VEGF expression patterns in neonatal and adult thymus. (A) VEGF protein levels from “thymocyte-depleted” lysates from neonate and adult thymi. *P = .02. (B) VEGF and β-actin expression from RNA isolated from bulk thymic cells from neonates and adults. “+ control” lane contains mouse reference RNA. (C) VEGF and β-actin mRNA expression in stromal (CD45⁻MHCII⁻), hematopoietic (CD45⁺MHCII⁻), and epithelial (CD45⁻MHCII⁺) cells from neonatal thymus. (D) VEGF and actin mRNA expression from FACS-isolated DN (CD4⁻CD8⁻) thymocyte subsets in neonatal thymus. The vertical lines in panels B through D indicate repositioned gel lanes. Error bars represent standard deviation.