ABSTRACT
Background: There are few reports about the interactions of EBV with peripheral T-cells, especially during the early phase of infection. Objective: Demonstrate the capability of EBV to infect and replicate in human peripheral T-cells in vitro. Methods: After treating with EBV, the susceptibility of in vitro EBV infection into T-cells was confirmed using electron microscopy, the expression of EBV mRNA using RT-PCR, and the expression of EBV proteins using Western blot analysis. The expression of CD19 and CD21 mRNA was determined using RT-PCR. The induction of cell death was measured using trypan blue exclusion assay. Results: The susceptibility of in vitro EBV infection was confirmed by the presence of virus particles in the cytoplasm. The entering to lytic infection was confirmed by detection the expression of EBV lytic (BZLF1) mRNA, and the expression of late lytic proteins (VCA and gp350/220). The expression of CD19 and CD21 were not observed using RT-PCR. The interactions of EBV with T-cells leaded to induction of T-cell death. Conclusion: Peripheral T-cells are a direct target of EBV infection. At the beginning of infection by EBV, EBV infection of T-cells leads to the entering into lytic virus replication. EBV binds to these cells through a receptor distinct from the CD21.
ABSTRACT
Background: Although the presence of Epstein-Barr virus (EBV) in different T-cell malignancies has been widely reported, there is very few data available for EBV infection of normal T cells. This leads to the lack of knowledge on the early events after T cell infection. Objective: Investigate the early events occurring after normal human peripheral T-cells are infected with EBV in vitro. Methods: T-cells were treated with EBV in vitro. The expression of tumor necrosis factor- α (TNF-α) mRNA were determined using reverse-transcription (RT)-PCR, and the level of TNF-α and interferon- γ (IFN-γ) in the culture supernatant were measured using ELISA. The effect of virus inactivation on cytokine induction from T-cells was also determined. Results: At the beginning of T cell infection by EBV, the expression of several lytic EBV transcripts (BALF5, BcLF1, and BLLF1) were observed using RT-PCR. This indicated the susceptibility of in vitro EBV infection and the entering lytic cycle of EBV-infected T-cells. The interactions of EBV with T-cells lead to induction of inflammatory cytokines, tumour necrosis factor- α (TNF-α) and interferon- γ (IFN-γ), production from the T-cells. Inactivation of the virus by UV irradiation eliminated the TNF-α and IFN-γ induction by EBV, suggesting the involvement in the expression of viral gene(s). Conclusion: This in vitro analysis demonstrated the cytokine induction by EBV after primary infection of T-cells.