AUG 29, 2017 03:46 PM PDT

Understanding How Tuberculosis Takes Hold

WRITTEN BY: Carmen Leitch

New work by researchers at the University of Cambridge has provided insight into how tuberculosis infections get a foothold and begin to grow. Mycobacterium tuberculosis is the bacterium that causes the illness, which is a leading cause of death worldwide but impacts fewer than 200,000 people annually in the United States. According to the World Health Organization, while 95 percent of tuberculosis deaths happen in low-income countries, infections that are resistant to treatment are on the rise. Learning more about the disease is vital if we are to control outbreaks.

The new research, published in the journal Cell, may help to prevent tuberculosis infections by helping scientists develop better treatments or vaccines. The video is the abstract for this work, by the authors.

The Mycobacterium tuberculosis (Mtb) bacterium enters the lung, where it encounters macrophages that reside there. These macrophages are important immune cells are part of our first line of defense against invaders. They work to remove particles and microbes from the air we breathe.

A zebrafish model demonstrated that the pathogenic Mtb gets taken up by these lung-resident macrophages, and then destroyed. That suggested that for an infection to be established, the bacterium has to escape the resident macrophages, and into monocytes. The monocytes will allow growth of the bacterium, which is then able to get an infection going.

Scanning electron micrograph of Mycobacterium tuberculosis bacteria, which cause TB. / Credit: NIAID

This was also the case for another pathogen that the researchers analyzed, Mycobacterium leprae, the bacterium that causes leprosy.

"These 'Pac-Man'-like immune cells swallow the leprosy bacteria, but are not always able to destroy them," explained senior author of the new report, Lalita Ramakrishnan, a Professor at the Department of Medicine at the University of Cambridge. Ramakrishnan’s lab is part of the Medical Research Council's Laboratory of Molecular Biology. In the case of leprosy, the bacterium impacts nerves. "Instead [of destroying the bacteria], the macrophages -- which should be moving up and down the nerve fiber repairing damage -- slow down and settle in place, destroying the myelin sheath."

In tuberculosis, Mtb is helped along by a molecule called mycobacterial membrane phenolic glycolipid (PGL), which is crucial to enabling the transition from macrophage to monocyte. PGL activates a pathway which eventually leads to the recruitment of monocytes for the establishment of an infection. The investigators believe that PGL now presents a therapeutic target.

 

 

 

Sources: Cell, Science Daily, World Health Organization

About the Author
  • Experienced research scientist and technical expert with authorships on 28 peer-reviewed publications, traveler to over 60 countries, published photographer and internationally-exhibited painter, volunteer trained in disaster-response, CPR and DV counseling.
You May Also Like
SEP 22, 2018
Videos
SEP 22, 2018
Did a Vampire Facial Expose Patients to Bloodborne Disease?
It seems there is no shortage of unusual beauty rituals; vampire facials may fall into that category....
OCT 11, 2018
Microbiology
OCT 11, 2018
New Vaccine Protects Against Lassa Fever and Rabies
In Africa, Lassa fever is a significant threat to public health. It is a member of the same family of viruses as Ebola....
OCT 16, 2018
Videos
OCT 16, 2018
Can the Bacteria That we Carry Give us Special Powers?
The bacteria that we carry in and on our bodies can affect our health and well-being in many ways....
NOV 15, 2018
Videos
NOV 15, 2018
A Season of Outbreaks
In a few different places around the world, people are facing disease outbreaks due to pathogenic microbes....
NOV 21, 2018
Videos
NOV 21, 2018
The CDC Issues a Serious Warning About All Romaine Lettuce
Don't eat any romaine lettuce, and throw away any you may have at home....
NOV 30, 2018
Microbiology
NOV 30, 2018
C-Section Deliveries Disrupt the Transmission of Microbes From Mom to Baby
From our earliest days, bacteria exert a powerful influence on many aspects of our health....
Loading Comments...