Cell Culture
Channel catfish ovary fibroblasts (CCO, ATCC CRL-2772) were used for allin vitro assays. CCO cells were grown in L-15 medium (Sigma) supplemented with 10% fetal bovine serum (FBS, Atlanta Biologicals). For general maintenance and growth, CCO cells were cultured in T75 plug sealed flasks (Corning, Fisher Scientific) in a humidified incubator at 28°C. Typical passage ratio at 1:3 was approximately once a week and media changed every 3 days.