INITIATION OF CELL INFECTION BY EPSTEIN-BARR VIRUS

EB病毒（EBV）最为人所知的是其通过使B淋巴细胞永生化而感染并引起疾病的能力。 然而，病毒也会进入上皮细胞，造成毁灭性的后果。 它与鼻咽癌的发展密切相关，并可能在某些胃癌的出现中发挥作用。 本研究的长期目标是了解EBV组织嗜性的分子基础。大多数人都知道EBV如何进入B细胞。 目前的模型提出，病毒最低限度地使用与补体受体2型（CR2）结合的附着蛋白gp 350/220和参与穿透的三种糖蛋白gH-gL-gp 42的复合物。 成功的穿透需要gp 42与作为B细胞表面辅助受体的HLA II类结合。 进入上皮细胞是非常不同的。 目前的上皮细胞模型提出，进入既不需要使用CR2，也不需要gp 42和HLA II类之间的相互作用。 相反，新的发现表明上皮细胞上存在一种新的受体和一种新的辅助受体。 这个应用程序的直接目标是测试这些模型的四个具体目标。 第一个目标是鉴定使缺乏gp 42的病毒能够感染上皮细胞的辅助受体。第二个目的是探索和比较gH复合物与B细胞和上皮细胞的相互作用。 第三个目标是鉴定EBV用于附着于CR2阴性上皮细胞的病毒糖蛋白。 最终目的是确定EBV感染CR2阴性上皮细胞所用的受体。受体和辅助受体的鉴定将通过用上皮细胞cDNA表达文库筛选适当的细胞来解决。 将用缺乏gp 42或表达绿色荧光蛋白的重组病毒探测转染的细胞。 将通过突变分析和缺乏gH的病毒的互补来探索细胞与gH复合物的相互作用。 缺乏多种糖蛋白的重组蛋白、抗体和病毒将用于鉴定上皮细胞附着蛋白。 解剖使EBV能够进入其感染的细胞的分子事件对于理解这种重要的人类病原体的生物学至关重要。

Epstein-Barr virus (EBV) is best known for its ability to infect and cause disease by immortalizing B lymphocytes. However, the virus also accesses epithelial cells with devastating consequences. It is strongly implicated in the development of nasopharyngeal carcinoma and may play a role in the emergence of certain gastric cancers. The long term goal of this research is to understand the molecular basis for the tissue tropism of EBV. Most is known about how EBV enters B cells. A current model proposes that virus uses minimally an attachment protein gp350/220 which binds to the complement receptor type 2 (CR2) and a complex of three glycoproteins gH-gL-gp42 which is involved in penetration. Successful penetration requires that gp42 bind to HLA class II which functions as a coreceptor on the B cell surface. Entry into epithelial cells is very different. A current model for epithelial cells proposes that entry requires neither use of CR2 nor an interaction between gp42 and HLA class II. Instead, new findings suggest the existence of both a novel receptor and a novel coreceptor on epithelial cells. The immediate goal of this application is to test these models with four specific aims. The first aim is to identify the coreceptor that enables a virus that lacks gp42 to infect epithelial cells. The second aim is to explore and compare the interactions of the gH complex with B cells and epithelial cells. The third aim is to identify the viral glycoprotein used by EBV to attach to CR2- negative epithelial cells. The final aim is to identify the receptor used by EBV to infect CR2-negative epithelial cells. Identification of receptor and coreceptor will be addressed by transfecting appropriate cells with epithelial cell cDNA expression libraries. Transfected cells will be probed with recombinant viruses lacking gp42, or expressing green fluoroscent protein. Interactions of cells with the gH complex will be explored by mutational analysis and complementation of virus lacking gH. Recombinant proteins, antibodies and viruses lacking a variety of glycoproteins will be used to identify the epithelial cell attachment protein. Dissection of the molecular events that enable EBV to access the cells it infects is critical to understanding the biology of this important human pathogen.