IL-1RI is expressed by cells in the E11 region aortic hematopoietic, endothelial, and mesenchymal cells. (A) Representative flow cytometric dot plots showing E11 aorta cells (n = 4) stained with antibodies specific for IL-1RI and CD45 (top panel) or c-kit (bottom panel). Percentages of cells in each quadrant are indicated; 3 to 3.6 × 104 events are shown, and more than 5 × 104 events were analyzed. (B) RT-PCR analysis for IL-1R and ligand expression in sorted HSCs (CD34+c-kit+), endothelial cells (CD45−VE-cadherin+; Endo), and presumed mesenchymal cells (CD45−VE-cadherin−; Mesen) from the E11 aorta. Glyceraldehyde-3-phosphate dehydrogenase (GAPDH) expression serves as the normalization control. −RT indicates no reverse transcriptase control. (C) Flow cytometric analysis of IL-1RI expression on UG26-1B6 stromal cells. X-axis indicates intensity of fluorescent signal from staining with IL-1RI–specific antibody; y-axis indicates the number of cells. (D) Intracellular flow cytometric dot plots showing control antibody (top panel) and anti–IL-1α antibody (bottom panel) staining in E11 AGM cells. Boxed areas indicate percentage positive cells.
