Comparison of liquid phase blocking ELISA and neutralization peroxidase linked assay for antigenic characterization of Classical swine fever virus isolates

Comparison of liquid phase blocking ELISA (LPBE) and neutralization peroxidase linked assay (NPLA) was made for antigenic characterization of 12 Classical swine fever (CSF) virus isolates from different places of Assam. The tests were performed using polyclonal serum raised against cell culture adapted lapinized CSF vaccine virus strain. In LPBE, 50% inhibition log titre of CSF virus isolates ranged from 1.204 to 2.107 and the highest titre was found with the homologous vaccine strain. The neutralization log titre in NPLA ranged from 1.505 to 1.806 and the highest neutralization log titre was also found with the homologous vaccine virus. Comparison of the 50% inhibition log titres in LPBE and neutralization log titre in NPLA revealed no significant difference. The correlation between LPBE and NPLA with the mean log titres obtained by both the tests showed significant (P<0.01) positive correlation (r=0.682) between the two tests. The study showed that LPBE, which is more rapid and reproducible can be used for antigenic characterization of CSF virus isolates.