Immunohistology of the subfornical organ (SFO) in the healthy SJL mouse. The top panel shows MECA-32+ capillaries within the SFO. Panels below demonstrate that ICAM-1 and VCAM-1 can not be detected on the MECA-32+ capillaries within the SFO. Single CD45+ perivascular cells can be detected within the SFO (open arrows, lower panel). Note the positive immunostaining for MECA-32 on choroid plexus capillaires and for ICAM-1 and VCAM-1 on the choroid plexus epithelium visible at the left and right margins (closed arrows). Immunoperoxidase, hematoxylin counterstain. Bar = 100 μm. This result was observed 10 times.