Figure 2. FIV(lacZ) injection (a total of 5 x 106 infectious particles) into the right TMJ resulted in widespread infection of hard as well as soft tissues of the joint. (A) Sagittal TMJ sections analyzed by ß-galactosidase immunohistochemistry and counter-stained by nuclear fast red revealed expression of the reporter gene lacZ in the hypertrophic zone of the condyle, comprised primarily of cartilaginous cells (B), as well as in the meniscus, endothelial cells, and perivascular osteocytes. Panel C depicts TMJ sections from a saline-injected animal. c = condyle; d = disk; m = muscle; v = vessel.