Key Structure of Complement System Revealed by Research Team

A research team from the University of Leicester, in the United Kingdom, has managed to map the entire structure of a key component from the human immune system – specifically, the C1 complement component. This is responsible for the neutralization of viruses and bacteria.

The C1 complement complex is actually a protein that is responsible for the detection of foreign molecules in the blood. These molecules, depending on their nature, can cause different diseases. If so, they are called pathogens. If these pathogens are bacteria, fungi, viruses or other types of pathogens, the complement system is activated. The complement system further activates the immune system by activating MAC (membrane attack complex) proteins, responsible for attacking and neutralizing the foreign molecules.

Even though the C1 complement complex was first discovered approximately 50 years ago, the process through which it aids the immune system has been incompletely elucidated until now. The current study began almost 3 years ago, and was founded by the Medical Research Council and the Wellcome Trust. The research team from Leicester worked in close collaboration with researchers from the Warwick Medical School of the University of California, from the United States, and with the Hungarian Academy of Sciences in Budapest, Hungary.

Researchers suggest that their discovery is extremely important and brings important insight towards a better understanding of the human immune system. Furthermore, such a discovery could lead to the development of specific medication that would prevent the complement system from going awry. For example, if a patient suffers from either a heart attack, or a stroke, the complement system begins to target the patient’s own tissue, thus preventing the organism from recovering faster.

The understanding of the structural build of the C1 complement complex will help researchers develop inhibitory drugs in order to stop the complement system from working against its own organism. In their study, the research team revealed the pathway through which the C1 complement complex is formed. There are 3 constituents that form the final product – the C1q (responsible for the actual recognition of the foreign molecules), and C1r & C1s (responsible for the further activation of the complement cascade).

The lead author of the study, Dr Russel Wallis, notes that they have managed, for the first time in history, to determine the whole structure of the C1 complement complex. Furthermore, the study brings new information on the pathway that activates the complement cascade. Wallis further explains that they were able to investigate the whole structure of the complex through a series of overlapping segments. According to the results, the C1 complement complex looks like a bouquet of flowers, with the C1q, C1r, and C1s proteins being linked together.

The study will aid future studies towards a better understanding of the complex pathways used bu the immune system in order to prevent various diseases. Moreover, it’s a possible stepping stone for later studies regarding the development of better drugs against the bad activation of the complement cascade in circumstances such as a heart attack, a stroke, or even an HIV/AIDS infection.