Research shows link between T-cells & ageing

New Delhi : Researchers have discovered a correlation between ageing and the effectiveness of T-cells, a type of cell that is a part of our immune system which is programmed to fight or kill a threat.
The researchers found that older people have T-cells that are less effective at fending off the hepatitis C virus (HCV). The research, published in Science Translational Medicine, is based on a novel technique, called iTAST (in situ TCR affinity and sequence test), that is able to measure a T-cell's so-called affinity, a physical parameter that determines how well T-cell receptors recognize and bind to their antigens, such as those derived from bacteria, viruses or cancer cells. If a person has low-affinity T-cells for a specific virus, the body won't mount an effective fight against the virus. High-affinity T-cells, on the other hand, can launch strong fights against diseases and illnesses such as cancer and diabetes.
Led by biomedical engineering Assistant Professor Jenny Jiang, a team of researchers invented and tested iTAST at University of Texas at Austin. The team's experiments focused on measuring a group of donors' T-cell affinity for HCV. They were surprised to find a stark difference between the HCV-specific T-cells of older and younger donors. "T-cell affinity is a parameter that can gauge how healthy your immune system is toward a specific antigen," said Jiang, the senior author on the paper. We found that as you grow older, your T-cells capable of recognizing some of the viruses that you haven't encountered before become progressively lower in affinity. ITAST is a three-part process that can isolate T-cells, measure T-cell affinity and sequence T-cell receptor genes, all in one day. The other techniques used to measure the T-cell affinity of just one cell are extremely labour intensive and time consuming, sometimes taking up to a year. In the health care arena, the technique could be useful in evaluating the health status of an individual or in adoptive immunotherapy - a nascent field of medicine in which physicians tailor therapies and dosages for individual patients to rev up the body's defences.
In some immunotherapy methods, synthetic T-cell receptor genes that can recognize cancer cells are added to T-cells and then transferred back into the body. Although immunotherapy is a promising field, there have been examples where these genetically engineered T-cells cause dangerous unintended reactions in the body and even deaths. What we are doing is isolating T-cells from a patient," said Shuqi Zhang, a UT Austin chemical engineering graduate student and lead author on the paper.
"They are the patient's own cells, so iTAST is potentially a way to isolate safe high-affinity T-cells for adoptive immunotherapy. In the researcher's first deployment of iTAST, they were able to demonstrate that there is a link between aging and T-cell affinity. It's common knowledge that as people age, they are more susceptible to illness and less responsive to vaccines. But, for now, scientists and engineers say our understanding of immune aging is incomplete. "This is an important discovery," Zhang said.

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