中文摘要：

T细胞的抗原识别和活化可以直接影响整个免疫应答的性质、效能和结果,在人体免疫反应中具有核心作用.细胞的形态结构和力学特性决定着细胞的功能的发挥.利用原子力显微镜（AFM）从纳米水平和皮牛顿量级探测分析静息的T细胞和不同刺激剂（超抗原SEA和植物凝集素PHA）活化的T细胞的形态结构和生物力学特性.研究发现静息的T细胞呈较为规则的圆形,细胞表面相对光滑均一,活化后细胞高度和体积明显增大,体积增大为静息T细胞的2~3倍,高度增加了约50%,这是T细胞经过刺激剂活化后增殖、分化而增大的表现.同时发现活化后的T细胞表面粗糙度增大,细胞表面形成100 nm~1 μm颗粒状团簇结构.这种微纳结构域的形成与T细胞经过活化后细胞表面分子表达和细胞因子的分泌有关,并且与免疫突触的形成和功能发挥密切关联.经过PHA和SEA活化后的T细胞表面粘附力增大,是静息的T细胞的3-6倍,而细胞硬度明显减小,这种力学特性的变化有利于T细胞与病原体的相关作用从而清除病原体.通过AFM的研究,可以进一步的了解T淋巴细胞形态变化与细胞行为之间的关系,为更好地理解T细胞的结构与功能提供了更多可视化的依据.

英文摘要：

The antigen recognition and activation of T cells has a central role in the immune response, which can di- rectly 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 biomechanieal prop- erties 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 uni- form. The cell height and the volume were increased after being activated. The volume of activated T cells increased for 2 - 3 times of resting T cells and the height increases about 50%. Furthermore, high-resolution AFM images showed that the surface average roughness （Ra） 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 miero/nano-do- mains 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 charlges of mechan- ical properties of T cells are beneficial to eliminate pathogens. These findings provide new insights into the T cell struc- ture, function and ultimate immune response.