IFN-γ inhibits γHV68 infection of primary aortic cells. IFN-γ–treated and untreated intimal/adventitial and medial cultures were evaluated 3 days after infection. In c and d nuclei were stained blue, muscle actin was stained red, and viral antigen was stained green. Uninfected cultures and infected cultures stained with control Ab’s demonstrated no viral antigen staining. (a and b) Phase-contrast microscopy of infected intimal/adventitial cultures with or without IFN-γ. (c) Representative field of infected medial cultures without IFN-γ treatment. (d) Representative field of infected medial cultures treated with IFN-γ. (e) EM of a cell with nuclear capsids from an infected, untreated medial culture. (f) EM of a cell without nuclear capsids from an infected, IFN-γ–treated medial culture. (g) Multiple fields were evaluated by dual immunofluorescence for viral antigen and muscle actin (three experiments) or by electron microscopy (two experiments). IF, immunofluorescence. The numbers above the bars represent the number of cells counted. For comparing results with or without IFN-γ treatment by IF, ^AP < 0.005, ^BP < 0.0002. For comparing results with or without IFN-γ by EM, ^AP = 0.0024, ^BP = 0.0013.