene family 360 (MGF360) and MGF505 represent a group of genes sharing partial sequence and structural identities that have been connected with ASFV host range specificity, blocking of the host innate response, and virus virulence. Here we report the construction of a recombinant virus (ASFV-G-ΔMGF) derived from the highly virulent ASFV Georgia 2007 isolate (ASFV-G) by specifically deleting six genes belonging to MGF360 or MGF505: MGF505-1R, MGF360-12L, MGF360-13L, MGF360-14L, MGF505-2R, and MGF505-3R. ASFV-G-ΔMGF replicates as efficiently in primary swine macrophage cell cultures as the parental virus.In vivo, ASFV-G-ΔMGF is completely attenuated in swine, since pigs inoculated intramuscularly (i.m.) with either 102or 10450% hemadsorbing doses (HAD50) remained healthy, without signs of the disease. Importantly, when these animals were subsequently exposed to highly virulent parental ASFV-G, no signs of the disease were observed, although a proportion of these animals harbored the challenge virus. This is the first report demonstrating the role of MGF genes acting as independent determinants of ASFV virulence. Additionally, ASFV-G-ΔMGF is the first experimental vaccine reported to induce protection in pigs challenged with highly virulent and epidemiologically relevant ASFV-G.IMPORTANCEThe main problem for controlling ASF is the lack of vaccines. Studies focusing on understanding ASFV virulence led to the production of genetically modified recombinant viruses that, while attenuated, are able to confer protection in pigs challenged with homologous viruses. Here we have produced an attenuated recombinant ASFV derived from highly virulent ASFV strain Georgia (ASFV-G) lacking only six of the multigene family 360 (MGF360) and MGF505 genes (ASFV-G-ΔMGF). It is demonstrated, by first time, that deleting specific MGF genes alone can completely attenuate a highly virulent field ASFV isolate. Recombinant virus ASFV-G-ΔMGF effectively confers protection in pigs against challenge with ASFV-G when delivered once via the intramuscular (i.m.) route. The protection against ASFV-G is highly effective by 28 days postvaccination. This is the first report of an experimental vaccine that induces solid protection against virulent ASFV-G.

scholarly journals African Swine Fever Virus CD2v Protein Induces β-Interferon Expression and Apoptosis in Swine Peripheral Blood Mononuclear Cells

Viruses ◽  
2021 ◽  
Vol 13 (8) ◽  
pp. 1480
Author(s):  
Sabal Chaulagain ◽  
Gustavo A. Delhon ◽  
Sushil Khatiwada ◽  
Daniel L. Rock
Keyword(s):  
Mononuclear Cells ◽  
African Swine Fever Virus ◽  
African Swine Fever ◽  
Lymphoid Tissues ◽  
Hemorrhagic Disease ◽  
Peripheral Blood Mononuclear ◽  
Viral Virulence ◽  
Induced Apoptosis ◽  
In Cells

African swine fever (ASF) is a hemorrhagic disease of swine characterized by massive lymphocyte depletion in lymphoid tissues due to the apoptosis of B and T cells, a process likely triggered by factors released or secreted by infected macrophages. ASFV CD2v (EP402R) has been implicated in viral virulence and immunomodulation in vitro; however, its actual function(s) remains unknown. We found that CD2v expression in swine PK15 cells induces NF-κB-dependent IFN-β and ISGs transcription and an antiviral state. Similar results were observed for CD2v protein treated swine PBMCs and macrophages, the major ASFV target cell. Notably, treatment of swine PBMCs and macrophages with CD2v protein induced apoptosis. Immunoprecipitation and colocalization studies revealed that CD2v interacts with CD58, the natural host CD2 ligand. Additionally, CD58 knockdown in cells or treatment of cells with an NF-κB inhibitor significantly reduced CD2v-mediated NF-κB activation and IFN-β induction. Further, antibodies directed against CD2v inhibited CD2v-induced NF-κB activation and IFN-β transcription in cells. Overall, results indicate that ASFV CD2v activates NF-κB, which induces IFN signaling and apoptosis in swine lymphocytes/macrophages. We propose that CD2v released from infected macrophages may be a significant factor in lymphocyte apoptosis observed in lymphoid tissue during ASFV infection in pigs.

scholarly journals Development and In Vivo Evaluation of a MGF110-1L Deletion Mutant in African Swine Fever Strain Georgia

Viruses ◽  
2021 ◽  
Vol 13 (2) ◽  
pp. 286
Author(s):  
Elizabeth Ramirez-Medina ◽  
Elizabeth Vuono ◽  
Sarah Pruitt ◽  
Ayushi Rai ◽  
Ediane Silva ◽  
...  
Keyword(s):  
Deletion Mutant ◽  
African Swine Fever Virus ◽  
Field Isolate ◽  
African Swine Fever ◽  
Economic Losses ◽  
Swine Industry ◽  
In Vivo Evaluation ◽  
Viral Virulence

African swine fever (ASF) is currently causing an epizootic, affecting pigs throughout Eurasia, and causing significant economic losses in the swine industry. ASF is caused by African swine fever virus (ASFV) that consists of a large dsDNA genome that encodes for more than 160 genes; few of these genes have been studied in detail. ASFV contains four multi-gene family (MGF) groups of genes that have been implicated in regulating the immune response and host specificity; however, the individual roles of most of these genes have not been well studied. Here, we describe the evaluation of the previously uncharacterized ASFV MGF110-1L open reading frame (ORF) using a deletion mutant of the ASFV currently circulating throughout Eurasia. The recombinant ASFV lacking the MGF110-1L gene (ASFV-G-ΔMGF110-1L) demonstrated in vitro that the MGF110-1L gene is non-essential, since ASFV-G-ΔMGF110-1L had similar replication kinetics in primary swine macrophage cell cultures when compared to parental highly virulent field isolate Georgia2007 (ASFV-G). Experimental infection of domestic pigs with ASFV-G-ΔMGF110-1L produced a clinical disease similar to that caused by the parental ASFV-G, confirming that deletion of the MGF110-1L gene from the ASFV genome does not affect viral virulence.

scholarly journals Clinical Indicators of Moribundity in Swine Experimentally Inoculated with African Swine Fever Virus

2020 ◽  
Author(s):  
Benjamin J Hershey ◽  
Jenna L Hagart ◽  
Karyn A Havas
Keyword(s):  
Vaccine Development ◽  
African Swine Fever Virus ◽  
Significant Risk ◽  
African Swine Fever ◽  
Fever Virus ◽  
Complex Nature ◽  
Clinical Indicators ◽  
Record Data

African swine fever virus (ASFV), the causative agent of African Swine Fever (ASF), is an infectious disease of swine that is associated with high rates of morbidity and mortality in naive populations. ASFV is challenging to work with in vitro and the in vivo immune response remains an active area of study. Vaccine development, pathogenesis, and diagnostic assay development studies often require use of live swine housed in high-containment laboratories. Studies of this type are intended to obtain key data yet must minimize the pain and distress experienced by the animals. To implement humane endpoints, pigs are ideally euthanatized by barbiturate overdose prior to death from ASFV infection, as the final stages of ASF can be clinically severe. However, due to the complex nature of ASFV pathogenesis, predicting when an infected animal will become moribund and require euthanasia is difficult. The current study was intended to aid in predicting the onset of moribundity in swine. Toward this end, we performed statistical analyses of historical health record data from 103 swine experimentally infected with ASFV. Regression analysis suggested that rectal temperature has potential utility as a marker for predicting moribundity, whereas viral strain and duration of survival after inoculation were significant risk factors for death due to disease rather than euthanasia.

Phosphorylation of African swine fever virus proteins in vitro and in vivo

Biochimie ◽  
1988 ◽  
Vol 70 (5) ◽  
pp. 627-635 ◽  
Author(s):  
María L. Salas ◽  
José Salas ◽  
Eladio Viñuela
Keyword(s):  
African Swine Fever Virus ◽  
African Swine Fever ◽  
Fever Virus ◽  
Virus Proteins

scholarly journals African swine fever virus: a B cell-mitogenic virus in vivo and in vitro.

1999 ◽  
Vol 80 (6) ◽  
pp. 1453-1461 ◽  
Author(s):  
H Takamatsu ◽  
M S Denyer ◽  
C Oura ◽  
A Childerstone ◽  
J K Andersen ◽  
...  
Keyword(s):  
B Cell ◽  
African Swine Fever Virus ◽  
African Swine Fever ◽  
Fever Virus

scholarly journals Evaluation in Swine of a Recombinant Georgia 2010 African Swine Fever Virus Lacking the I8L Gene

Viruses ◽  
2020 ◽  
Vol 13 (1) ◽  
pp. 39
Author(s):  
Elizabeth Vuono ◽  
Elizabeth Ramirez-Medina ◽  
Sarah Pruitt ◽  
Ayushi Rai ◽  
Ediane Silva ◽  
...  
Keyword(s):  
Virus Replication ◽  
African Swine Fever Virus ◽  
Disease Outbreaks ◽  
African Swine Fever ◽  
Fever Virus ◽  
Transcriptional Analysis ◽  
Economic Losses ◽  
Conserved Gene

African swine fever virus (ASFV) is the causative agent of African swine fever, a disease currently causing significant economic losses in Europe and Asia. Specifically, the highly virulent ASFV strain Georgia 2010 (ASFV-G) is producing disease outbreaks in this large geographical region. The ASFV genome encodes for over 150 genes, most of which are still not experimentally characterized. I8L is a highly conserved gene that has not been studied beyond its initial description as a virus ORF. Transcriptional analysis of swine macrophages infected with ASFV-G demonstrated that the I8L gene is transcribed early during the virus replication cycle. To assess the importance of I8L during ASFV-G replication in vitro and in vivo, as well as its role in virus virulence in domestic swine, we developed a recombinant virus lacking the I8L gene (ASFV-G-ΔI8L). Replication of ASFV-G-ΔI8L was similar to parental ASFV-G replication in primary swine macrophage cultures, suggesting that the I8L gene is not essential for ASFV-G replication in vitro. Similarly, replication of ASFV-G-ΔI8L in swine intramuscularly inoculated with 102 HAD50 displayed replication kinetics similar to ASFV-G. In addition, animals inoculated with ASFV-G-ΔI8L presented with a clinical disease indistinguishable from that induced by the same dose of the virulent parental ASFV-G isolate. We conclude that deletion of the I8L gene from ASFV-G does not affect virus replication in vitro or in vivo, nor changes the disease outcome in swine.

GS-441524 inhibits African swine fever virus infection in vitro

2021 ◽  
pp. 105081
Author(s):  
Zhao Huang ◽  
Lang Gong ◽  
Zezhong Zheng ◽  
Qi Gao ◽  
Xiongnan Chen ◽  
...  
Keyword(s):  
Virus Infection ◽  
African Swine Fever Virus ◽  
African Swine Fever ◽  
Fever Virus

scholarly journals Identification of Promiscuous African Swine Fever Virus T-Cell Determinants Using a Multiple Technical Approach

Vaccines ◽  
2021 ◽  
Vol 9 (1) ◽  
pp. 29
Author(s):  
Laia Bosch-Camós ◽  
Elisabet López ◽  
María Jesús Navas ◽  
Sonia Pina-Pedrero ◽  
Francesc Accensi ◽  
...  
Keyword(s):  
T Cell ◽  
Mononuclear Cells ◽  
African Swine Fever Virus ◽  
African Swine Fever ◽  
Cd8 T Cell ◽  
Protective Role ◽  
Full Length ◽  
T Cell Epitopes ◽  
Peripheral Blood Mononuclear

The development of subunit vaccines against African swine fever (ASF) is mainly hindered by the lack of knowledge regarding the specific ASF virus (ASFV) antigens involved in protection. As a good example, the identity of ASFV-specific CD8+ T-cell determinants remains largely unknown, despite their protective role being established a long time ago. Aiming to identify them, we implemented the IFNγ ELISpot as readout assay, using as effector cells peripheral blood mononuclear cells (PBMCs) from pigs surviving experimental challenge with Georgia2007/1. As stimuli for the ELISpot, ASFV-specific peptides or full-length proteins identified by three complementary strategies were used. In silico prediction of specific CD8+ T-cell epitopes allowed identifying a 19-mer peptide from MGF100-1L, as frequently recognized by surviving pigs. Complementarily, the repertoire of SLA I-bound peptides identified in ASFV-infected porcine alveolar macrophages (PAMs), allowed the characterization of five additional SLA I-restricted ASFV-specific epitopes. Finally, in vitro stimulation studies using fibroblasts transfected with plasmids encoding full-length ASFV proteins, led to the identification of MGF505-7R, A238L and MGF100-1L as promiscuously recognized antigens. Interestingly, each one of these proteins contain individual peptides recognized by surviving pigs. Identification of the same ASFV determinants by means of such different approaches reinforce the results presented here.

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