Objective-Inflammatory processes play an important role in atherosclerosis, and increasing evidence implies that microbial pathogens and proinflammatory cytokines are involved in the development and activation of atherosclerotic lesions. To find new inflammatory genes, we explored the vascular transcriptional response to an activator of innate immunity bacterial lipopolysaccharides (LPSs). Methods and Results-Gene

Human cytomegalovirus (HCMV) infections in immunocompromised patients are associated with impaired immunological functions. Blood monocytes, which can differentiate into dendritic cells upon cytokine stimulation, play a central role in adequate immune reactivity and are believed to carry latent HCMV. We demonstrate here that HCMV infection of monocytes results in a block in the cytokine-induced differentiation of monocytes into functionally active CD1a-positive dendritic cells, which exhibited severely depressed immunological functions in vitro. The HCMV-infected cells exhibited a significantly reduced ability to endocytose fluorescein isothiocyanate-labeled dextran particles as well as a more than 90% reduced ability to migrate in response to the chemoattractant factors RANTES, MIP-1␣, and MIP-3␤. Interestingly, HCMV-infected cells expressed high levels of the costimulatory molecule CD86, in contrast to the low levels of expression that was observed on uninfected monocytes and uninfected immature dendritic cells. Furthermore, HCMV-infected CD1a-negative cells were unable to induce a T-cell response. Thus, these observations suggest that HCMV infection of monocytes in vitro blocks cytokine-induced dendritic cell differentiation, and since dendritic cells play a central role in initiating immune responses, these findings suggest a powerful tactic to avoid immune recognition and to blunt the immune response at early phases of infection.

All herpesviruses contain a ubiquitin (Ub)-specific cysteine protease domain embedded within their large tegument protein, based on homology with the corresponding sequences of UL36 from herpes simplex virus type 1 and M48 from murine cytomegalovirus. This type of activity has yet to be demonstrated for cells infected with a gammaherpesvirus. By activity-based profiling, we show that the large tegument protein of murine gammaherpesvirus (MHV-68) ORF64 (273 kDa) is a functional deubiquitinating protease, as assessed by tandem mass spectrometry of adducts in extracts from MHV-68-infected cells that had been labeled with ubiquitin vinylmethylester, a ubiquitin-based active site-directed probe. The recombinantly expressed aminoterminal segment of ORF64 displays deubiquitinating activity toward Ub C-terminal 7-amido-4-methylcoumarin in vitro. The findings reported here for MHV-68 ORF64 extend those made for the alpha-and betaherpesvirus families and are consistent with an important, conserved enzymatic function of the tegument protein.

Human cytomegalovirus (HCMV) infection in immunocompromised patients is associated with impaired immunological function. Blood monocytes, which differentiate into macrophage effector cells, are of central importance for immune reactivity. Here, we demonstrate that HCMV transiently blocks cytokine-induced differentiation of monocytes into functionally active phagocytic macrophages. In HCMV-treated cultures, the cells had classical macrophage markers but lacked the classical morphological appearance of macrophages and had impairments in migration and phagocytosis. Even at very low multiplicities of infection, macrophage differentiation was almost completely inhibited. The inhibition appeared to be mediated by a soluble factor released upon viral treatment of monocytes. Human immunodeficiency virus or measles virus had no such effects. These findings suggest that HCMV impairs immune function by blocking certain aspects of cytokineinduced differentiation of monocytes and demonstrate an efficient pathway for this virus to evade immune recognition that may have clinical implications for the generalized immunosuppression often observed in HCMV-infected patients.Human cytomegalovirus (HCMV), a member of the herpesvirus family, is an opportunistic pathogen that causes serious health problems in transplant recipients and in AIDS patients (5). It is associated with atherosclerosis, restenosis after coronary angioplasty, chronic rejection in organ transplant patients, and chronic graft-versus-host disease in bone marrow transplant recipients (15,28,51). After a primary infection, HCMV persists in a latent form, and an estimated 60 to 100% of the population carries the virus. In the latent phase, the viral genome exists in an episomal circular form (4) and does not replicate, enabling the virus to avoid immune recognition. Increasing evidence suggests that HCMV infection adversely affects both innate and adaptive immune responses. For example, HCMV reduces the expression of HLA class I and II molecules; inhibits antigenic processing, peptide presentation, and T-cell activation; confers resistance against natural killer cells; and interferes with the humoral immune response and cytokine-signaling events (reviewed in reference 26).Neutrophils are considered the major cell type carrying the virus during acute infection (11). However, monocytes are thought to be responsible for dissemination of the virus and are the predominant cell type harboring HCMV in the peripheral blood of seropositive individuals (54, 55). In CD14-positive monocytes, the HCMV genome is maintained at a relatively low copy number (6 to 13 copies/cell) (46). HCMV infection of monocytes is nonpermissive and restricted to early events of gene expression (9). The absence of late gene expression and virus production are consistent with the hypothesis that monocytes are reservoirs for latent virus. Although the virus cannot replicate in monocytes, HCMV-infected macrophages expressing late viral genes have been identified in tissue specimens from HCMV-infected pat...