Washington, Jan 21 : Scientists have discovered a new type of treatment to stimulate the function of immune system and fight infection.

Our bodies are subject to attack by many different infectious particles (bacteria, viruses, etc.), which surround us in our everyday environment.

Various immune cells are activated to fight off these attacks: the first response is from the innate immune cells1, which gradually give way to the memory B and T lymphocytes of the adaptive immune system.

The Natural Killer (NK) cells are a part of this first line of defence of the organism. They can selectively kill tumour cells or cells infected by microbes whilst secreting chemical messengers known as cytokines, which stimulate and direct the response of the B and T lymphocytes.

Following the launch of a major genetics programme a few years ago, scientists succeeded in revealing a gene whose deactivation causes heightened functioning of the NK cells. This gene, called Ncr1, contributes to the manufacture of the receptor NKp46, which is present on the surface of NK cells. Surprisingly, its role in activating the NK cells has been known for several years.

"NK cells go through various stages of development before combating microorganisms or tumour cells," explained Sophie Ugolini, joint author of the study.

"Without this receptor, the NK cells are more reactive and therefore more effective when they encounter the attackers of the organism," she said.

To test the therapeutic potential of their discovery, the scientists blocked the NKp46 receptor using a drug (in this case, a monoclonal antibody). As in the genetics experiments, this treatment that blocks NKp46 makes the NK cells much more effective.

"Our aim now is to further explore the underlying biological mechanisms and to work in collaboration with the biopharmaceutical industry and the hospital to evaluate the medical potential of this new type of treatment, particularly for patients whose immune system has already been weakened, such as patients with an immunodeficiency and those who have had a bone marrow transplant or chemotherapy," concluded Eric Vivier.

Details of this work are published in the 20 January 2012 issue of the journal Science. (ANI)