IFNL1 and infection: As shown in Fig. 2B, 18 h post-infection the levels of IFN-λ1/λ2 mRNAs did not increase upon Salmonella infection, as described above (Fig. 2A), and increased by ∼3-fold and ∼ 8-fold upon Shigella flexneri or C. trachomatis infection, respectively, compared to the level of these transcripts in uninfected cells.