IFNL1 and infection: Secreted IFN-λ1/λ3 and IFN-λ2 were significantly detected in supernatants of infected cells at 28 h post-infection and their levels increased further at 42 h, reaching ∼2000 pg/ml for IFN-λ1/λ3 and ∼500 pg/ml for IFN-λ2, at a MOI of 50–100 (Fig. 1B).