In a new study entitled “The use of Wavelength Modulated Raman Spectroscopy in label-free identification of T lymphocyte subsets, Natural Killer cells and Dendritic cells” researchers developed a new method, Wavelength Modulated Raman Spectroscopy, that can specifically identify immune cells without the need to destroy the cells in the process, opening the possibility of rapid detection of leukaemias and lymphomas from a small blood sample. The study was published in the journal PLOS One.
The immune system is characterized by a panoply of immune cells that circulate in the blood. The traditional method of identifying immune cells has relied on the label of such cells with fluorescent markers that recognize specific proteins at the cells’ surface, or alternatively to stain cells, which involves its inevitable destruction.
In this study a research team at the University of St Andrews developed a completely label-free method to identify immune cells using a light scattering technique called Wavelength Modulated Raman Spectroscopy (WMRS). This technique allows the rapid identification of immune cells without killing the cells or altering their properties.
With subtle changes to the basal technique, the Raman Spectroscopy technique is based on the principle that the frequency of photons present at a monochromatic light, such as that from a laser source, changes upon contact with a sample; this absorbs the photons and then reemits them at a different frequency, either shifted up or down when compared to the original monochromatic frequency, called the Raman effect. Slightly changing the incident laser light producing an alteration to the Raman signal, allowed researchers to identify with greater accuracy immune cells extracted from healthy human donors.
Study author Dr. Simon Powis noted, “Under a normal light microscope these immune cells essentially all look identical. With this new method we can identify key cell types without any labelling. Our next goal is to make a full catalogue of all the normal cell types of the immune system that can be detected in the bloodstream. Once we have this completed, we can then collaborate with our clinical colleagues to start identifying when these immune cells are altered, in conditions such as leukaemia and lymphoma, potentially providing a rapid detection system from just a small blood sample.”