Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: 7/1/2005
Publication Date: 9/13/2005
Citation: Risatti, G.R., Holinka, L.G., Lu, Z., Kutish, G.F., Rock, D.L., Borca, M.V. 2005. Chimeric Classical Swine Fever Virus Containing the E2 Gene from a Vaccine Strain in the Genetic Background of Strain Brescia Induces Solid Early Protection in Swine. 6th Pestivirus Symposium, Thun, Switzerland.Page 89, P5-10 Interpretive Summary:
Technical Abstract: To identify genetic determinants of classical swine fever virus (CSFV) virulence, we constructed chimeras of the highly pathogenic Brescia strain and the attenuated vaccine strains CS and evaluated for viral virulence in swine. Using this approach, we recently demonstrated that chimeras 138.8 virus (v) and 337.14v (containing the E2 glycoprotein of CS in the Brescia background) were attenuated in swine despite exhibiting unaltered growth characteristics on primary porcine macrophage cell cultures. Additionally, viral chimeras 319.1v, which contained only CS E2 glycoprotein in the Brescia background, was markedly attenuated in pigs, exhibiting significantly decreased virus replication in tonsils, a transient viremia, limited generalization of infection, and decreased virus shedding. These results demonstrate the CS E2 alone is sufficient for attenuating virulent strain Brescia, indicating a significant role for the CSFV E2 glycoprotein in swine virulence. Here we show that chimeric virus 138.8v, used as an experimentally live attenuated vaccine, efficiently protect swine against the lethal challenge of pathogenic CSFV strain Brescia. Notably, 138.8v infected animals challenged at 3 and 28 days post inoculation were completely protected from clinical disease. Replication of CSFV strain Brescia in tonsils, viremia, and oronasal shedding were drastically reduced in challenged animals. These data indicate that 138.8v could be used as a template for the development of a live attenuated virus vaccine.