Incidence and severity of chronic elastic arteritis in wild-type mice infected with high doses of γHV68 with or without transient depletion of IFN-γ. Mice were infected with the indicated doses of γHV68 with or without depletion of IFN-γ and evaluated for arteritis on H&E-stained sections 5.5 to 10 weeks after infection. (a) The incidence of arteritis in various groups is presented. Seven of 19 mice infected with 17 to 20 × 10⁷ PFU γHV68 died within 7 days. Twelve of 14 mice infected with 34 to 50 × 10⁷ PFU died within 7 days. Data for transient depletions are from two independent experiments. Data for no depletions are from 4–5 independent experiments. ^AP = 0.0062; ^BP = 0.0043. (b) Lesion at the aortic base of a 129Ev/Sv mouse sacrificed 10 weeks after infection with 10⁸ PFU γHV68. Lesions in transiently IFN-γ–depleted 129Ev/Sv mice have similar histology (lesion scores for 25 mice from both groups combined = 2.0 ± 0.2; P < 0.0001 for scores compared with IFN-γR^–/– mice, P = 0.001 compared with chronically depleted wild-type mice). (c) High-power view of boxed region in b. (d) Lesion at the aortic base of a chronically IFN-γ–depleted 129Ev/Sv mouse sacrificed 6 weeks after infection with 5 × 10⁷ PFU γHV68 (lesion scores for four mice = 4.0 ± 0.7). Arteritis in IFN-γR^–/– mice has similar histology (lesion scores for 16 mice = 5.0 ± 0). (e) High-power view of boxed region in d. The black lines show the boundaries of the media. Adv, adventitia; M, media; I, intima; L, lumen; V, aortic valve. ND, not determined.