Specific deletion of gp130 in hematopoietic and endothelial cells of gp130^flox/flox/TCre mice. (A) Immunoblots of tissue lysates probed with antibodies to gp130 or to the control protein Stat3. (B) Immunoblots of sorted CD45⁺ splenic T cells expressing CD4 or CD8 and of cultured lung endothelial cells (ECs) probed with antibodies to gp130 or Stat3. Cells were pooled from 3 mice from each genotype. (C) Confocal immunofluorescence microscopy of lung sections stained with antibodies to the endothelial-cell marker PECAM-1 (green) and to gp130 (red). Yellow staining indicates colocalization of PECAM-1 and gp130 in the endothelial cells of gp130^+/+/TCre mice. Only green staining for PECAM-1 is present in the endothelial cells of gp130^flox/flox/TCre mice. Both sections exhibit red staining for gp130 in nonendothelial cells. Scale bar represents 20 μm. Objective, × 40/0.75 NA. (D) Immunoperoxidase staining of bone marrow sections with antibodies to VWF or to gp130. Red staining for VWF is present in megakaryocytes (arrows) and sinusoidal endothelial cells (arrowheads) of both gp130^+/+/TCre mice and gp130^flox/flox/TCre mice. Staining for gp130 is present in megakaryocytes, a subset of other hematopoietic cells, and endothelial cells of gp130^+/+/TCre mice. By contrast, there is no staining for gp130 in hematopoietic or endothelial cells of gp130^flox/flox/TCre mice. Scale bar represents 50 μm. Data are representative of 3 to 4 independent experiments with 12-week-old mice. Objective, × 40/0.75 NA.