Abstract
Epstein-Barr virus (EBV) induces CD95 expression and the CD95 gene (FAS) is regulated by NF-kappaB, STAT1, and/or p53. To understand the contribution of these factors in the regulation of CD95 by EBV in lymphoblastoid cell lines (LCLs), we cloned dominant-active IkappaBalpha, active (STAT1alpha) and inactive (STAT1beta) forms of STAT1, p53, a dominant-negative mutant of LMP1, and wild-type LMP1 into a novel double-inducible episomal vector, pRT-1. These plasmids were stably transfected either into wild-type LCLs or EREB2-5 cells, an LCL with an estrogen-regulatable EBNA2 protein. Inhibition of LMP1 signaling decreased expression of CD95, whereas overexpression of LMP1 markedly increased it. Induction of the latency III program in EREB2-5 cells correlated with activation of NF-kappaB, STAT1, and p53. CD95 expression was regulated by these 3 transcriptional systems. STAT1 and p53 activation were secondary to NF-kappaB activation. CD95 surface expression sensitized EBV-infected B cells to the induction of CD95-mediated apoptosis. In vitro inhibition of CD95-CD95 ligand interaction was found to reverse T-cell killing of EBV-infected B cells. Therefore, LMP1 activation of NF-kappaB sensitizes infected B cells to CD95-mediated apoptosis and renders EBV latency III-immortalized B cells susceptible to elimination by the immune system, contributing to the establishment of a host/virus equilibrium.
Publication types
-
Research Support, Non-U.S. Gov't
MeSH terms
-
Animals
-
Apoptosis* / drug effects
-
Apoptosis* / genetics
-
B-Lymphocytes / metabolism*
-
B-Lymphocytes / virology
-
Cell Line, Tumor
-
Cell Transformation, Viral* / drug effects
-
Cell Transformation, Viral* / genetics
-
Epstein-Barr Virus Infections / genetics
-
Epstein-Barr Virus Infections / metabolism*
-
Epstein-Barr Virus Infections / virology
-
Epstein-Barr Virus Nuclear Antigens / genetics
-
Epstein-Barr Virus Nuclear Antigens / metabolism
-
Estrogens / pharmacology
-
Fas Ligand Protein
-
Gene Expression Regulation / drug effects
-
Genes, Dominant / genetics
-
Genetic Vectors / metabolism
-
Herpesvirus 4, Human / metabolism*
-
Humans
-
I-kappa B Proteins / genetics
-
I-kappa B Proteins / metabolism
-
Interferon-Stimulated Gene Factor 3 / genetics
-
Interferon-Stimulated Gene Factor 3 / metabolism
-
Membrane Glycoproteins / metabolism
-
Mutation
-
NF-KappaB Inhibitor alpha
-
NF-kappa B / metabolism
-
Plasmids / genetics
-
Plasmids / metabolism
-
Signal Transduction* / drug effects
-
Signal Transduction* / genetics
-
T-Lymphocytes / metabolism
-
T-Lymphocytes / virology
-
Tumor Necrosis Factors / metabolism
-
Tumor Suppressor Protein p53 / genetics
-
Tumor Suppressor Protein p53 / metabolism
-
Viral Matrix Proteins / genetics
-
Viral Matrix Proteins / metabolism
-
Viral Proteins
-
fas Receptor / biosynthesis
Substances
-
EBNA-2 protein, Human herpesvirus 4
-
EBV-associated membrane antigen, Epstein-Barr virus
-
Epstein-Barr Virus Nuclear Antigens
-
Estrogens
-
FASLG protein, human
-
Fas Ligand Protein
-
I-kappa B Proteins
-
Interferon-Stimulated Gene Factor 3
-
Membrane Glycoproteins
-
NF-kappa B
-
NFKBIA protein, human
-
Tumor Necrosis Factors
-
Tumor Suppressor Protein p53
-
Viral Matrix Proteins
-
Viral Proteins
-
fas Receptor
-
gamma interferon activation factor
-
NF-KappaB Inhibitor alpha