New York:Immune cells of older people are less likely to be effective at fending off the hepatitis C virus (HCV), finds a new study suggesting a correlation between ageing and the effectiveness of T-cells. Using a novel technique called iTAST (in situ TCR affinity and sequence test), the team measured a group of donors' T-cell's affinity -- a physical parameter that determines how well the immune cell receptors recognise and bind to their antigens -- for HCV. If a person has low-affinity T-cells for a specific virus, the body won't mount an effective fight against the virus. However, high-affinity T-cells can launch strong fights against diseases and illnesses such as cancer and diabetes. "T-cell affinity is a parameter that can gauge how healthy your immune system is toward a specific antigen," said lead author Jenny Jiang, Assistant Professor, at the University of Texas, in the US. The findings showed a stark difference between the HCV-specific T-cells of older and younger donors. "The study found that as one grows older, the T-cells capable of recognising some of the viruses become progressively lower in affinity," Jiang added. iTAST is the first technique capable of retrieving and measuring the affinity of a large volume of T-cells and their correlated receptor sequences from an individual, the researchers said in the paper published in the journal Science Translational Medicine. "What we are doing is isolating T-cells from a patient. They are the patient's own cells, so iTAST is potentially a way to isolate safe high-affinity T-cells for adoptive immunotherapy," explained Shuqi Zhang, Graduate Student at the University of Texas. ITAST's abiIlity to identify and retrieve a person's high-affinity T-cells could benefit immunotherapy and vaccine development, resulting in improved personalised medicine and therapies, the researchers noted.