Scientists map structure of key complex in the immune system

November 4, 2013

Leicester scientists have mapped the "bouquet-like" structure of a key part of the body's immune system responsible for neutralising bacteria and viruses.

A team from the University of Leicester's Departments of Infection, Immunity, and Inflammation and Biochemistry led a project which has mapped the structure of complement component C1 - a large complex of the .

The C1 complex is a which is responsible for spotting foreign agents in the blood which can cause disease - known as pathogens.

When it comes across bacteria, viruses, fungi and other objects, it sets off a process called the complement system.

This stimulates the body's immune system including the activation of membrane attack complex (MAC) proteins which attack and kill the foreign cells.

Although the C1 complex was first identified more than 50 years ago, the way it works has been poorly understood until now.

The three-year project was funded by the Medical Research Council and the Wellcome Trust.

Working with colleagues at Warwick Medical School, the University of California, San Diego, and the Hungarian Academy of Sciences, Budapest, the Leicester researchers have revealed the constituent parts which make up the C1 complex.

This is extremely useful for helping us understand our own immune system - and could help us develop treatments to prevent the complement system from going wrong.

In some instances - including following a or stroke - the complement system attacks our own tissues, preventing the body from recovering.

Understanding the structure of the C1 complex could help scientists develop inhibitors to prevent the complement system from working against us in these cases.

The research reveals how the C1 complex is formed from constituent parts called C1q - the subcomponent responsible for recognising targets - and C1r and C1s, which activate further developments in the complement process.

Dr Russell Wallis, of the University of Leicester's Departments of Infection, Immunity and Inflammation and Biochemistry, who led the project, said: "We have determined the structure of part of a large complex (called complement component C1) of the immune system. It recognises pathogens and neutralises them by triggering a reaction pathway called complement.

"Our study reveals for the first time how the complex is assembled from its constituent proteins and suggests how it activates the complement cascade.

"We were able to piece together the of the full-size complex from the structures of a series of overlapping segments. It looks like a bouquet of flowers. Our study has shown how the C1q, C1r and C1s proteins fit together.

"This finding helps us to understand how the immune system prevents disease and over the longer term may facilitate the development of new therapeutics.

"For example, the complement system attacks our own tissues in a number of disease states such as following a heart attack or stroke. Under these circumstances, use of inhibitors of complement could prevent this damage from occurring and allow the to recover."

Explore further: Chain reaction in the human immune system trapped in crystals

More information: The paper can be found at:

Related Stories

Researchers discover immune pathway

November 6, 2012

Researchers from Aarhus University, Denmark, have now discovered an important mechanism behind one of our most fundamental lines of immune function. The discovery has been published in the esteemed scientific journal, The ...

Discovery shows fat triggers rheumatoid arthritis

May 8, 2013

Scientists have discovered that fat cells in the knee secrete a protein linked to arthritis, a finding that paves the way for new gene therapies that could offer relief and mobility to millions worldwide.

Rare gene variant linked to macular degeneration

September 17, 2013

An international team of researchers, led by scientists at The Genome Institute at Washington University School of Medicine in St. Louis and the University of Michigan School of Public Health in Ann Arbor, has identified ...

Recommended for you

Snapshot turns T cell immunology on its head

October 6, 2015

Challenging a universally accepted, longstanding consensus in the field of immunity requires hard evidence. New research from the Australian Research Council Centre of excellence in advanced Molecular imaging has shown the ...

Four gut bacteria decrease asthma risk in infants

September 30, 2015

New research by scientists at UBC and BC Children's Hospital finds that infants can be protected from getting asthma if they acquire four types of gut bacteria by three months of age. More than 300 families from across Canada ...

Flu infection reveals many paths to immune response

September 28, 2015

A new study of influenza infection in an animal model broadens understanding of how the immune system responds to flu virus, showing that the process is more dynamic than usually described, engaging a broader array of biological ...

Immune cells may help fight against obesity

September 15, 2015

While a healthy lifestyle and "good genes" are known to help prevent obesity, new research published on September 15 in Immunity indicates that certain aspects of the immune system may also play an important role. In the ...

1 comment

Adjust slider to filter visible comments by rank

Display comments: newest first

1 / 5 (4) Nov 04, 2013

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.