T Cell Responder

* Protective immunity to SARS-CoV-2, like other viruses, depends on a combined immune response by specific antibodies and T lymphocytes. As we race to immunise the world and end the pandemic, there is considerable unmet need for better, high-throughput immune monitoring. In diverse settings, from healthcare and public health planning to travel and hospitality, there is demand to know if people are carrying immunity. These answers also impact if and when people will require vaccine boosters. While the increased momentum behind antibody testing has supplied finely-tuned, cost-effective, reliable tests, T lymphocyte assays remain cumbersome, costly and limited to specialist labs. The team at Imperial College are leaders in T lymphocyte immunology and have, since the start of the pandemic, been at the forefront of characterising immunity to the virus. However, the assays involve complex cell separations and equipment. We have invested considerable effort in defining which aspects of immunity are truly specific to SARS-CoV-2 and not the result of cross-reactivity with the related common cold viruses. Recent work has been devoted to reimagining T lymphocyte assays to consider what it would take to demonstrate, rapidly, that a small blood sample contains specific cells responding to the virus - that is, who can be defined as having immune memory for this virus - 'a T cell responder'. We have been able to show novel biomarkers of the response, measurable in immune people in a matter of hours. During this project we plan to refine our observations to the extent of producing a pilot point-of-care test that can be developed as a test of T lymphocyte immunity. We envisage utilisation in many settings: international immunity certificates, management of optimal vaccine schedules in at-risk patient groups, public health decisions on when to boost vaccines. Once optimised, the approach can easily be extended to other settings, from immunity to other pathogens, to monitoring of the anti-tumour response in cancer patients given immunotherapy. For these reasons, we have given the project and proposed kit an easy and self-explanatory name - 'T Cell Responder'.