Research by UC Irvine immunologists reveals new information about how our immune system functions, shedding light on a vital process that determines how the body’s ability to fight infection develops.
In the online version of Nature Immunology, neurology professor Dr. Michael Demetriou, postdoctoral scholar Raymond Zhou and other Institute for Immunology colleagues describe a critical mechanism underlying how T cells are created, selected and released into the bloodstream.
A T cell is a type of blood cell called a lymphocyte that protects the body from infection. T cell precursors called thymocytes are created in the bone marrow and migrate to the thymus – a walnut-sized organ at the base of the neck – where they turn into T cells.
However, very few thymocytes become fully functional T cells, and in the current study, the Demetriou team gained important new insights into why.
As they transform into T cells, thymocytes grow receptors that react to an antigen (any substance provoking an immune response) that’s bound to a small molecule called MHC. If this reaction is too strong or too weak, the thymocyte does not mature into a T cell.
Demetriou and the others found that the delicate balance determining the proper reactive ability is controlled by glycosylation, a process in which a sugar attaches to a target protein to give the protein stability and form. They saw that changes in the addition of sugars to receptors – including the blocking of glycosylation – during T cell development profoundly influenced how thymocytes reacted to the MHC-bound antigens and whether they became mature T cells.
Glycosylation also may help explain the creation of self-reactive T cells that escape from the thymus and can go on to attack the body’s own antigens, a process called autoimmunity that’s the basis of immune system disorders such as multiple sclerosis.
“Understanding how T cells are selected for antigen reactivity has been an enigma, and here we have made a major advance in understanding how this selection works,” Demetriou says.
The work, he added, represents a breakthrough in basic research and facilitates further discoveries about T cell processes that could someday yield new therapeutic approaches to infection and autoimmune diseases.
Haik Mkhikian, Ani Grigorian, Amanda Hong, David Chen and Araz Arakelyan of UCI contributed to the study, which received support from the National Institute of Allergy & Infectious Diseases (grant R01 AI053331) and the National Heart, Lung & Blood Institute (grant F30HL108451).
University of California, Irvine:
A Helping Hand: Innovative Approaches to Expanding Hand Hygiene Programs in Acute Care Settings
July 9th 2025Who knew candy, UV lights, and a college kid in scrubs could double hand hygiene adherence? A Pennsylvania hospital’s creative shake-up of its infection prevention program shows that sometimes it takes more than soap to get hands clean—and keep them that way.
Broadening the Path: Diverse Educational Routes Into Infection Prevention Careers
July 4th 2025Once dominated by nurses, infection prevention now welcomes professionals from public health, lab science, and respiratory therapy—each bringing unique expertise that strengthens patient safety and IPC programs.
How Contaminated Is Your Stretcher? The Hidden Risks on Hospital Wheels
July 3rd 2025Despite routine disinfection, hospital surfaces, such as stretchers, remain reservoirs for harmful microbes, according to several recent studies. From high-touch areas to damaged mattresses and the effectiveness of antimicrobial coatings, researchers continue to uncover persistent risks in environmental hygiene, highlighting the critical need for innovative, continuous disinfection strategies in health care settings.