RT Journal Article SR Electronic T1 Label-free identification of non-activated lymphocytes using three-dimensional refractive index tomography and machine learning JF bioRxiv FD Cold Spring Harbor Laboratory SP 107805 DO 10.1101/107805 A1 Jonghee Yoon A1 YoungJu Jo A1 Min-hyeok Kim A1 Kyoohyun Kim A1 SangYun Lee A1 Suk-Jo Kang A1 YongKeun Park YR 2017 UL http://biorxiv.org/content/early/2017/02/11/107805.abstract AB Identification of lymphocyte cell types is crucial for understanding their pathophysiologic roles in human diseases. Current methods for discriminating lymphocyte cell types primarily relies on labelling techniques with magnetic beads or fluorescence agents, which take time and have costs for sample preparation and may also have a potential risk of altering cellular functions. Here, we present label-free identification of non-activated lymphocyte subtypes using refractive index tomography. From the measurements of three-dimensional refractive index maps of individual lymphocytes, the morphological and biochemical properties of the lymphocytes are quantitatively retrieved. Machine learning methods establish an optimized classification model using the retrieved quantitative characteristics of the lymphocytes to identify lymphocyte subtypes at the individual cell level. We show that our approach enables label-free identification of three lymphocyte cell types (B, CD4+ T, and CD8+ T lymphocytes) with high specificity and sensitivity. The present method will be a versatile tool for investigating the pathophysiological roles of lymphocytes in various diseases including cancers, autoimmune diseases, and virus infections.