VEGF-A is expressed in the inflamed ears but not in the draining LNs. A DTH response was induced and maintained in the ears of WT or of VEGF-A Tg mice, and VEGF-A mRNA and protein levels in ears and draining auricular LN were determined on study days 2 and 9. (A) In situ hybridization on study day 9 revealed that VEGF-A mRNA was up-regulated in inflamed ears of both WT mice (WT-infl) and of VEGF-A Tg (TG-infl) mice compared with WT and VEGF-A Tg control mice (WT-ctr and TG-ctr, respectively). (B) Virtually no VEGF-A mRNA expression was detected in LN sections from inflamed or control VEGF-A Tg (TG-infl and TG-ctr) and WT mice (WT-infl and WT-ctr). (C,D) Quantitative RT-PCR was performed on RNA extracted from auricular LNs of WT (C) or of VEGF-A Tg (D) mice. No increase in VEGF-A mRNA expression in inflamed over control LNs could be detected, neither when analyzing RNA extracted on study day 2 (D2) nor on study day 9 (D9). VEGF-A mRNA levels in salivary glands were assayed as positive control. (E,F) A VEGF-A ELISA was performed on tissue homogenates of ears (E) and draining LNs (F) on study day 9. (E) VEGF-A protein concentration was significantly elevated in homogenates of inflamed ears, compared with controls. (F) The amount of VEGF-A protein was significantly higher in homogenates from inflamed LNs compared with control LNs. *P < .05; ***P < .001 (compared with control). Error bars are SE.