JUN 17, 2016 10:00 AM PDT

Immune Cells Declare War On Legionnaires' Disease

WRITTEN BY: Kara Marker
The summer of 2015 in the South Bronx, New York City saw the worst outbreak of Legionnaires’ disease the city had ever seen: 12 died and more than 120 fell ill. Legionnaires’ is a respiratory disease caused by a bacterial species called Legionella pneumophila. As the numbers of Legionnaires’ outbreaks are on the rise since its initial discovery in 1976, scientists are eager to find a more effective way to kill these bacteria. In a new study from the University of Melbourne, researchers identified a new cell type that could be the key to achieving this goal.
 Image credit - University of Melbourne
L. pneumophila invades sources of water like lakes, streams, and human-made water systems. Once someone breathes in water droplets via mist from a contaminated source, the bacteria are free to multiply in their lungs. Although most healthy immune systems can prevent an infection after exposure to L. pneumophila, people at risk include older people, smokers, those with chronic lung diseases, and the immunocompromised. The new study from Melbourne looks at how a healthy person fights off Legionnaires’ disease in hopes that scientists can develop a new treatment based on the body’s natural method of preventing or clearing an infection.
 
Melbourne PhD student Andrew Brown was the one to discover a population of monocyte-derived cells (MCs) doing most of the dirty work in Legionnaires’-ridden lungs. Rather than the macrophages, the MCs were seen engulfing and breaking down bacterial cells within 24 hours of a Legionnaires’ infection. After 48 hours, there were ten times as many MCs as macrophages going to town on the bacteria.
 
“Knowing this, we can now focus on how to manipulate and optimize the immune response to fight infection,” said lead researcher Elizabeth Harland, PhD.
 
MCs are first-responders of the innate immune system, secreting interleukin-12 as a signal for T lymphocytes to get involved in the attack. T lymphocytes then secrete interferon gamma, a chemical messenger that responds to the call and prompts the MCs to go ahead with annihilating the L. pneumophila population.
 
The Melbourne researchers were surprised to find the population of MCs taking lead on the destruction of the infection, but they are glad they found what they did. Understanding more completely how the immune system deals with a Legionnaires’ infection well help them provide better prognoses to sick patients, and this study of Legionnaires’ could potentially help them understand the immune response to other acute lung infections.
 
Lastly, the researchers believe that they will be able to take this information and use it to understand the status of a person’s immune attack in a given case of Legionnaires’ disease. Is the immune system on top of things or does the patient need reinforcements sent in? With the reinforcements being appropriate levels of antibiotics, researchers now have a better method of regulating how often these drugs are being used.
 

 
Sources: University of Melbourne, Centers for Disease Control and Prevention, Wall Street Journal
About the Author
  • I am a scientific journalist and enthusiast, especially in the realm of biomedicine. I am passionate about conveying the truth in scientific phenomena and subsequently improving health and public awareness. Sometimes scientific research needs a translator to effectively communicate the scientific jargon present in significant findings. I plan to be that translating communicator, and I hope to decrease the spread of misrepresented scientific phenomena! Check out my science blog: ScienceKara.com.
You May Also Like
JUL 22, 2019
Immunology
JUL 22, 2019
How to Kill Superbugs
https://www.technologynetworks.com/immunology/news/enhancing-the-infection-fighting-potential-of-natural-products-321553...
AUG 04, 2019
Immunology
AUG 04, 2019
New Research In Reversing Deafness
Hair cells inside the human ear are responsible for sensing and relaying sound to the brain.  In all mammals except humans, these cells can regenerate...
NOV 03, 2019
Genetics & Genomics
NOV 03, 2019
Can CRISPR Replace Antibiotics?
Antibiotic-resistant infections claim around 700,000 lives per year, with estimates saying that this number could swell to 10 million by 2050 (Jacobs: 2019...
NOV 12, 2019
Immunology
NOV 12, 2019
Allergy Shots May Work for Kids with Pollen Food Allergy Syndrome
It’s not common for young children to develop pollen food allergy syndrome (PFAS), but for those that do, there’s not too much parents can do o...
DEC 05, 2019
Drug Discovery & Development
DEC 05, 2019
New Injection that Treats Peanut Allergy
Peanut allergies affect between 1 and 3% of the US population. Associated with a heightened risk of severe anaphylactic reactions, oral immunotherapy is th...
FEB 19, 2020
Immunology
FEB 19, 2020
Rainbow trout hold the key to unravelling immunological mysteries
What do the gut microbiome, antibodies, and rainbow trout have in common? A lot, says researcher J. Oriol Sunyer from the University of Pennsylvania’...
Loading Comments...