THY-1 Cell Surface Protein and Human Cytomegalovirus Infection

This research project is to investigate the role of a cell surface protein, THY-1, as an entry mediator for Human Cytomegalovirus (HCMV) infection. Previous research suggested that HCMV attaches to THY-1 on the host cell surface through virus encoded glycoprotein gB. The glycoproteins are located on the surface of virus particles thus initiating entry and infection. The specific question is to determine if the presence of a soluble form of THY-1 protein (sTHY-1) during the onset of infection would impair HCMV infectivity, based on the hypothesis that sTHY-1 would interrupt the interaction between the infectious virion and the target cells by competing with authentic cell surface THY-1 for binding to gB. The experimental approach is to prepare a plasmid encoding sTHY-1, to introduce it into mammalian cells by transfection to express the protein, to purify the sTHY-1, and to test the purified protein using Western blot and blocking of infection assays. HCMV is a herpes virus transmitted through saliva, urine, or other body fluids. Congenital HCMV occurs when HCMV is passed from a pregnant mother to her fetus. Many people encounter HCMV in their lifetime and according to the Centers for Disease Control (CDC), 50 to 80 percent of adults who are 40 or older are infected with HCMV. For individuals with a healthy immune system, HCMV produces mild illness, and for immunocompromised individuals, HCMV has a high rate of reactivation and can cause serious disease

Insulin Degrading Enzyme Induces a Conformational Change in Varicella-Zoster Virus gE, and Enhances Virus Infectivity and Stability

Varicella-zoster virus (VZV) glycoprotein E (gE) is essential for virus infectivity and binds to a cellular receptor, insulin-degrading enzyme (IDE), through its unique amino terminal extracellular domain. Previous work has shown IDE plays an important role in VZV infection and virus cell-to-cell spread, which is the sole route for VZV spread in vitro. Here we report that a recombinant soluble IDE (rIDE) enhances VZV infectivity at an early step of infection associated with an increase in virus internalization, and increases cell-to-cell spread. VZV mutants lacking the IDE binding domain of gE were impaired for syncytia formation and membrane fusion. Pre-treatment of cell-free VZV with rIDE markedly enhanced the stability of the virus over a range of conditions. rIDE interacted with gE to elicit a conformational change in gE and rendered it more susceptible to proteolysis. Co-incubation of rIDE with gE modified the size of gE. We propose that the conformational change in gE elicited by IDE enhances infectivity and stability of the virus and leads to increased fusogenicity during VZV infection. The ability of rIDE to enhance infectivity of cell-free VZV over a wide range of incubation times and temperatures suggests that rIDE may be useful for increasing the stability of varicella or zoster vaccines