The entry of Epstein-Barr virus into B lymphocytes and epithelial cells during infection / 病毒学报

Epstein-Barr virus (EBV) is a human herpesvirus associated with important human diseases, including infectious mononucleosis syndrome, malignant lymphoma, and nasopharyngeal carcinoma. The mechanism of EBV entry into host cells remains a subject of intensive research. After decades of study, researchers have identified several key proteins and different patterns of EBV intrusion into host cells. The viral surface glycoproteins, gp350/220, gp42, gB, gH, and gL, are involved in interactions with the CR2 receptor on the surface of B lymphocytes during viral entry. However, the majority of epithelial cells lack CR2 receptor expression, which makes viral invasion much more complex than in B lymphocytes. Three different models have been proposed to explain how EBV enters epithelial cells: (1) "transfer of infection", mediated by B lymphocytes or Langerhans cells; (2) EBV utilizes its own proteins during the process of fusion with the cell membrane; and (3) progeny virions arising from EBV-infected epithelial cells cross lateral membranes into adjacent epithelial cells. This review will discuss the relevant mechanism of viral entry into B lymphocytes and epithelial cells during EBV infection.

Infectious Cloning Approach for Herpesvirus Based on Bacterial Artificial Chromosomes / 中国生物工程杂志

The genetic analysis of herpesviruses has been a constant challenge, due to the large, complex genomes of herpesviruses and mutagenesis of viral genes by conventional recombination methods in cell culture. Recently, a completely new approach for full-length infectious clones of herpesviruses based on bacterial artificial chromosomes (BACs) has been developed. This technique allows the maintenance, propagation and genetic modification of the viral genome as a BAC plasmid in E.coli, thus making the procedures fast, safe and effective in prokaryotic cells. This technique also makes it possible for the reconstitution of viral progeny or mutants by transfection of the BAC plasmid into eukaryotic cells, thereby facilitating the analysis of viral gene functions in the context of genome. In this presentation, Epstein-Barr virus was used as an example to describe the principle, establishment of the technique and mutation introduction into the BAC plasmid, and to discuss the perspective in the use of BAC-cloned herpesviruses.

Construction of recombinant fowlpox virus expressing chicken IL-2 and assay of biologic activity of the product in vitro / 生物工程学报

In order to determine the adjuvant effects of the chicken IL-2 (ChIL-2) on new generation vaccines, ChIL-2 gene was amplified from ConA-stimulated chicken spleen cells by RT-PCR and was directionally inserted into fowlpox virus (FPV) transferring vector p1175 under the control of FPV early/late promoter (PE/L), resulting in recombinant transferring vector p1175IL2. Then the p1175IL2 plasmid was transfected into chicken embryo fibroblasts (CEF) pre-infected with wild type FPV to generate recombinant fowlpox virus expressing ChIL-2 (rFPV-IL2). By selection of blue plaques on the CEF, overlaid with agar containing X-gal, rFPV-IL2 was obtained and purified. The supernatant from CEF monolayer infected with rFPV-IL2 (M.O.I2.0) after 72 hours was detected for the production of ChIL-2 by XTT/PMS colorimetric assay. About 3.6 x 10(5) u/mL of specific ChIL-2 activity was determined. The results show that rFPV-IL2 can express ChIL-2 effectively. rFPV-IL2 provides us with an effective tool for studying avian immunology as well as a potential vaccine-enhancing agent.