Reverse interference method for measurement of hog cholera virus (HCV) and anti-HCV antibody

A new procedure was developed for the assay of the hog cholera virus (HCV) and anti-HCV antibody. Initially, the suppression effect of HCV on interferon (IFN) by HCV production was confirmed. Swine kidney cell cultures preinfected with HCV produced no IFN, even following the addition of IFN inducers. However the sensitivity of the cell to IFN was not influenced by the infection with this virus. Based on these results, a new method, named reverse interference method, was established. In this method, infective titer of HCV was determined by the appearance of cell pathogenic effects (CPE) induced by vesicular stomatitis virus (VSV), which is caused by the suppression effect on the heterologous interference of GPE- strain of HCV against VSV infection in swine kidney cell cultures. This method showed nearly the same sensitivity as the END method. There was no difference in the infective titer of HCV and antibody titer against HCV as estimated by this method and the END method. The reverse interference method had advantages in rapidity and objectivity compared with the END method.