Epstein-Barr Virus Enhances Cancer-Specific Aberrant Splicing of TSG101 Pre-mRNA

Tumor viruses gain control of cellular functions when they infect and transform host cells. Alternative splicing is one of the cellular processes exploited by tumor viruses to benefit viral replication and support oncogenesis. Epstein-Barr virus (EBV) participates in a number of cancers, as reported mostly in nasopharyngeal carcinoma (NPC) and Burkitt lymphoma (BL). Using RT-nested-PCR and Northern blot analysis in NPC and BL cells, here we demonstrate that EBV promotes specific alternative splicing of TSG101 pre-mRNA, which generates the TSG101∆154-1054 variant though the agency of its viral proteins, such as EBNA-1, Zta and Rta. The level of TSG101∆154-1054 is particularly enhanced upon EBV entry into the lytic cycle, increasing protein stability of TSG101 and causing the cumulative synthesis of EBV late lytic proteins, such as VCA and gp350/220. TSG101∆154-1054-mediated production of VCA and gp350/220 is blocked by the overexpression of a translational mutant of TSG101∆154-1054 or by the depletion of full-length TSG101, which is consistent with the known role of the TSG101∆154-1054 protein in stabilizing the TSG101 protein. NPC patients whose tumor tissues express TSG101∆154-1054 have high serum levels of anti-VCA antibodies and high levels of viral DNA in their tumors. Our findings highlight the functional importance of TSG101∆154-1054 in allowing full completion of the EBV lytic cycle to produce viral particles. We propose that targeting EBV-induced TSG101 alternative splicing has broad potential as a therapeutic to treat EBV-associated malignancies.

A single epitope of Epstein-Barr Virus stimulate IgG production in mice

Background

Epstein-Barr virus (EBV) is closely associated with the high incidence of nasopharyngeal carcinoma in worldwide. Vaccination is one strategy with the potential to prevent the occurrence of EBV-associated cancers, but a suitable vaccine is yet to be licensed. Much vaccine development research focuses on the GP350/220 protein of EBV as it contains an immunogenic epitope at residues 147–165, which efficiently stimulates IgG production in vitro. We examined the ability of this epitope (EBVepitope) to induce IgG production in mice.

Methods

The antibody binding pattern of the epitope was analyzed using bioinformatics tools. The IgG production in mice were examined by FACS Calibur™ Flow cytometer.

Results

The epitope bound the 72A1 monoclonal antibody at the same site as GP350/220 protein, indicating that the epitope should stimulate B cells to produce antibody. Moreover, in vivo administration of EBVepitope successfully induced IgG expression from B cells, compared with controls. Further investigation indicated that the relative number of B cells expressing IgE in EBVepitope-treated mice was lower than controls.

Conclusions

Our data suggest that this EBV GP350 epitope is able to induce IgG expression in vivo without causing allergic reactions, and represents a potential EBV vaccine candidate.

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Single EBV epitope adequate stimulate production of IgG in Mice.

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EBVepitope has similarity structure and binding pattern on Antibody compare with GP350/220 protein.

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EBVepitope does not stimulate IgE production in Mice.

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EBVepitope is warrant for further investigation to develop safe EBV vaccine.

Epitope mapping of gp350/220 conserved domain of epstein barr virus to develop nasopharyngeal carcinoma (npc) vaccine

Nasopharyngeal carcinoma (NPC) is a malignant tumor in the nasopharyngeal epithelial cells that caused by many factors, one of which is the viral infection of EBV (Epstein Barr Virus). The standard treatments to cure NPC still have not been encouraging. The prevention through vaccination is an effective way to stop the disease. However, EBV vaccine being able to cover all variants of virus is still not available yet. Therefore, we identified the conserved region of glycoprotein 350/220 of EBV which has immunogenic and antigenic properties. The glycoprotein 350/220 is viral surface protein responsible to bind CR2 receptor, mediated EBV to enter the host cell. The conserved domain is crucial for EBV in infecting host cells. Further, by blocking CR2 binding domain of gp350/220 using antibody will inhibit EBV's spreading, and provoke an immune system to eliminate the virus in a patient. Glycoprotein 350/220 from all variants of Epstein-Barr virus was retrieved from NCBI. The conserved domain of gp350/220 was identified by aligning the protein sequences and structures. The polymorphic structure was used as a template for docking analysis to identify the resemblance of amino acid from polymorphic variants of gp350/220 that binds CR2. The epitope mapping of gp350/220 was done by Discotope BepiPred method. The result revealed that the conserved region of gp350/220 was predicted to have an epitope, QNPVYLIPETVPYIKWDNC residue, and it does not have any similarities to the human's cell surface protein. Therefore, it can be used as a reference to develop vaccine to prevent NPC.