The expression of ICAM-1 (CD54), beta 1 integrin (CD29), and CD44 on cytomegalovirus (CMV)-infected human embryonic fibroblasts (HEF) was analyzed by flow cytometry. The expression of these adhesion molecules increased significantly on CMV-infected HEF, on days 2 and 5 after inoculation, compared to uninfected HEF. However, the expression of these adhesion molecules decreased on herpes simplex virus (HSV)-1 and varicella-zoster virus (VZV)-infected HEF. Increased expression was not observed on HEF treated either with inactivated CMV or with supernatant fluid of CMV-infected cells. The addition of anti-cytokine (TNF-alpha, IL-1 beta, or IFN-gamma) antibodies had no effect on the increase of these adhesion molecules. This suggests that the increase in CD54, CD29, and CD44 on CMV-infected cells requires active virus replication and was not mediated by a soluble factor released from CMV-infected cells. Changes in adhesion molecules on CMV-infected fibroblasts may contribute to inflammation induced by CMV infection.