Fig. 1.

Experimental design. Hypoxia inducible factor-1α (HIF-1α)-deficient mice were generated through 3 different postnatal doxycycline (DOX) treatment schemes: postnatal day (PN)4, PN32, or PN4–14. For PN4, DOX was delivered from PN4 to PN28. For PN32, DOX was delivered from PN32 to PN42. For PN4–14, DOX was delivered from PN4 to PN14. Following at least 10 days on normal food and water, HIF-1α-sufficient and HIF-1α-deficient female mice were sensitized (S1) intraperitoneally with saline or ovalbumin (OVA) plus alum (250 μl) and 10 days later sensitized again (S2) with saline or OVA (no alum, 250 μl). Seven days later, the mice were challenged (C1–3) with saline or OVA (1% solution) via inhalation 30 min per day for 3 days. Animals were euthanized 48 h after their final challenge.