Decreased and abbreviated ear swelling and diminished angiogenesis in DTH reactions elicited in PlGF-2–deficient mice.

DTH reactions were induced in the ear skin of PlGF-2–deficient and wild-type mice using oxazolone. (A). Ear swelling is expressed as the increase (Δ) over the original ear thickness in micrometers. PlGF-2–deficient mice (●) showed a significantly decreased ear swelling (P < .01 at 48 hours; P < .05 at 24 hours, 3 and 6 days after challenge) as compared with wild-type mice (▪). Moreover, the duration of ear swelling in PlGF-2–deficient mice was abbreviated. Unchallenged mice: ○, PlGF-2–deficient mice; ■, wild-type mice. Data are expressed as means ± SEMs. **P < .01. Diminished edema formation and inflammatory infiltration in the skin of PlGF-2–deficient mice (C) at 24 hours after antigen challenge as compared with wild-type mice (B). CD31 stains demonstrated absence of large angiogenic vessels 24 hours after challenge in PlGF-2–deficient mice (E) as compared with wild-type mice (D). (B-C) Hematoxylin and eosin stains. (D-E) CD31 stains. Scale bars = 50 μm.