Human cytomegalovirus (HCMV) is a ubiquitous herpesvirus, for which there is no vaccine or cure. This viral infection, once acquired, is life-long, residing latently in hematopoietic cells. However, latently infected individuals with weakened immune systems often undergo HCMV reactivation, which can cause serious complications in immunosuppressed and immunocompromised patients. Current anti-viral therapies target late stages of viral replication, and are often met with therapeutic resistance, necessitating the development of novel therapeutics. In this current study, we identified a naturally occurring flavonoid compound, deguelin, which inhibits HCMV lytic replication. Our findings reveal that nanomolar concentrations of deguelin significantly suppress the production of infectious virus. Further, we show that deguelin inhibits the lytic cycle during the phase of the replication cycle consistent with early (E) gene and protein expression. Importantly, our data reveal that deguelin inhibits replication of a ganciclovir-resistant strain of HCMV. Together, our findings identify a novel, naturally occurring compound that may prove useful in the treatment of HCMV replication.

Propagation of human cytomegalovirus (CMV) in cultured cells results in genetic adaptations that confer improved growth in vitro and significant attenuation in vivo. Mutations in RL13 arise quickly during cell culture passage, while mutations in the UL128-131A locus emerge later during fibroblast passage and disrupt expression of a glycoprotein complex that is important for entry into epithelial and endothelial cells. As in vivo CMV replicates in the context of host antibodies, we reasoned that antibodies might mitigate the accumulation of adaptive mutations during cell culture passage. To test this, CMV in infant urine was used to infect replicate fibroblast cultures. One lineage was passaged in the absence of CMV-hyperimmuneglobulin (HIG) while the other was passaged with HIG in the culture medium. The former lost epithelial tropism and aquired mutations disrupting RL13 and UL131A expression, whereas the latter retained epithelial tropism and both gene loci remained intact after 22 passages. An epitheliotropic RL13+/ UL131A+ virus was isolated by limiting-dilution in the presence of HIG and expanded to produce a working stock sufficient to conduct cell tropism experiments. Thus, culture in the presence of antibodies may facilitate in vitro experiments using viruses that are genetically more authentic than has been previously possible.

The majority of adults in the world (around 83%) carry antibodies reactive with HCMV and are thought to retain inactive or latent infections lifelong. The virus is transmitted via saliva so infection events are likely to be common. Indeed it is hard to imagine a life without exposure to HCMV. From 45 seronegative individuals (13 renal transplant recipients, 32 healthy adults), we present seven cases who had detectable HCMV DNA in their blood and/or saliva, or a CMV-encoded homologue of IL-10 (vIL-10) in their plasma. One case displayed NK cells characteristic of CMV infection, and HCMV DNA became undetectable. In other cases, the infection may persist with seroconversion blocked by vIL-10. Future research should seek mechanisms that can prevent an individual from seroconverting despite a persistent HCMV infection, as HCMV vaccines may not work well in such people.

It has recently been discovered that mere cell contact by human cytomegalovirus (CMV) particles leads to profound modulation of cellular gene expression. Reduced monocyte human leukocyte antigen (HLA-DR) expression is a novel biomarker of severity and outcome in many diseases. Modulation of CD14 protein by CMV was shown in vitro, but little is known about the phenomenon in vivo (during active cytomegalovirus disease). Therefore, we investigated monocyte CD14 and HLA-DR expression in CMV infected patients in relation to logarithmic phase of infectious process. Samples from patients with active CMV replication (exponential growth of CMV viremia) were tested. After CD45/SSC gating monocyte CD14 and HLA-DR expression were determined by double-color flow-cytometry. Significant monocytosis and poor correlation between CMV replication and CD14+HLA-DR(-) cells prompted CD14 investigation. During logarithmic phase of CMV infection increased count and percentage of CD14low monocytes were observed which correlated with viral replication in several clinical situations except when there was a rapid recovery without relapse. Furthermore, most of CD14low monocytes are HLA-DR+. The increase of CD14low monocytes is also observed under the influence of high dose of glucocorticoids (20 mg of dexamethasone). The reduction in CD14 induced by CMV and dexamethasone indicates that the monocyte balance is disturbed between the classical and non-classical phenotype. A high percentage of CD14lowHLA-DR+ probably gives rise to adaptive and a decrease of innate immune response. In light of the logarithmic increase of viral load (with exponent between 3,23 and 5,77), high monocytosis above 1200 / µl is a hallmark of CMV replication.

Background Cytomegalovirus (CMV) is a major pathogen that cause remarkable rate of morbidity and mortality, especially in immunocompromised patients. It is important to find risk factors associated with CMV viremia. We studied the differences in CMV seropositivity in relation to liver function biomarkers in male and female Saudi population in an attempt to understand the variation in the CMV seroprevalence with sex and find the risk factor to develop liver dysfunction or hepatocellular carcinoma. Material and subjects: The CMV- IgG and IgM were screened in serum samples of 150 non- A-G hepatities patients with elevation of liver profiles (ALT, AST, ALP and GGT) and categorized as males and females. Samples were collected from different general hospitals and polyclinic in KSA from March 2014 to June 2015. A correlation between CMV seropositivity measured with both antibodies and liver enzymes were tested. Receiver operating characteristics (ROC) analysis and multiple regressions were done for the obtained data. Results: Our study shows that females had much higher IgG and IgM compared to age-matching males. A significant correlation between both antibodies and liver enzymes (AST, ALT) was recorded. Less significant correlation of both IgG and IgM with GGT was also observed. Receiver operating characteristics (ROC) analysis revealed that both IgG and IgM can be used as excellent predictive markers for CMV infection as both recorded 100% specificity and sensitivity together with area under the curve of 1 in males and females. Multiple regression analysis ascertain the correlation between both antibodies as dependent variables and liver enzymes as independent variables with ALT being the most affected enzyme with CMV seropositivity especially in females. Conclusion:he data discussed above This study shows that CMV is capable of initiating and accelerating liver dysfunction in both sexes. The high seroprevalence in females at reproductive age is especially important as they can transmit the virus to their developing fetus. Prevention of CMV infection in young girls 11-14 years old, through counseling on hygiene or possible future vaccination, may lead to a decrease of congenital CMV infections with the concomitant risk of developing liver dysfunction or hepatocellular carcinoma. Keywords: Cytomegalovirus, Alanine transaminase, Aspartate transaminase Alkaline phosphatase, γ-Glutamyltranspeptidase, liver function.

Human Cytomegalovirus (HCMV) infection is a serious complication in hematopoietic stem cell transplant (HSCT) recipients due to virus-induced myelosuppression and impairment of stem cell engraftment. Despite the clear clinical link between myelosuppression and HCMV infection, little is known about the mechanism(s) by which the virus inhibits normal hematopoiesis because of the strict species specificity and the lack of surrogate animal models. In this study, we developed a novel humanized mouse model system that recapitulates the HCMV-mediated engraftment failure after hematopoietic cell transplantation. We observed significant alterations in the hematopoietic populations in peripheral lymphoid tissues following engraftment of a subset of HCMV+ CD34+ HPCs within the transplant suggesting that a small proportion of HCMV-infected CD34+ HPCs can profoundly affect HPC differentiation in the bone marrow microenvironment. This model will be instrumental to gain insight into the fundamental mechanisms of HCMV myelosuppression after HSCT and provides a platform to assess novel treatment strategies.

The past few years have brought substantial progress toward understanding how human cytomegalovirus (HCMV) enters the remarkably wide spectrum of cell types and tissues that the virus infects. Neuropilin-2 and platelet-derived growth factor receptor alpha (PDGFRa) were identified as receptors, respectively, for the trimeric and pentameric glycoprotein H/glycoprotein L (gH/gL) complexes that in large part govern HCMV cell tropism, while CD90 and CD147 were also found to play roles during entry. X-ray crystal structures for the proximal viral fusogen, glycoprotein B (gB), and for the pentameric gH/gL complex (pentamer) have been solved. A novel virion gH complex consisting of gH bound to UL116 instead of gL was described, and findings supporting the existence of a stable complex between gH/gL and gB were reported. Additional work indicates that the pentamer promotes a mode of cell-associated spread that resists antibody neutralization, as opposed to the trimeric gH/gL complex (trimer), which appears to be broadly required for the infectivity of cell-free virions. Finally, viral factors such as UL148 and US16 were identified that can influence the incorporation of the alternative gH/gL complexes into virions. We will review these advances and their implications for understanding HCMV entry and cell tropism.

As a universal pathogen leading to neonatal defects and transplant failure, Human cytomegalovirus (HCMV) has strict species specificity that the inability to using this virus in animals has hampered its pathogenesis study. However, the mechanism of cross-species barrier remains elusive that no non-human cell model has been established to fill this knowledge gap. We observed that primary dermis fibroblasts (TSDF) isolated from the Chinese tree shrew (Tupaia belangeri chinensis), a small laboratory animal with close affinity to primates, were permissive to HCMV replication. In TSDF infected with GFP-expressing HCMV, the green fluorescence and cytopathic effect were observed and the expression of 3 kinetic genes and replication of viral genome were detected. The cell-free viruses produced in TSDF reached 103 pfu/mL at 96 hpi, which were 10-fold lower than in primary human foreskin fibroblasts. Our results demonstrated that TSDF supported low level of lytic replication of HCMV. The TSDF model provides a useful platform for the mechanism study of species barrier of HCMV.

Human cytomegalovirus (HCMV) is a β-herpes virus that is a significant pathogen within immune compromised populations. HCMV morbidity is induced through viral dissemination and inflammation. Typically, viral dissemination is thought to follow Fenner’s hypothesis where virus replicates at the site of infection, followed by replication in the draining lymph nodes, and eventually replicating within blood filtering organs. Although CMVs somewhat follow Fenner’s hypothesis, they deviate from it by spreading primarily through innate immune cells as opposed to cell free virus. Also, in vivo CMVs infect new cells via cell to cell spread and disseminate directly to secondary organs through novel mechanisms. We review the historic and recent literature pointing to CMV’s direct dissemination to secondary organs and the genes that it has evolved for increasing its ability to disseminate. We also highlight aspects of CMV infection for studying viral dissemination when using in vivo animal models.

Herpesviruses usurp cellular stress responses to avoid immune detection while simultaneously promoting viral replication and spread. The unfolded protein response (UPR) is an evolutionarily conserved stress response that is activated when the protein load in the ER saturates its chaperone folding capacity causing an accrual of misfolded proteins. Through translational and transcriptional reprogramming, the UPR aims to restore protein homeostasis; however, if this fails the cell undergoes apoptosis. It is commonly thought that many enveloped viruses, including herpesviruses, may activate the UPR due to saturation of the ER with nascent glycoproteins and thus these viruses may have evolved mechanisms to evade the potentially negative effects of UPR signaling. Over the past fifteen years there has been considerable effort to provide evidence that different viruses may reprogram the UPR to promote viral replication. Here we provide an overview of the molecular events of UPR activation, signaling and transcriptional outputs, and highlight key findings that demonstrate that the UPR is an important cellular stress response that herpesviruses have hijacked to facilitate persistent infection.

Although the existing paradigm states that CMV reactivation is under control of cellular immune response, the role of humoral counterpart is underestimated. Anti-CMV positive woman after conditioning with Bu-Flu-ATG underwent stem cell transplantation from fully matched, seronegative sibling donor. In immunodeficient recipient fast and significant decrease of specific immune response was observed but reconstitution of marrow-derived B and NK cells was prior thymic origin T cells. The lowest CMV-IgG(89 U/ml) was observed just before CMV viremia. Noteworthy, the sole and exclusive factor of CMV-specific immune response is a residual recipient antibody class IgG. The CMV-quantiferon increase was observed later, but in the first phase immune reconstitution of the PHA-induced IFNγ release was significantly lower than that CMV-induced. It corresponds with NK cells increase at the top of lymphocyte reconstitution and undetected CMV-specific CD8 cells by pentamer technique. Most of NK cells are CD16+, thus are stimulated by residual IgG. In immunocompetent donor the cellular and humoral immune response increases in parallel manner but symptoms of CMV mononucleosis were observed till the increase of specific IgG. Our observations shed light on a unique host-CMV interaction: indicate that significant decrease of CMV-IgG is a good predictor for CMV reactivation during secondary immunodeficiency.