Immunological response to swine fever virus
The virus CSFV (Classical swine fever virus) causes the highly contagious disease swine fever. Effective control of this disease is problematic as infection with less virulent strains may be chronic. Infected piglets birthed into the population may then act to maintain swine fever in the farming unit. Moreover, wild animals like the boar are a very potent source of the virus. The European project IMPCSF aimed to research into marker vaccines with the specific intention of providing early protection. As part of the project's research into the immunological responses involved, German-based scientists at the Friedrich-Loeffler Institute for Animal Health identified CSFV-specific T-cell epitopes, parts of the antigen recognised by antibodies. In particular, they focussed on the Major histocompatabiltiy complex (MHC). The first step was to induce the production of lymphocytes in the pigs. In order to accomplish this, pigs were inoculated with the CSFV strain Glentarf. The scientist used a lympho-proliferation assay on peripheral blood mononuclear cells (PBMCs) for T cell monitoring. The identification of T cell epitopes involved techniques including the use of hydrogen-3 labelling of thymidine and overlapping peptides obtained from the Glentarf strain. The assays identified 26 peptides from the viral protein. Characterisation of the T cell epitopes was achieved using CFSE staining and flow cytometry. The team found that CD4+ T cells were mainly involved and antigens present on the cell surface included MHCII. To gain further insight into the activation potency of the T cell epitopes, they were synthesised to identify the amino acids that bind to the MHCII complex. To achieve this, the amino acids at different sites were substituted and cellular immune responses were then assayed. A sustainable swine fever control programme based on vaccination will increase the competitiveness of the European pork industry. Furthermore, it will protect the livelihood of pig farmers amidst the threat of mass culling in the event of an outbreak.
