HAdV3-infected A549-derived EVs showed significantly increased expressions of CD9, CD63, and TSG101 relative to EVs derived from untreated cells after 48 h and 72 h infection (p ≤ 0.0001, p ≤ 0.001, and p ≤ 0.001) (Figures 5(a)–5(c)). Here, CD9 is linked to infection.