2.7 Production of specific SVV antibody
All mink were fed in the same manner. Clinical symptoms were monitored daily for 28 days. At 0, 3, 7, 14, 21, or 28 dpc, mink serum was collected to examine the quality of specific antibodies by ELISA. We expressed the VP1 protein in a prokaryotic system. The secondary horseradish peroxidase-conjugated (HRP) rabbit anti-mink IgG antibody (SolarBio, Beijing, China) was added, and then incubated for 1 h at RT, and then washed three times; o-Phenylenediamine dihydrochloride was used as the chromogen. The absorbance was measured at 490 nm by using an ELx800 microplate reader (BioTek Instruments, Winooski, VT, USA). The results of each group of plates were standardized using a panel of reference IgG negatives and positives. Positive/negative (P/N) ratios > 2 were considered positive.