RESUMO
BACKGROUND: The Epstein-Barr virus (EBV) encodes two anti-apoptotic cellular Bcl2 homologs, BALF1 and BHRF1. BHRF1 has an anti-apoptotic activity but is rarely expressed in nasopharyngeal carcinoma (NPC). However, BALF1 is not yet well characterized. OBJECTIVES: The objective of the study was to characterize BALF1 gene. First, the search of its transcriptional expression in EBV-positive B cell lines, EBV-positive Burkitt's lymphoma's cell lines and nasopharyngeal carcinoma's biopsies. Second, the examination of its anti-apoptotic activity in serum dependent assays. STUDY DESIGN: We first analysed the transcriptional expression of BALF1 by reverse transcriptase DNA polymerase chain reaction (RT-PCR) method. For the analysis of its anti-apoptotic activity, we transfected NIH3T3 cells with pBABE-BALF1 expression plasmid and studied serum dependence of these transfectants. RESULTS: BALF1 expression was detected in the latent stage and increased more significantly during the lytic phase in IgG-treated AKATA and TPA-SB-treated P3HR1-TK negative cell lines. As its expression was not affected by the inhibitor of viral DNA synthesis, this gene does not belong to late gene family. When analysed its transcription in Burkitt's lymphoma (BL)-derived cell lines and NPC biopsies, all BL-derived cell lines and more than 80% of NPC biopsies transcribed this gene. The study of serum dependence of BALF1-transfected NIH3T3 cells showed: with 10% of serum, BALF1 transfectants grew significantly more higher cell density than vector alone transfected NIH3T3 cell lines and with 1% of serum, BALF1 transfectants were capable of growing, but with about 40% reduced rate in comparison with those with 10% serum, while vector alone transfected NIH3T3 cells could not almost grow. CONCLUSION: BALF1 gene was transcribed in EBV-associated tumor cells. BALF1 could render cells to serum independent. These results suggest that BALF1 gene could play its role in EBV oncogenesis.
Assuntos
Linfoma de Burkitt/virologia , Herpesvirus Humano 4/genética , Neoplasias Nasofaríngeas/virologia , Transcrição Gênica , Proteínas Virais/genética , Células 3T3 , Animais , Biópsia , Linfoma de Burkitt/genética , Divisão Celular , Linhagem Celular Tumoral , DNA Complementar/genética , DNA Viral/genética , Herpesvirus Humano 4/crescimento & desenvolvimento , Humanos , Camundongos , Neoplasias Nasofaríngeas/genética , RNA Viral/genética , Reação em Cadeia da Polimerase Via Transcriptase Reversa , TransfecçãoRESUMO
Virus specific IgM antibodies are very useful for the diagnosis of primer infection by the rubella and parotidis viruses. ELISA is the method usually used to detect IgM antibodies. The reactives and in some laboratories the apparatus are not always available. We carried out a serological method based on the immunocapture inhibition of hemagglutination of theses viruses by positive sera. 39 sera and 80 sera collected from patients and healthy population have been respectively studied to detect antirubella and antiparotidis IgM. The test appeared as sensitive and specific as the immunocapture IgM ELISA.
