Immunologists at The University of Texas at Austin have recorded visuals of T-cells learning what kind of cells to ignore when fighting pathogens, to ensure they do not attack healthy cells and tissues when fighting disease. It is the first time that this process has been captured on video.
For the first time ever, UT Austin researchers captured the process in which developing killer T-cells (purple and white) are tested by dendritic cells (yellow), and others, to see if they react to normal proteins from the body. This safety check insures that the T-cells don't harm normal cells in the body and cause autoimmune disorders.
T-cells are a type of white blood cell. They circulate the body searching for infections and other pathogens, and are essential to the human body.
T-cells are split into two distinct groups: killer T-cells, and helper T-cells. Killer T-cells are able to detect infected or cancerous cells by scanning the surface of the cell. Helper T-cells trigger immune responses. T-cells are able to recognize pathogens they encountered years ago, as well as naturally destroy cancerous cells and virally or bacterially infected cells.
An author of the study and an associate professor, Lauren Ehrlich explained the role T-cells carry out in the body.
T-cells have the daunting task of recognizing and fighting off all of the diverse pathogens that we encounter throughout our lives, while avoiding attacking our own healthy tissue. These cells mature in the thymus, an organ just above the heart, where they ‘get educated’ to not attack the body.”
Professor Lauren Ehrlich
The novel footage was captured by Ehrlich and postdoctoral researcher Jessica Lancaster, and was published in Nature Communications. To film the process, Ehrlich and Lancaster used two powerful lasers that fired in short pulses and scanned a portion of live tissue every 15 seconds.
A mouse model was used for the study, with the footage being captured in the thymus, a lymphoid organ found above the heart. This reconstructed the positions and movements of the cells, along with their intracellular signalling.
They were able to see that during a T-cells maturation process, other cells in the thymus help them to come into contact with a wide range of normal human proteins that they will need to ignore when fighting pathogens and triggering immune responses.
The researchers were able to gain more insight into how cells work collaboratively in the thymus and teach the maturing T-cells to self-destruct if they fail in carrying out their role correctly.
Ehrlich believes that this new imaging technique may lead the way to a better understanding of the processes that occur in the thymus. This deeper understanding may progress research in autoimmune disorders such as Type 1 diabetes, along with the risks of autoimmune disorders in people who have undergone bone marrow transplants. T-cells are often overactive in these situations, and can attack healthy cells by accident. This new imaging technique is not only a scientific first, but an important step into understanding autoimmune disorders.
Sources
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