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Bystander virus infection prolongs activated T cell survival
T Mitchell1, J Kappler, P Marrack
1Department of Medicine, National Jewish Medical and Research Center, Howard Hughes Medical Institute, Denver, CO 80206, USA.
Journal of Immunology (Baltimore, Md. : 1950)
|April 14, 1999
Summary
Viral infections enhance T cell survival after activation, a phenomenon independent of known survival factors. This suggests novel mechanisms by which viruses influence immune responses and potentially trigger autoimmunity.
Area of Science:
- Immunology
- Virology
- Cell Biology
Background:
- T cells (T lymphocytes) typically undergo rapid apoptosis after activation unless inflammatory signals are present.
- Understanding T cell survival mechanisms is crucial for comprehending effective immune responses.
Purpose of the Study:
- To investigate how viral infections influence the survival of activated T cells.
- To elucidate the mechanisms underlying the bystander effect of viral infection on T cell fate.
Main Methods:
- Studied T cells responding to a superantigen in the context of vaccinia virus infection in mice.
- Assessed T cell survival in vivo and in cell culture.
- Evaluated factors including initial T cell response magnitude, Bcl-2 and Bcl-x induction, proliferation, and Fas-mediated killing.
Main Results:
- T cells activated during vaccinia infection exhibited prolonged survival compared to those activated in uninfected mice.
- This enhanced survival (bystander effect) was not linked to changes in initial T cell response magnitude, Bcl-2/Bcl-x expression, proliferation, or Fas-mediated apoptosis.
- Known mechanisms of T cell survival did not fully explain the observed phenomenon.
Conclusions:
- Viral infections employ novel mechanisms to promote the survival of activated T cells.
- These virus-induced survival pathways may differ from previously understood T cell regulation.
- The findings suggest a potential link between these mechanisms and the induction of virus-associated autoimmunity.