Unraveling the mysteries of the natural killer within us

October 23, 2011

Scientists have discovered more about the intricacies of the immune system in a breakthrough that may help combat viral infections such as HIV.

Co-led by Professor Jamie Rossjohn of Monash University and Associate Professor Andrew Brooks from University of Melbourne, an international team of scientists have discovered more about the critical role Natural Killer cells play in the body's innate immune response.

The findings were published today in Nature.

Natural Killer cells are a unique type of white blood cell important in early immune responses to tumours and viruses. Unlike most cells of the immune system that are activated by molecules found on the pathogen or tumour, Natural Killer cells are shut down by a group of proteins found on healthy cells.

These de-activating proteins, known as Human Leukocyte Antigens or HLA molecules are absent in many tumours and cells infected with viruses, leaving them open to attack by the Natural Killer cells.

Natural Killer cells recognise the HLA molecules using an inbuilt surveillance system called "Killer cell immunoglobulin-like receptors" (KIR).

Using the Australian Synchrotron, the team determined the three dimensional shape of one of these key KIR proteins, termed KIR3DL1, which binds to a particular HLA molecule.

This pairing is known to play a role in limiting viral replication in people with HIV, slowing the progression of the disease to AIDS.

Professor Rossjohn said that better understanding the structure of KIR proteins may help to develop approaches to better utilise Natural Killer cells to combat viral infection.

"It is only possible to detect proteins, such as KIRs, using extremely high-end equipment. The use of the platform technologies at Monash and the Australian Synchrotron was absolutely essential to this project's success," Professor Rossjohn said.

Professor Brooks said the researchers would use these findings to investigate other KIR molecules.

"Since KIR3DL1 is only a single member of a much larger family of receptors, the study provides key insight into how Natural Killer cells utilise other members of this important family of receptors to recognise virus-infected cells and tumours." Professor Brooks said.
-end-
The five-year project involved international collaborations with researchers from the National Cancer Institute-Frederick, National Institute of Allergy and Infectious Diseases, National Institutes of Health and Cardiff University School of Medicine.

The research was funded by the National Health and Medical Research Council, the Australian Research Council, the Intramural Research Programs of the National Cancer Institute, the National Cancer Institute of Allergy and Infectious Diseases, Medical Research Council (UK) and National Institutes of Heath.

Monash University

Related Immune System Articles from Brightsurf:

How the immune system remembers viruses
For a person to acquire immunity to a disease, T cells must develop into memory cells after contact with the pathogen.

How does the immune system develop in the first days of life?
Researchers highlight the anti-inflammatory response taking place after birth and designed to shield the newborn from infection.

Memory training for the immune system
The immune system will memorize the pathogen after an infection and can therefore react promptly after reinfection with the same pathogen.

Immune system may have another job -- combatting depression
An inflammatory autoimmune response within the central nervous system similar to one linked to neurodegenerative diseases such as multiple sclerosis (MS) has also been found in the spinal fluid of healthy people, according to a new Yale-led study comparing immune system cells in the spinal fluid of MS patients and healthy subjects.

COVID-19: Immune system derails
Contrary to what has been generally assumed so far, a severe course of COVID-19 does not solely result in a strong immune reaction - rather, the immune response is caught in a continuous loop of activation and inhibition.

Immune cell steroids help tumours suppress the immune system, offering new drug targets
Tumours found to evade the immune system by telling immune cells to produce immunosuppressive steroids.

Immune system -- Knocked off balance
Instead of protecting us, the immune system can sometimes go awry, as in the case of autoimmune diseases and allergies.

Too much salt weakens the immune system
A high-salt diet is not only bad for one's blood pressure, but also for the immune system.

Parkinson's and the immune system
Mutations in the Parkin gene are a common cause of hereditary forms of Parkinson's disease.

How an immune system regulator shifts the balance of immune cells
Researchers have provided new insight on the role of cyclic AMP (cAMP) in regulating the immune response.

Read More: Immune System News and Immune System Current Events
Brightsurf.com is a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for sites to earn advertising fees by advertising and linking to Amazon.com.