Characterization of HeLa cells persistently infected with influenza virus B/Lee/40 with respect to telomerase activity and apoptosis.
OBJECTIVE
The purpose of this study was to examine telomerase activity and apoptotic changes in HeLa cells persistently infected with influenza viruses B/Lee/40 (He/Le cells).


METHODS
He/Le cells were established as described previously [Intervirology 2002;45:67-70], and passaged twice a week. The existence of influenza virus genes was monitored by the reverse transcription polymerase chain reaction (RT-PCR). Telomerase activities in He/Le cells were assayed by Telochaser (stretch PCR method). Apoptotic changes in He/Le cells were examined using the Apoptotic DNA Ladder Kit and the In situ Cell Death Detection Kit, Fluorescence.


RESULTS
In He/Le cells, (1) all eight influenza virus genes were detected by RT-PCR until 62 days post infection (p.i.); (2) only nucleoprotein gene remained detectable until 120 days p.i.; (3) telomerase activity of He/Le cells normalized to those of uninfected HeLa cells was remarkably decreased (16-55% of control) during the persistence of influenza and recovered up to 80% of control on day 168 p.i. when no influenza virus gene was detected by RT-PCR, and (4) no apoptotic changes were detected despite the continuous existence of influenza virus genes.


CONCLUSIONS
In He/Le cells, telomerase activity was suppressed exclusively during the persistence of influenza, and no apoptotic changes were detected.
Hayase
Yukiharu
Y
Department of Virology, Jichi Medical School, Minamikawachi, Tochigi, Japan. yuhayase@jichi.ac.jp
Tobita
Kiyotake
K
D017209:Apoptosis; D006367:HeLa Cells / Q000821:virology; D006801:Humans; D009981:Influenza B virus / Q000472:pathogenicity*; D020133:Reverse Transcriptase Polymerase Chain Reaction; D019098:Telomerase / Q000235:genetics / Q000378:metabolism*
D019098:Telomerase