scholarly journals African Swine Fever Virus Protein p17 Is Essential for the Progression of Viral Membrane Precursors toward Icosahedral Intermediates

2010 ◽  
Vol 84 (15) ◽  
pp. 7484-7499 ◽  
Author(s):  
Cristina Suárez ◽  
Javier Gutiérrez-Berzal ◽  
Germán Andrés ◽  
María L. Salas ◽  
Javier M. Rodríguez

ABSTRACT The first morphological evidence of African swine fever virus (ASFV) assembly is the appearance of precursor viral membranes, thought to derive from the endoplasmic reticulum, within the assembly sites. We have shown previously that protein p54, a viral structural integral membrane protein, is essential for the generation of the viral precursor membranes. In this report, we study the role of protein p17, an abundant transmembrane protein localized at the viral internal envelope, in these processes. Using an inducible virus for this protein, we show that p17 is essential for virus viability and that its repression blocks the proteolytic processing of polyproteins pp220 and pp62. Electron microscopy analyses demonstrate that when the infection occurs under restrictive conditions, viral morphogenesis is blocked at an early stage, immediately posterior to the formation of the viral precursor membranes, indicating that protein p17 is required to allow their progression toward icosahedral particles. Thus, the absence of this protein leads to an accumulation of these precursors and to the delocalization of the major components of the capsid and core shell domains. The study of ultrathin serial sections from cells infected with BA71V or the inducible virus under permissive conditions revealed the presence of large helicoidal structures from which immature particles are produced, suggesting that these helicoidal structures represent a previously undetected viral intermediate.

Pathogens ◽  
2021 ◽  
Vol 10 (6) ◽  
pp. 757
Author(s):  
Sandra Barroso-Arévalo ◽  
Jose A. Barasona ◽  
Estefanía Cadenas-Fernández ◽  
José M. Sánchez-Vizcaíno

African swine fever virus (ASFv) is one of the most challenging pathogens to affect both domestic and wild pigs. The disease has now spread to Europe and Asia, causing great damage to the pig industry. Although no commercial vaccine with which to control the disease is, as yet, available, some potential vaccine candidates have shown good results in terms of protection. However, little is known about the host immune mechanisms underlying that protection, especially in wild boar, which is the main reservoir of the disease in Europe. Here, we study the role played by two cytokines (IL-10 and IFN-γ) in wild boar orally inoculated with the attenuated vaccine candidate Lv17/WB/Rie1 and challenged with a virulent ASFv genotype II isolate. A group of naïve wild boar challenged with the latter isolate was also established as a control group. Our results showed that both cytokines play a key role in protecting the host against the challenge virus. While high levels of IL-10 in serum may trigger an immune system malfunctioning in challenged animals, the provision of stable levels of this cytokine over time may help to control the disease. This, together with high and timely induction of IFN-γ by the vaccine candidate, could help protect animals from fatal outcomes. Further studies should be conducted in order to support these preliminary results and confirm the role of these two cytokines as potential markers of the evolution of ASFV infection.


Pathogens ◽  
2020 ◽  
Vol 9 (12) ◽  
pp. 1078 ◽  
Author(s):  
Albert Ros-Lucas ◽  
Florencia Correa-Fiz ◽  
Laia Bosch-Camós ◽  
Fernando Rodriguez ◽  
Julio Alonso-Padilla

African swine fever virus is the etiological agent of African swine fever, a transmissible severe hemorrhagic disease that affects pigs, causing massive economic losses. There is neither a treatment nor a vaccine available, and the only method to control its spread is by extensive culling of pigs. So far, classical vaccine development approaches have not yielded sufficiently good results in terms of concomitant safety and efficacy. Nowadays, thanks to advances in genomic and proteomic techniques, a reverse vaccinology strategy can be explored to design alternative vaccine formulations. In this study, ASFV protein sequences were analyzed using an in-house pipeline based on publicly available immunoinformatic tools to identify epitopes of interest for a prospective vaccine ensemble. These included experimentally validated sequences from the Immune Epitope Database, as well as de novo predicted sequences. Experimentally validated and predicted epitopes were prioritized following a series of criteria that included evolutionary conservation, presence in the virulent and currently circulating variant Georgia 2007/1, and lack of identity to either the pig proteome or putative proteins from pig gut microbiota. Following this strategy, 29 B-cell, 14 CD4+ T-cell and 6 CD8+ T-cell epitopes were selected, which represent a starting point to investigating the protective capacity of ASFV epitope-based vaccines.


2021 ◽  
Author(s):  
Vlad Petrovan ◽  
Anusyah Rathakrishnan ◽  
Muneeb Islam ◽  
Lynnette Goatley ◽  
Katy Moffat ◽  
...  

The limited knowledge on the role of many of the approximately 170 proteins encoded by African swine fever virus restricts progress towards vaccine development. In this study we investigated the effect of deleting combinations of different genes from a previously attenuated virus, BeninΔDP148R on: virus replication in macrophages, virus persistence and clinical signs post immunization, and induction of protection against challenge. Deletion of either EP402R or EP153R genes individually or in combination from BeninΔDP148R did not reduce virus replication in vitro. However, deletion of EP402R dramatically reduced viral persistence in vivo, whilst maintaining high levels of protection against challenge. The additional deletion of EP153R (BeninΔDP148RΔEP153RΔEP402R) further attenuated the virus and no viremia or clinical signs were observed post immunization. This was associated with decreased protection and detection of moderate levels of challenge virus in blood. Interestingly, the deletion of EP153R alone from BeninΔDP148R did not result in further virus attenuation and a slight increase in virus genome copies in blood was observed at different times post immunization when compared with BeninΔDP148R. These results show that EP402R and EP153R have a synergistic role in promoting viremia, however EP153R alone does not seem to have a major impact on virus levels in blood.


Microbiology ◽  
2000 ◽  
Vol 81 (1) ◽  
pp. 59-65 ◽  
Author(s):  
Inmaculada Galindo ◽  
Eladio Viñuela ◽  
Angel L. Carrascosa

The open reading frame B438L, located within the EcoRI B fragment of the African swine fever virus genome, is predicted to encode a protein of 438 amino acids with a molecular mass of 49·3 kDa. It presents a cell attachment RGD (Arg–Gly–Asp) motif but no other significant similarity to protein sequences in databases. Northern blot and primer extension analysis showed that B438L is transcribed only at late times during virus infection. The B438L gene product has been expressed in Escherichia coli, purified and used as an antigen for antibody production. The rabbit antiserum specific for pB438L recognized a protein of about 49 kDa in virus-infected cell extracts. This protein was synthesized late in infection by all the virus strains tested, was located in cytoplasmic virus factories and appeared as a structural component of purified virus particles.


2004 ◽  
Vol 78 (18) ◽  
pp. 9731-9739 ◽  
Author(s):  
A. Eulálio ◽  
I. Nunes-Correia ◽  
A. L. Carvalho ◽  
C. Faro ◽  
V. Citovsky ◽  
...  

ABSTRACT African swine fever virus (ASFV), a large icosahedral deoxyvirus, is the causative agent of an economically relevant hemorrhagic disease that affects domestic pigs. The major purpose of the present study was to investigate the nuclear transport activities of the ASFV p37 and p14 proteins, which result from the proteolytic processing of a common precursor. Experiments were performed by using yeast-based nucleocytoplasmic transport assays and by analysis of the subcellular localization of different green fluorescent and Myc fusion proteins in mammalian cells. The results obtained both in yeast and mammalian cells clearly demonstrated that ASFV p14 protein is imported into the nucleus but not exported to the cytoplasm. The ability of p37 protein to be exported from the nucleus to the cytoplasm of both yeast and mammalian cells was also demonstrated, and the results clearly indicate that p37 nuclear export is dependent on the interaction of the protein with the CRM-1 receptor. In addition, p37 was shown to exhibit nuclear import activity in mammalian cells. The p37 protein nuclear import and export abilities described here constitute the first report of a nucleocytoplasmic shuttling protein encoded by the ASFV genome. Overall, the overlapping results obtained for green fluorescent protein fusions and Myc-tagged proteins undoubtedly demonstrate that ASFV p37 and p14 proteins exhibit nucleocytoplasmic transport activities. These findings are significant for understanding the role these proteins play in the replication cycle of ASFV.


1994 ◽  
Vol 6 (3) ◽  
pp. 360-365 ◽  
Author(s):  
José Pérez ◽  
Francisco Rodríguez ◽  
Antonio Fernández ◽  
Juana Martín de las Mulas ◽  
José Carlos Gómez-Villamandos ◽  
...  

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