Development of suitable tools to produce a DISC vaccine to control African Swine Fever

African Swine Fever is a highly contagious, lethal, and economically devasting infectious disease that affects bush pigs, warthogs, domestic pigs, and wild boars. ASF is present in Africa, eastern and western Europe, Asia, and Sardinia, where it is endemic since 1978. The etiological agent of ASF is the African Swine Fever Virus (ASFV), a large, enveloped virus assembled by an icosahedral structure containing a double-strand DNA genome. The lack of a vaccine limits the options to control the disease. For this reason, it is important the development of a vaccine capable of infecting and inducing a long last immunity as well as avoiding the arise of side effects and the risk of possible recombination with the wild type virus to eradicate the disease. Therefore, the main goal of the present project is the development of a DISC vaccine specific for ASFV Sardinian isolates. Vaccines’ production requires the development of suitable continuous porcine cell lines genetically stable to support viral replication. The natural target cells for ASFV are cells derived from monocytes, in particular macrophages. At present, there are not monocyte/macrophage continuous cell lines permissive to virus replication. In the natural host, ASFV replicates in endothelial cells as well. This work showed the development of an immortalized Porcine Aortic Endothelial Cell (iPAEC) line using E6-E7 oncogenes derived from OaPV3 ovine papillomavirus. This allowed us to obtain a suitable continuous cell line derived from porcine that may be used to develop a DISC vaccine. Analysis on iPAEC cells showed that they are capable to support viral replication revealing a highly susceptibility to ASFV infection. In addition, the production of a DISC vaccine requires the deletion of selected ASFV genes. This project showed the design of synthetical target late genes and their expression in Cos-1 cell lines. The presented work allowed us to set up a strategy to develop helper cell lines expressing mutagenized genes and capable to support replication of defective viruses. The methodology here described represents a new suitable tool for vaccines development.

ASF is a highly contagious, lethal, and economically devasting infectious disease that affects bush pigs, warthogs, domestic pigs, and wild boars. It is present in Africa, eastern and western Europe, Asia, and Sardinia where it is endemic since 1978. The etiological agent is the ASFV, a large, enveloped icosahedral virus with a dsDNA genome. The lack of a vaccine limits the options to control the disease. For this reason, it is important the development of a vaccine capable of infecting and inducing a long last immunity, avoiding the arise of side effects and the risk of possible recombination with the wild type virus to eradicate the disease. The main goal of the project is the development of a DISC vaccine specific for ASFV Sardinian isolates. Vaccines production requires the development of suitable continuous porcine cell lines genetically stable to support viral replication. The natural target cells for ASFV are cells derived from monocytes, in particular macrophages. At present, there are not monocyte/macrophage continuous cell lines permissive to virus replication. In the natural host, ASFV replicates in endothelial cells as well. This work showed the development of an immortalized Porcine Aortic Endothelial Cell (iPAEC) line using E6-E7 oncogenes derived from OaPV3 ovine papillomavirus. This allowed us to obtain a suitable continuous cell line that may be used to develop a DISC vaccine. Analysis on iPAEC cells showed that they are capable to support viral replication revealing a highly susceptibility to ASFV infection. In addition, the production of a DISC vaccine requires the deletion of selected ASFV genes. This project showed the design of synthetical target late genes and their expression in Cos-1 cells. The presented work allowed us to set up a strategy to develop helper cell lines expressing mutagenized genes and capable to support replication of defective viruses. The methodology here described represents a new suitable tool for vaccines development.