The highly contagious classical swine fever (CSF) remains a major trade and health problem in the pig industry, causing large economic losses worldwide. Modified live vaccines (MLV), commonly derived from the attenuated CSF virus (CSFV) C-strain, have been routinely used to control the disease in CSF-endemic countries. However, to completely eradicate the disease, a potent, safe and non-infectious CSF vaccine should be easily accessible and available. This study aims to develop a cost-effective, non infectious CSF subunit vaccine that can elicit rapid and long lasting immunity. We report on a series of animal studies to study the efficacy of a CSF E2 subunit vaccine in oil-in-water emulsion adjuvant, KNB-E2. Swine vaccination and CSFV challenge experiments showed that a single KNB-E2 dose with 25 µg of recombinant CSFV glycoprotein E2 can reduce disease and protect from clinical symptoms. In addition, KNB-E2-mediated reduction of CSF symptoms was observed at two weeks post vaccination and the vaccinated pigs continued to exhibit reduced CSF clinical signs when challenged at two months and four months post vaccination. These results suggest that KNB-E2 effectively reduces CSF clinical signs and the potential of this vaccine to safely minimize CSF-related losses.
Madera RF, Wang L, Gong W, Burakova Y, Buist S, Nietfeld J, Henningson J, Ozuna AGC, Tu C, Shi J; Towards the Development of a One-Dose Classical Swine Fever Subunit Vaccine: Antigen Titration, Onset and Duration of Immunity; J Vet Sci. 2018 Mar 6. [Epub ahead of print] PMID: 29510474