FIG. 4.

Mice lacking functional receptors for both IFN-α/β and IFN-λ exhibit high susceptibility toward HMPV. (A) Body weight changes of IFNAR1^0/0 (n = 4) and IFNAR1^0/0IL28Rα^0/0 (n = 5) mice intranasally infected with 10⁵ PFU of HMPV. Crosses indicate that animals had to be killed due to severe symptoms. (B) HMPV-RNA load in lungs at day 4 following intranasal infection with 10⁵ PFU of HMPV was determined by qRT-PCR. Combined data for two independent experiments are shown. Each dot represents the data for one animal. ***, P < 0.001.