Entry of Epstein-Barr virus into lymphocytes and epithelial cells
Entry of Epstein-Barr virus into lymphocytes and epithelial cells
Miller, Nancimae. University of Florida, 1991. 1991. 9202038.
Abstract (summary)
Translate Abstract
Epstein-Barr virus (EBV) is a human herpesvirus which causes infectious mononucleosis and is associated with two cancers, Burkitt's lymphoma and nasopharyngeal carcinoma. To understand the biologic activity of EBV, it is crucial to understand how EBV infects cells, and what viral components are important to this process. Epstein-Barr virus infects two cell types, B lymphocytes and epithelial cells. To examine the early events in virus infection, binding and fusion, we have adapted an assay that measures membrane fusion. Virus membranes were labeled with concentrations of octadecylrhodamine (R$\sb{18}$) or 5-(N-octadecanoyl)aminofluorescein (AF) at which fluorescence is self-quenched. The fluorescence of AF is also sensitive to changes in pH. Fusion and mixing of virus and cell membranes was measured in terms of relief of self-quenching and was monitored kinetically.
The assay was used to compare virus fusion with lymphoblastoid cell lines, lymphocytes recently transformed with EBV, normal B lymphocytes and epithelial cells. Entry of EBV into all cell types occurred independent of exposure to low pH. However, virus fusion with normal and recently transformed lymphocytes occurred from within endocytic vesicles, whereas fusion with lymphoblastoid and epithelial cells occurred at the plasma membrane.
The contribution to fusion made by virus envelope proteins to fusion was studied with monoclonal antibodies that neutralized virus infectivity. Antibody to glycoprotein gp85 inhibited fusion with all cells except epithelial cells. Antibody to glycoprotein gp350, responsible for virus attachment to CR2 on lymphocytes, only partially inhibited virus binding to epithelial cells and the remaining bound virus did not fuse. Soluble CR2 inhibited virus binding to lymphocytes but only partially inhibited binding to epithelial cells.
These studies document clear differences between virus entry into lymphocytes and epithelial cells and suggest that the virus proteins involved in fusion with the two cell types may be distinct.
