AFM Analysis of Morphological Structure and Biomechanics of Human T cells under Different Stimulated Activations

The antigen recognition and activation of T cells has a central role in the immune response,which can directly affect the efficiency and the result of immune response. Morphological structure and mechanical properties of cells determines their function. Using atomic force microscope( AFM),the morphological structures and biomechanical properties of the resting T cells,the PHA activated T cells and the SEA activated T cells were detected at the nanoscale and Newton level. It was indicated that the resting T cells with round shape,the cell surface was relatively smooth and uniform. The cell height and the volume were increased after being activated. The volume of activated T cells increased for2 ~ 3 times of resting T cells and the height increases about 50%. Furthermore,high-resolution AFM images showed that the surface average roughness( R a) of activated T cells also increased. Interestingly, some particle clusters( 100 nm ~1 μm) are found in the activated T cell membrane. Clustering of cell surface receptors into micro/nano-domains in the plasma membrane was an important mechanism for regulating cellular functions. Compared with resting T cells,the adhesion force of activated T cells increased significantly,but the stiffness decreased. The changes of mechanical properties of T cells are beneficial to eliminate pathogens. These findings provide new insights into the T cell structure,function and ultimate immune response.