CD63 and infection: FCoV-infected CRFK-derived EVs presented significantly elevated expression of Alix (∗∗p ≤ 0.01), TSG101 (∗∗∗p ≤ 0.001), and CD63 (∗∗p ≤ 0.01) at 48 h infection and significantly increased expression of TSG101 (∗p ≤ 0.05) at 72 h infection relative to the control EVs, respectively, (Figures 4A–C).