This project is to establish an archival site for the data and programming code for a publication in Frontiers Bioengineering and Biotechnology, which can be accessed at : Waugh RE, Lomakina E, Amitrano A and Kim M (2023), Activation effects on the physical characteristics of T lymphocytes. Front. Bioeng. Biotechnol. 11:1175570. doi: 10.3389/fbioe.2023.1175570 The physical characteristics of leukocytes can affect their ability to traverse the microvasculature and may affect their systemic distribution and their interactions with the endothelium in different tissues. Emerging clinical treatments using cell therapeutics involve activation of T cells in vitro before reinfusion to treat disease. Activation causes significant changes in the size and physical behavior of T lymphocytes that could affect their effectiveness as therapeutic agents. The goal of this study was to measure and document these physical changes. The physical characteristics of leukocytes has been described as that of a highly viscous fluid droplet, having a contractile cortical tension at the cell periphery and an interior that flows in response to applied forces. The resistance of the interior to flow is characterized in terms of the cell viscosity. It has been observed that this resistance to flow decreases with increasing rate of flow, a phenomenon called shear thinning. To interpret our measurements, we developed a theoretical framework for a shear shinning fluid droplet with a constant cortical tension. For this part of the model there are three characteristic quantities that can be derived from the experiments: The cortical tension, the characteristic viscosity and the shear thinning coefficient. One aspect of cell behavior that is not predicted by the liquid droplet model is that there is a rapid initial entry of the cell into the pipette when it is aspirated at a constant pressure. This initial entry is thought to represent an elastic response of the cell, but a formal treatment of the cell mechanics that includes this behavior for large cellular deformations is yet to be formulated at the time of this posting. We address this aspect of cell behavior phenomenologically in terms of the length of the initial cell projection in the pipette. Details of our theoretical analysis and results are submitted for publication in Frontiers in Bioengineering and Biotechnology. The original data, MatLab code for analysis of the data, spreadsheets for further refinement of the data and tabulated results are contained in the files associated with this project. There are three types of Excel spreadsheets: one contains the primary measurements of each cell and includes the cell number (designation), the cortical tension Tcort (in N/m), the radius of the cell before aspiration R0 (um), the radius of the micropipette Rp (um), The aspiration pressure Pasp (Pa), the total length of the cell when it is fully aspirated into the pipette Ltot (um), and the total time it took for the cell to enter the pipette Ttot (s), followed by the time course of entry consisting of ordered pairs of time (s) and projection length Lp (um). These files are read by the accompanying MatLab code, which uses nonlinear regression to fit the data to the theory and produce fitted values for viscosity, an initial entry time constant, and the size of the initial entry Linit. These are named by the type of cells that were measured and the date of the experiment, e.g. Tcells-Jun12, or ActCD8-Dec2. There are 27 of these files, one for each day on which data were obtained. The second spreadsheet contains the tabulated output from the MatLab code including the fitted coefficients, their 95% confidence intervals and coefficients of variation, and other parameters calculated in the code. There are four of these workbooks one for each type of cell population: Tcells_MatLab-FR, CD8+_MatLab-FR, activ-Tcells_MatLab-FR, and activ-CD8+_MatLab-FR. There is a sheet for each experimental date. These sheets contain the MatLab output for the corresponding data file at different values of the power-law coefficient b. The best value of b for each day of experiment is determined to the right of the MatLab output. (See manuscript.) The output for the best b values for each day are tabulated in the sheet labeled "Best-b". In that spreadsheet, there are also tabulations of how different parameters, Linit, Volume and Lamtipinit change for different aspiration pressures. The final sheet is labeled Summary, and contains tabulated results and fitted curves for the cell volume, Linit, and lamtipinit, as functions of pressure. There is only one of the third type of spreadsheet, Data-Final-FR. Here we collect all of the values of indivudual parameters from the Best-b pages of the MatLab workbooks for performing statistical (ANOVA) analysis and generating figures for the manuscript.