About My Health Careers Internship MedBlogs Contact us
Medindia LOGIN REGISTER
Advertisement

Fresh Insights into Tuberculosis

by Colleen Fleiss on May 15, 2018 at 2:03 AM
Font : A-A+

Fresh Insights into Tuberculosis

Researchers have found that rather than fighting to resist the pathogen, the body's tolerance to Mycobacterium tuberculosis, or Mtb is the key mechanism for preventing the spread of the infection. More surprisingly, they found that having excessive levels of T cells, which are known as soldiers of our immune system, could cause more harm than good.

Advertisement


Since the discovery of Mycobacterium tuberculosis, or Mtb, (the bacteria causing TB) over a century ago, great progress has been made in defining strategies that facilitate elimination of the bacteria. For instance, the discovery of antibiotics was a major breakthrough in the treatment of active TB. However, greater than 90 per cent of TB-infected individuals tolerate the bacteria without any treatment. Dr. Maziar Divangahi, a pulmonary immunologist at the Research Institute of the McGill University Health Centre (RI-MUHC) and a professor of Medicine at McGill University in Montreal, has been try-ing to explain why the vast majority of people infected with Mtb can tolerate the infection without developing disease. Clinicians refer to this condition as "latent tuberculosis", and it affects a quarter of the global population. "TB is a perfect example of disease tolerance," says Dr. Divangahi who is also the associate director of the Translational Research in Respiratory Diseases Program at the RI-MUHC and a member of the McGill International TB Centre.

"We always thought that having more T cells would provide better protection against TB. Instead, we found that it could imbalance disease tolerance causing extensive tissue damage and ultimately killing the host," says Dr. Divangahi, lead author of the study published today in Science Immunology, who is the also the associate director of the Meakins-Christie Laboratories.
Advertisement

Disease tolerance versus host resistance

Our body's defense system is divided into two arms: one is resistance, which aims to eliminate the pathogen, while the other is tolerance, which is designed to control the tissue damage caused by the infection. "While disease tolerance is an established field of research in simple organisms such as plants, our un-derstanding of this host defense strategy in humans is very limited," says Dr. Divangahi.

Although, immunologists and vaccinologists have made progress in the study of host resistance to infectious diseases, little is known about the mechanisms of disease tolerance in humans.

A key protein in disease tolerance

Dr. Divangahi's team determined that a protein in the mitochondria called cyclophilin D (CypD) acts as a key checkpoint for T cell activation. Through collaboration with Dr. Russell Jones from McGill University, who is an international expert in T cell biology, they identified that CypD is required for controlling T cell metabolism. "T cells are traditionally considered to be important in eliminating Mtb," says Dr. Divangahi. "However, we found that increasing T cell activation in mice by eliminating a metabolic checkpoint unexpectedly compromised host survival without any impact on the growth of Mtb." "In contrast to conventional thinking, we show that T cells are essential for regulating the body's toler-ance to Mtb infection," explains one of the study's first authors, Dr. Nargis Khan, who is currently a postdoctoral fellow in Dr. Divangahi's lab at the RI-MUHC.

Giving the widespread drug resistance to various Mtb strains the limited pipeline of effective antibiotics and the lack of an efficient vaccine, alternative approaches to treat TB are urgent. "If we could understand the mechanisms of 'natural immunity' that controls TB in 90-95 per cent of infected individuals," says Dr. Divangahi,"we will able to design a novel therapy or vaccine to substantially reduce the world wide burden of this ancient disease."

Source: Eurekalert
Advertisement

Advertisement
News A-Z
A B C D E F G H I J K L M N O P Q R S T U V W X Y Z
Advertisement
News Category
What's New on Medindia
International Day of Persons with Disabilities 2021 - Fighting for Rights in the Post-COVID Era
Effect of Blood Group Type on COVID-19 Risk and Severity
Woman with Rare Spinal Cord Defect from Birth Sues Doctor
View all

Medindia Newsletters Subscribe to our Free Newsletters!
Terms & Conditions and Privacy Policy.

More News on:
Tuberculosis Tracheostomy Pleural Effusion Silicosis Screening Tests for Tuberculosis Fever Cough Symptom Evaluation Diet in Tuberculosis Stomach Tuberculosis Extra Pulmonary Tuberculosis 

Recommended Reading
Screening Tests for Tuberculosis
Tuberculin skin test and Interferon - Release Assays are tests used to screen for tuberculosis....
Diet in Tuberculosis
Patients with tuberculosis should eat a healthy diet so that they build up their immunity to fight ....
Quiz on Tuberculosis
Tuberculosis is a major health care concern, especially in Africa and South East Asia. Brush up ......
The Lungs - Animation
The lungs are our organs of respiration. It is within these, that exchange of gases takes place....
Cough Symptom Evaluation
Cough is a symptom of a condition usually affecting the respiratory tract. It may be acute or chroni...
Extra Pulmonary Tuberculosis
Extra pulmonary tuberculosis is infection of tissues and organs other than the lungs by mycobacteriu...
Fever
Fever or Pyrexia is an elevation in normal body temperature. Causes of fever include infections, inj...
Pleural Effusion
Pleural effusion is the accumulation of fluid in the space between the two coverings (pleura) of the...
Silicosis
Silicosis is a lung disease caused by inhalation of crystalline free silica dust. It is characterise...
Stomach Tuberculosis
Abdominal tuberculosis, which is a form of extrapulmonary tuberculosis, affects the gastrointestinal...
Tuberculosis
Tuberculosis, caused by Mycobacterium tuberculosis, primarily affects the lung. It may spread to oth...

Disclaimer - All information and content on this site are for information and educational purposes only. The information should not be used for either diagnosis or treatment or both for any health related problem or disease. Always seek the advice of a qualified physician for medical diagnosis and treatment. Full Disclaimer

© All Rights Reserved 1997 - 2021

This site uses cookies to deliver our services. By using our site, you acknowledge that you have read and understand our Cookie Policy, Privacy Policy, and our Terms of Use