Activation-induced Reorganization in Membrane Nanostructures and Alteration in Adhesion of CD4 + T Lymphocytes Exploited by AFM/LFM

Yangzhe      Wu; Yi      Hu; Jianan      Chen; Jiye      Cai; Xianhui      He

Abstract

To date, the activation induced reorganization in membrane nanostructures and alteration in membrane adhesion property of CD4 + T lymphocytes largely remain unclear yet even though their immunological functions have been well elucidated. The present work focused on detecting the differences in topography, membrane nanostructures and adhesion/friction behaviors of CD4 + T cells in the absence and presence of stimulus (Phorbol dibutyrate, PDB, plus Ionomycin, ION). The results showed that, due to cell activation in vitro, (a) the formation of pseudopodia, lamellipodia; (b) the appearance of membrane pores with 200∼450 nm in diameter and 70∼110 nm in depth; (c) the formation of nanostructural domains with different adhesion behavior; (d) the loading rate and loading force could affect the measured adhesion force nonlinearly; (e) the dynamic changes in membrane adhesion force, from 348±9.08 pN for resting cells, 827.07±24.61 pN for 24 hours of activation, 372.87±9.26 pN for 48 hours of activation, to 302.45±11.42 pN for 72 hours of activation. This work achieved the biophysical changes of CD4 + T cells with and without stimulation, which would enable us to seek new implications and potential links between cytoarchitectures, membrane adhesion and immunological functions at the single-cell and nanoscale level.

Keywords: CD4 + T lymphocytes, cell activation, membrane nanostructures, adhesion behavior, force microscopy, in vitro, topography, lateral force, force curves, atomic force microscope, lateral force microscope