Pericytes express receptors for TNF and IL-1β. (A) The panels show a 3D-reconstruced postcapillary venule of an unstimulated cremaster muscle immunostained for PECAM-1 (EC junction, blue), αSMA (pericytes, red), and the cytokine receptor of interest (green) or with an isotype control antibody (top). A 1-µm-thick section of the dotted boxed region is enlarged below highlighting the specific expression of TNFRI, TNFRII, and IL-1RI on both ECs (black arrows) and pericytes (arrowhead). Bars, 10 µm. (B) Graphs show the MFI of TNFRI-, TNFRII-, or IL-RI–specific staining on ECs (left) and pericytes (right) as determined by IMARIS software. Significant expression of the cytokine receptors as compared with the binding of an isotype control antibody (Student’s t test) is indicated by asterisks. ***, P < 0.001. (C) Representative flow cytometry histograms illustrate the presence of TNFRI, TNFRII, and IL-1RI on C3H/10T1/2 cells in vitro. Binding of isotype control antibodies (back lines) and primary mAbs directed against cytokine receptors (blue line) are shown as overlays. The graph (bottom right) shows mean RFIs for TNFRI, TNFRII, and IL-1RI. The dotted line indicates the isotype control RFI. Significant differences compared with the isotype control (Student’s t test) are indicated by asterisks. *, P < 0.05; ***, P < 0.001. Representative images and results are from n = 4 mice (A and B; at least 3 vessels per mouse) and 6 (C) experiments.