Isolation and Culture of Cell Lines

Clinically healthy turbots (20 ± 1.87 g) were purchased from a local fish farm and maintained at 20 °C in aerated seawater. The fish were acclimatized in the laboratory for 2 weeks before experimental manipulation. BALB/c mice (female, 8 weeks, 18 ± 0.55 g) were purchased from Qingdao Daren Fortune Animal Technology Co., Ltd (Qingdao, China). For tissue collection, fish were euthanized with tricaine methanesulfonate (Sigma, St. Louis, MO, USA), and mice were anesthetized with ketamine (80 mg/kg) (Ketavet, Pfizer, Berlin, Germany) as described previously [24 (link)]. The murine macrophage cell line J774A.1 and the human epithelial cell line HeLa cells were obtained from China Infrastructure of Cell Lines Resource (China). The cells were cultured in DMEM medium (Gibco, Carlsbad, CA, USA) supplemented with 10% (v/v) FBS (Gibco, Carlsbad, CA, USA) at 37°C with 5% CO₂.