Cytokine induction after Epstein-Barr virus infection of peripheral T-lymphocytes in vitro

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.

Detection of IgM specific antibody using indirect immunofluorescent assay for diagnosis of acute leptospirosis.

Leptospirosis is a worldwide zoonosis, caused by Leptospira interrogans. At the earlier stage of the disease, the IgM immunoassays are expected to have more sensitivity than other immunoassays. Previous reports showed that the indirect immunofluorescent assay for detection of immunoglobulins (IFA-Igs) against Leptospira spp showed higher sensitive and specific than some genus specific tests. The authors determined an efficacy of the indirect immunofluorescent assay for detection of IgM specific leptospiral antibody (IFA-IgM). One hundred and eighty patients with acute febrile illness without localizing signs admitted to Hat Yai Hospital were studied. Using the cut-off value of > or = 1:400, the overall sensitivity, and overall specificity of the IFA-IgM were 89.2 per cent and 95.1 per cent, respectively. They were slightly greater than those of the conventional IFA-Igs (86.5% and 91.6%). The first sera obtained from patients including acute sera and single sera showed a low sensitivity (32.4%) but still higher than the IFA-Igs (29.7%). None of the patients with various diseases commonly confused with leptospirosis or healthy blood donors gave a titer greater than 1:200. In conclusion, the IFA-IgM has the same protocol as the IFA-Igs but the sensitivity and specificity is slightly greater than the IFA-Igs. This is another alternative test for the diagnosis of acute leptospirosis.