IgM-Capture ELISA as a serodiagnostic test for detection of primary infection of PRRSV in pigs

摘要

An IgM-capture ELISA was developed for the detection of primary infection of porcine reproductive and respiratory syndrome virus (PRRSV) in pigs. The test was based on the use of biotinylated capture anti-swine IgM antibodies bound to a streptavidin-coated ELISA plate. The captured IgM antibodies were detected by application of tissue culture-derived PRRSV antigens and a monoclonal antibody specific for the nucleocapsid protein. The IgM-capture ELISA was compared to the indirect (IDEXX HerdCheck) anda blocking ELISA by testing serum samples from groups of pigs experimentally infected with PRRSV ISU-P strain. The IgM-capture ELISA was able to detect anti-PRRSV nucleocapsid IgM antibodies from swine serum samples collected at 7 days post infection. The blocking ELISA also detected anti-nucleocapsid antibodies at 7 days post infection, whereas the indirect ELISA detected antibodies at 14 days post infection. When the detectable IgM antibodies diminished after 40 to 60 days post infection by the IgM-capture ELISA, the IgG anti-nucleocapsid antibodies remained high and last over 120 days post infection. These results demonstrated that the IgM-capture ELISA is a useful test for serodi-agnosis of primary infection of PRRSV in pigs.