Oxford Immunotec Global PLC is a global, high-growth diagnostics company. We bring energy and invention to a world in need of diagnostic truth.
Our leading product, the T-SPOT®.TB test, is used for diagnosing infection with Tuberculosis, the world’s largest cause of death from infectious disease.
The Human Immune System
The human immune system is composed of three principle branches: Innate Immunity, Cellular (or T cell) Immunity and Humoral (or B cell) Immunity.
Despite these three branches and the multitude of immune cell types, the diagnostic world has only largely embraced antibodies. Leveraging our T-SPOT technology, Oxford Immunotec is one of the few companies to focus on standardising T cell and innate immunity measurements. Our T-SPOT technology gives us a unique toolbox to develop proprietary tests based on prosecuting the previously unexploited T cell and innate immunity branches of the immune system.
Our proprietary T-SPOT technology measures immune cell responses at a single cell level. Our technology studies the responses of living T cells and innate immune cells, which gives us a direct window into the immune system.
Simplistically, the technology starts with a blood sample obtained through a standard blood collection tube from which white blood cells, or WBC’s, are separated and purified. The cells are quantified and placed into specially designed plates where they are challenged with antigens specific to the disease under study. Disease-specific cells responding to these antigens will release immune messenger molecules, called cytokines. We then use chemistry to allow us to visualise those WBCs releasing cytokines (and hence those which react to the antigen), resulting in a spot on the bottom of the plate, corresponding to the footprint of an individual reacting WBC. Finally, we use an automated image analysis system to identify and count each of these spots to give a quantitative readout. That quantitative readout gives us the frequency of responsive disease-specific cells.
The exquisite sensitivity afforded by single-cell resolution is key to the platform’s applicability across different areas of medicine. This is because, for many conditions, the frequency of T cells or innate immune cells can be very low. Our technology has the ability to detect an individual reacting cell in a population of 250,000 white blood cells.
Because we always standardise the number of cells used in each assay, we can compare responses over time to a common standard. It is this normalisation of the sample that makes longitudinal measurement valid and the platform well-suited for monitoring applications.
The sensitivity of the T-SPOT platform, as well as its use for monitoring applications, are two of many reasons why this technique has key advantages over other technologies, such as ELISA.
About the T-SPOT.TB Test
The T-SPOT.TB test is a single-visit blood test for TB screening and is one of only two recommended alternatives to the tuberculin skin test (TST) – otherwise known as purified protein derivative (PPD) test, or the Mantoux test. The T-SPOT.TB test is available in over 50 countries including Europe, China, Japan, and the US, and is recognized by the WHO as one of the 100 essential diagnostic tests that should be available in every country. The T-SPOT.TB test uses a standardized sample, reducing the influence of factors in the blood which may affect performance, and normalizing for cell number variation.
The test has been shown to have a sensitivity of 95.6% and a specificity in excess of 97.1% and is able to maintain performance even in samples otherwise difficult to test, such as samples from immunosuppressed patients. The T-SPOT.TB test does not cross-react with the BCG vaccine. Automation of the T-SPOT.TB test is possible using the T-Cell Select reagent kit. Automation solutions are available for the low, medium, and high throughput settings2. The T-Cell Select reagent kit also enables samples to be stored at ambient temperature for up to 54 hours after blood is collected.
About Oxford Immunotec
Oxford Immunotec Global PLC is a global, high-growth diagnostics company. We bring energy and invention to a world in need of diagnostic truth. Our leading product, the T-SPOT.TB test is used for diagnosing infection with Tuberculosis, the world’s largest cause of death from infectious disease. The T-SPOT.TB test has been approved for sale in over 50 countries, including the United States, where it has received pre-market approval from the Food and Drug Administration, Europe, where it has obtained a CE mark, as well as Japan and China.