Development and characterization of a cell line from the snout of koi (Cyprinus carpio L.) for detection of koi herpesvirus

A permanent growing cell line, designated as koi snout (KS), was established from snout tissues of koi utilizing the trypsin method. The KS cell line was maintained in Leibovitz's L-15 medium supplemented with 10-20% fetal bovine serum (FBS) within incubation temperatures ranging from 22 to 27 °C. Maximum cell proliferation rates occurred at 27 °C in Leibovitz's L-15 medium containing 10% FBS. The KS cell line was subcultured more than 115 times, and karyotyping analysis indicated the modal chromosome number was 2n = 100. The results of virus isolation demonstrated that KS cells were susceptible to koi herpesvirus (KHV), which was demonstrated by the presence of obvious cytopathic effects and abundant virus particles with high virus titer of 106.98 TCID50/mL. Immunofluorescence and Western blot assays provided confirmation that KS could replicate KHV. The newly established KS cell line will provide a useful tool for KHV detection.