Immunogenicity of a live attenuated classical swine fever vaccine in pigs under field conditions

A study was conducted for assessing the immunogenicity of live classical swine fever (CSF) vaccine in pigs under field conditions. Pre immunization blood samples and post immunization (PI) blood samples at 30, 60, 90, and 120 days post immunization (DPI) were collected. Th1 response was assessed by the expression of IFN-gamma, IL2 and IL-12, and serum antibody titres and IL-10 expression were studied for Th2 response. The mean +/- SE of IFN-gamma gene response as fold change (2(Delta Delta Ct) values) at 30, 60, 90, and 120 days post immunization (DPI) were 9.61 +/- 0.65, 3.49 +/- 0.44, 2.22 +/- 0.407, and 3.12 +/- 1.35 respectively. IFN-gamma response showed significantly increased fold change during PI period. Significant peak increase in the expression level was observed at 30 DPI. IL-2 gene response showed significantly increased fold change during PI (Mean expression at 30, 60, 90, and 120 DPI was 4.41, 2.61, 3.291 and 2.09 respectively) and peak increase was observed at 30 DPI. IL-12 response also showed significant increase during PI with a peak expression at 30 DPI (Mean fold changes at 30, 60, 90, and 120 days post immunization were 4.92, 2.97, 2.72, and 3.61 respectively). Maximum IL-10 expression was observed at 60 DPI (Mean fold change at 30, 60, 90, and 120 days post immunization were 3.364 +/- 0.723, 11.56 +/- 1.64, 4.73 +/- 1.01, and 2.599 +/- 1.05 respectively). Pre-and post-immunization antibody responses were monitored by enzyme linked immunosorbent assay. Antibody titres increased consistently from 30 days after primary immunization until 120 days. Montanide (gel 01) coupled PK-15 adapted live, CSV vaccine induced a good Th1 response followed by Th2 response.