Washington, Oct 2 :Natural killer (NK) cells, part of our immune system, kill cells infected with a given virus. Researchers have now found that the cells also help keep T-cells from over-responding.

Such a balance helps T-cells -- that also kill the body's own cells after being infected by viruses or bacteria -- maintain their role in the body's adaptive immune response, rather than becoming too numerous and activated to cause harm.

The discovery by researchers from Brown University (US) and McGill University (Canada could someday be used to help treat patients with compromised immune systems. Managing NK cell production might help stabilise the immune systems of people with HIV or keep patients from rejecting bone marrow or organ transplants.

The findings place an importance on understanding how to keep NK cells around, because they can be lost, said lead author Christine Biron, professor of medical science at Brown University.

Scientists have known that NK cells have antimicrobial effects. But the newer research focuses on factors that help keep NK cells around, said a release of Brown University.

These findings were published in the September issue of The Journal of Experimental Medicine.(IANS)