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Researchers from CReSA (Spain) have demonstrated that protecting pigs against African swine fever it is not science fiction. These are the conclusions of a study recently published in the journal PLoS One. African swine fever virus (ASFV) is in continuous expansion since its last entrance in Europe through Georgia in 2007.
The fact that the disease is endemic in Sardinia and overall, in many Sub-Saharan African countries, where it causes important loses, provoked the reentering of the virus in Europe trough Republic of Georgia in 2007. Since then, the virus has continued its expansion through adjacent countries, including Russia, where the situation remains uncontrolled nowadays.
The lack of available vaccines against ASFV complicates even more the control of the disease. Therefore, developing an efficient and safe vaccine against ASF is a must.
The last results obtained by the research group from CReSA clearly demonstrate the possibility of protecting pigs against a lethal ASFV challenge by using DNA vaccines encoding 3 of the viral antigens (ASFV encodes more than 150 different proteins). Moreover, the relevance of the CD8+ T-cells (a lymphocyte subset capable to recognize infected cells and specifically destroy them) in protection, has been definitively confirmed.
In this study, the researchers have demonstrate that DNA vaccines (in the form of innocuous DNA plasmid molecules) encoding three viral antigens (in this case a new plasmid construct, pCMV-UbsHAPQ, encoding the three viral determinants sHA, p54 and p30), are capable to provoke a significant delay on the death of the animals after ASFV lethal challenge and more importantly, that 33% of the immunized pigs survive and totally recovered from the infection. To achieve this protection, optimizing the presentation of the vaccine encoded antigens to the specific CD8+ T-cells by ubiquitination (a label that marks proteins for intracellular degradation), was mandatory. In fact, the protection conferred totally correlated with the presence of large number of specific CD8+ T-cells in the blood of surviving pigs with no need of antibodies-help.
This research group is currently in the process of characterizing new viral antigens (within the rest of the ASFV 150 proteins) with potential to provoke protective CD8+ T-cell responses.
Pérez‐Martín E, Nofrarías M, Gallardo C, Accensi F, Lacasta A, Mora M, Ballester M,
Galindo‐Cardiel I, López‐Soria S, Escribano JM, Reche PA, Rodríguez F. DNA Vaccination
Partially Protects against African Swine Fever Virus Lethal Challenge in the Absence of Antibodies. PLoS One. 2012;7(9):e40942. doi: 10.1371/journal.pone.0040942.
CReSA-Press release/ Spain.
http://www.cresa.cat/
