Tuberculosis, which kills over 2 million people each year, is caused primarily by infectious bacteria known as Mycobacterium tuberculosis – or Mtb. Mtb targets human immune cells as part of its strategy to avoid detection, effectively neutralizing the body's immune response.
Up until now, scientists had a general understanding of the process, but researchers in the Immunity and Infection Research Centre at Vancouver Coastal Health Research Institute and the University of British Columbia have shown Mtb produces a specific protein that allows it to defuse and bypass the body's security system. The results are published today in The Proceedings of the National Academy of Sciences, and provide a pathway for improved treatments against this disease.
"TB has been able to completely mislead our immune systems, convincing our body it isn't there, which is why it is such an effective killer," says Dr. Yossef Av-Gay, research scientist with the Immunity and Infection Research Centre at the Vancouver Coastal Research Institute and professor in the Division of Infectious Disease at UBC Faculty of Medicine. "We discovered that the cells in charge of targeting and destroying invading bacteria are being fooled by a special protein that blocks the immune cells ability to recognize and destroy it."
Here is how it works. Macrophages are dedicated human immune cells with the role of identifying and defeating dangerous microorganisms. Normally, macrophages engulf bacteria, or other infectious agents, and contain them in an enclosed secluded environment. Then, special components of the cell (cellular organelles) move to the controlled area and release acid enzymes that dissolve the bacteria. The system works beautifully against most infectious agents. However, as Dr. Av-Gay's team found, Mtb operates in a stealth manner, turning off this immune response.
In the case of Mtb, once the bacteria become engulfed by macrophages, they secrete a protein named PtpA that disables the two separate mechanisms required for making the acidic environment that normally targets them. The end result is that Mtb lives comfortably in the immune cells, like a Trojan horse, hidden from the rest of the immune system. The bacteria then multiply inside the macrophage, and when released, they attack the body.
"We have been engaged in studying the interaction between the TB bacterium and the human macrophage over the past decade," says Dr. Av-Gay. "We are delighted with this discovery. Through learning about the tricks it uses, we now have new targets, so that we can develop better drugs against this devastating disease."
TB is the leading cause of death among infectious diseases in the world today and is responsible for one in four adult preventable deaths, according to the World Health Organization (WHO). Every 20 seconds TB kills someone, with approximately 4400 people dying every day. The WHO estimates that one-third of the world's population is infected.
Vancouver Coastal Health Research Institute is the research body of Vancouver Coastal Health Authority, which includes BC's largest academic and teaching health sciences centres: Vancouver General Hospital, UBC Hospital, and GF Strong Rehabilitation Centre. The institute is academically affiliated with UBC Faculty of Medicine, and is one of Canada's top funded research centres, with $82.4 million in research funding for 2009/2010. www.vchri.ca.
The University of British Columbia (UBC) is one of North America's largest public research and teaching institutions, and one of only two Canadian institutions consistently ranked among the world's 40 best universities. Surrounded by the beauty of the Canadian West, it is a place that inspires bold, new ways of thinking that have helped make it a national leader in areas as diverse as community service learning, sustainability and research commercialization. UBC offers more than 55,000 students a range of innovative programs and attracts $550 million per year in research funding from government, non-profit organizations and industry through 7,000 grants.For media enquiries, please contact: Lisa Carver, Communications & Public Affairs
VCH/VCH Research Institute - 604 875-4111 x 61777 or 604 319-7533 – firstname.lastname@example.org
Lisa Carver | EurekAlert!
Structural framework for tumors also provides immune protection
26.02.2020 | Medical College of Georgia at Augusta University
Finding new clues to brain cancer treatment
21.02.2020 | Case Western Reserve University
Researchers at the University of Bayreuth have discovered an unusual material: When cooled down to two degrees Celsius, its crystal structure and electronic properties change abruptly and significantly. In this new state, the distances between iron atoms can be tailored with the help of light beams. This opens up intriguing possibilities for application in the field of information technology. The scientists have presented their discovery in the journal "Angewandte Chemie - International Edition". The new findings are the result of close cooperation with partnering facilities in Augsburg, Dresden, Hamburg, and Moscow.
The material is an unusual form of iron oxide with the formula Fe₅O₆. The researchers produced it at a pressure of 15 gigapascals in a high-pressure laboratory...
Study by Mainz physicists indicates that the next generation of neutrino experiments may well find the answer to one of the most pressing issues in neutrino physics
Among the most exciting challenges in modern physics is the identification of the neutrino mass ordering. Physicists from the Cluster of Excellence PRISMA+ at...
Fraunhofer researchers are investigating the potential of microimplants to stimulate nerve cells and treat chronic conditions like asthma, diabetes, or Parkinson’s disease. Find out what makes this form of treatment so appealing and which challenges the researchers still have to master.
A study by the Robert Koch Institute has found that one in four women will suffer from weak bladders at some point in their lives. Treatments of this condition...
The operational speed of semiconductors in various electronic and optoelectronic devices is limited to several gigahertz (a billion oscillations per second). This constrains the upper limit of the operational speed of computing. Now researchers from the Max Planck Institute for the Structure and Dynamics of Matter in Hamburg, Germany, and the Indian Institute of Technology in Bombay have explained how these processes can be sped up through the use of light waves and defected solid materials.
Light waves perform several hundred trillion oscillations per second. Hence, it is natural to envision employing light oscillations to drive the electronic...
Most natural and artificial surfaces are rough: metals and even glasses that appear smooth to the naked eye can look like jagged mountain ranges under the microscope. There is currently no uniform theory about the origin of this roughness despite it being observed on all scales, from the atomic to the tectonic. Scientists suspect that the rough surface is formed by irreversible plastic deformation that occurs in many processes of mechanical machining of components such as milling.
Prof. Dr. Lars Pastewka from the Simulation group at the Department of Microsystems Engineering at the University of Freiburg and his team have simulated such...
12.02.2020 | Event News
16.01.2020 | Event News
15.01.2020 | Event News
26.02.2020 | Information Technology
26.02.2020 | Life Sciences
26.02.2020 | Health and Medicine