Canine Distemper Virus Propagation

Mv. l. Lu cells in this study were maintained in Minimal Essential Media (MEM, Gibco, Life Technologies, Grand Island, NY, USA) supplemented with 10% fetal bovine serum (FBS) (Invitrogen, Waltham, MA, USA) and cultured at 37°C in a 5% CO₂ incubator. CDV PS strain (GenBank No.: JN896331) was isolated from dogs of CD in 2013 by our laboratory (22 (link)). Due to the low viral titer of PS strain and the presence of cytokines in the virus venom, the virus was proliferated by Mv. l. Lu cells and then collected. The virus was concentrated by PEG 6000 (Thermo Fisher Scientific, Waltham, MA, USA) and purified by super centrifugation using the sucrose gradient method (23 (link)). The purified viruses were stored at −80°C before use. The titer of the virus was determined by the median tissue culture infective dose method (24 (link)).