A step forward in the fight against bacterial infections

February 01, 2006

Bacterial infections can strike anyone, and they can sometimes be fatal. Because more and more bacteria are becoming resistant to the pre-eminent remedy; antibiotics; the search for new remedies against bacterial infections is in high gear. Research by scientists from the Flanders Interuniversity Institute for Biotechnology (VIB) connected to Ghent University shows that certain mice, by nature, can withstand particular bacterial infections. Elucidation of the biological process that underlies this natural ability offers perspectives for the development of new therapeutics.

A cascade of reactions protects us against infections

Most of the time, our body can overcome bacterial infections. Only a limited number of bacteria can make us sick, but sometimes they can be fatal. In the US, about 200,000 people die from bacterial infections each year. Normally, our natural immune system bars bacteria from entering our body, or it renders them harmless. The aggressiveness of the bacteria, our general state of health, and the speed with which our immune system reacts determine whether or not we become sick after contact with a bacterium.

Upon contact with a bacterium, or a bacterial component, the immune system springs into action. One such component of the bacterial cell wall is LPS. The binding of LPS with its specific receptor in our immune system − TLR4 − initiates a long series of reactions that bring on an inflammation, which eliminates the bacteria from our body. Of course, this chain of reactions is strictly controlled, because excessive inflammation can lead to lethal shock.

Mice that are able to cope with acute inflammations

Tina Mahieu and her colleagues from the research group led by Claude Libert are working with mice that are not susceptible to toxic LPS. The VIB researchers have discovered the mechanism behind this insensitivity.

One of the steps in the process of inflammation following contact with LPS is a profuse production of type 1 interferons. These proteins play an important role in the regulation of immunity. The Ghent researchers administered 10 times the lethal dose of LPS to the mutant mice, without deadly consequences. This finding could not be attributed to an alteration in TLR4, but to a reduced production of type 1 interferons. To verify this, Mahieu and her colleagues administered these interferons preventatively to the mice − which made the animals susceptible to LPS once again. Thus, this research shows that the mice are no longer able to produce large quantities of type 1 interferons − with the consequence that an inflammation fails to arise, demonstrating the importance of type 1 interferons to the inflammation process. On the other hand, the mice produce just enough interferons to activate the immune system against the bacteria, so that the mice are protected against bacterial infections.

Another step forward in the battle against bacterial infections

The results of this research are very relevant to the quest for new therapeutics for bacterial infections. The mutant mice display a combination of important characteristics: they are resistant to LPS, but they still recognize and destroy pathogens. The limited quantity of type 1 interferons enables the mice to cope with a lethal shock resulting from inflammation, but this small quantity also ensures that immunity is preserved. A next step in combating bacterial infections is to uncover the mechanism behind this reduced production.
-end-


VIB (the Flanders Institute for Biotechnology)

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.