Eosinophils recruited in response to Af antigens are activated and degranulate in response to PVM and promote antiviral activity. (A) mEPX was detected in BAL fluid from Af-sensitized and Af-challenged, PVM-infected B6 wild-type mice only; n = 4 to 8 mice per group; ***P < .0001 vs Af-sensitized and Af-challenged, but not PVM-infected, group, as well as all other conditions. (B) RNase activity was detected in BAL fluid from Af-sensitized and Af-challenged, PVM-infected wild-type B6 mice only; n = 4 to 8 mice per group; ***P < .0001 vs Af-sensitized and Af-challenged, but not PVM-infected, group, as well as all other conditions. (C) Transmission electron micrograph of an eosinophil isolated from the airways of an Af-sensitized and Af-challenged, PVM-infected wild-type B6 mouse. Indicated in the image are specific granules and vesiculotubular structures³⁴  analogous to those described in human eosinophils (at the large arrow); original magnification ×23 000. (D) Virus recovery from Af-sensitized and -challenged and control B6 wild-type or B6 eosinophil–deficient ΔdblGATA mice at 4 days after inoculation with PVM (see Figure 4A for timeline).