Langerin-DTR mice specifically expressed DTR on CD103+ DCs in the lung and DT administration efficiently depleted lung CD103+ DCs (Fig. S4), and subsequent influenza infection in DT-treated langerin-DTR mice did not cause increased C3a and C5a levels in the lungs on days 2 and 4 when compared with CD103+ DCs sufficient mice (Fig. 6D and E). Here, C5 is linked to influenza.