Quantitation of clearance of γHV68 from different vascular structures over time. IFN-γR^–/– mice were infected and analyzed as in Figure 1 at days 7, 9, 11, 13, 15, 17, 19, 21, 42, and 43 after infection. n, number of mice. The number of aortas with blue staining in the adventitia (Adv) or media (M) is reported for the aortic base (a) or the descending aorta (b), which was representative of the entire aorta. Staining of a peripheral vessel on the posterior surface of both kidneys is also reported (c). For staining at late times compared with staining at days 7–15, ^AP < 0.0001; ^BP > 0.05; ^CP = 0.04. For medial clearance compared with adventitial clearance, ^DP < 0.0001; ^EP = 0.006; ^FP = 0.1.