The Use of ELISA in Classical Swine Fever Virus Antibody Monitoring in Taiwan

Abstract

The aim of this study was to establish a quantitative classical swine fever virus (CSFV) antibody monitoring system in Taiwan. First, we used a set of serum samples from vaccinated pigs to correlate antibody titers against CSFV between a virus neutralization (VN) test and a blocking enzyme-linked immunosorbent assay (ELlSA). A good correlation (r = 0.892) was found between the VN and the ELlSA results. To establish a reference serological profile for groups with good vaccination efficacy, 300 serum samples from 14 pig farms that displayed good immune responses with lapinized Chinese C (LPC) vaccination were used in this assay. The mean ELlSA antibody inhibition value (%) was 104.6% in these pigs. To evaluate the interference of maternal antibody, three-and six-week-old pigs with different levels of maternal antibody were vaccinated with LPC vaccine, and the antibody response was assayed six weeks later. Seroconversion of the piglets displayed a quadratic regression correlation against maternal antibody levels. Serum samples of LPC-vaccinated pigs and of pigs infected with the CSFV could be differentiated by the blocking ELlSA kit if the serum samples were diluted 20-fold. In conclusion, the commercially available CSFV ELlSA kit results have a high correlation with the VN test results and can be used in the quantitative assessment of levels of CSFV antibody in Taiwan.