Infected cells kill themselves to halt virus

Sydney, Jan 16 (IANS) Infected mammalian cells kill themselves to prevent infection and ensure the greater good of its numbers.

By killing itself, the cell can ensure that the virus does not spread throughout the body. Cellular responses to a virus can include production of anti-viral proteins, but also suicide of the infected cell.

'It has recently become apparent that the detection of the genetic material of the virus is a major route through which cells respond to infection,' said Kate Stacey of the Institute for Molecular Bioscience, Queensland University.

The mammalian cell is able to recognise foreign DNA because its own is housed within its nucleus. The presence of DNA outside the nucleus is a sure sign that something is wrong, and may indicate the presence of a viral invader.

Stacey and fellow scientists Tara Roberts, David Hume and doctoral student Adi Idris discovered two proteins in mouse cells, one of which induces cell suicide in response to foreign DNA, and one that prevents it.

'AIM2 triggers cell suicide when it senses DNA outside the nucleus,' Stacey said. Conversely, 'a closely-related protein called p202 binds foreign DNA and prevents cell death', according to a university release.

The discovery has a range of implications. It will improve understanding of how cells normally combat viral infection, and may also be relevant for the disease lupus, where the immune system attacks normal cellular proteins.

The research was published in Science.