The invasion of foreign bodies into the body is identified and neutralized by the action of antibodies (also known as immunoglobulins) which are a class of Y-shaped proteins made by the white blood cells, that help the immune system combat infections and keep the body fit.
Antibodies
When a foreign body like a virus, enters the human body, lymphocytes – important white blood cells that initiate the defense mechanism of the immune system – recognizes it by a special protein present on its surface (antigen) and produces the Y-shaped foreign-invaders hunters that bind to it, neutralizing its harmful effect.
How do antibodies do this?
To discover how antibodies attach to their target, a team of researchers from KTH Royal Institute of Technology and Karolinska Institute built a model that revealed that the movement of these antibodies towards the foreign invader may be likened to that of a child walking on stones laid in a brook.
Although from past studies, antibodies have been known to be Y-shaped protein molecules, they are more likely shaped in the opposite direction, that is, with the two branches down and the tail up – similar to a stick human (as reported by recent studies). The team discovered that the antibodies attach to the invaders by sticking their look-alike feet to the antigens found on the outer bodies of the pathogens; they attach to two different antigens, allowing them to establish a firmer hold of the invaders. Once this is achieved, they (antibodies) undergo some series of reactions involving other proteins, to deactivate the pathogen.
However, this discovery raised some questions in the minds of the researchers, as regards the possible positions of these antigens to the assumed feet of the antibodies: they wanted to know how the antibodies would be attached to antigens that are widely spaced and closely positioned.
The answer they sought
They created a similar pathogen-antigen existence employing the DNA origami technique – a technique where DNA folds itself into smaller molecules having the dimension of a nanometer – which made them able to vary the distance between the antigens. They were able to collect data from this procedure to aid the research.
Next, they inputted the data they collected into a model built using nanotechnology; this model provided them the answers they sought, revealing that the antibodies behave like any other bipedal organism, particularly humans: if the antigens are widely apart, the antibodies are capable of moving to a suitable position where they can be able to bind effectively to both antigens.
They are currently working to improve this discovery to be able to replicate this behavior of antibodies in the biological environment.
Clinical significance
Identifying the movement of antibodies to the position of antigens at any given time is important to aid improvement in vaccines production.
Conclusion
Scientists have been able to discover the actual movement of antibodies with regards to the varying separation distance of the antigens on the outer bodies of the invaders.
Reference
Stochastic modeling of antibody binding predicts programmable migration on antigen patterns
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