Sanchez-Garcia J, Atkins C, Pasvol G, Wilkinson R J, Colston M J
National Institute for Medical Research, London, UK.
Immunology. 1996 Oct;89(2):213-9. doi: 10.1046/j.1365-2567.1996.d01-729.x.
Activation of lymphocytes leads to the modulation of a number of surface molecules. We have investigated the expression of one such molecule. L-selectin, following activation of gamma delta T cells with Mycobacterium tuberculosis. L-selectin is modulated during lymphocyte entry into lymph nodes; this modulation reflects the recirculation and homing potential of lymphocytes. We find that stimulation of gamma delta T cells by M. tuberculosis antigens results in shedding of L-selectin from gamma delta T cells. Re-expression of L-selectin occurs on removal of antigen suggesting that the regulation of expression is controlled by the presence or absence of antigen. The gamma delta T-cell receptor (TCR)-positive, L-selectin negative population of peripheral blood lymphocytes appears to be resting cells, as assessed by forward- and light-scatter analysis. We further find that gamma delta T cells isolated from a site of infection, the pleural fluid of a tuberculosis patient, are L-selectin negative, and that L-selectin is re-expressed following culture of the pleural fluid gamma delta T cells in the absence of antigen. These results demonstrate that, in addition to stimulation with polyclonal mitogens, antigen stimulation can also promote the surface shedding of L-selectin and that gamma delta T cells have the potential to home to sites of infection supporting their role in the immunological defence against infectious micro-organisms.
淋巴细胞的激活会导致多种表面分子的调节。我们研究了其中一种分子——L-选择素在结核分枝杆菌激活γδT细胞后的表达情况。L-选择素在淋巴细胞进入淋巴结的过程中会发生调节；这种调节反映了淋巴细胞的再循环和归巢潜能。我们发现结核分枝杆菌抗原刺激γδT细胞会导致L-选择素从γδT细胞上脱落。去除抗原后L-选择素会重新表达，这表明表达的调节受抗原存在与否的控制。通过前向散射和光散射分析评估，外周血淋巴细胞中γδT细胞受体（TCR）阳性、L-选择素阴性的群体似乎是静止细胞。我们还发现，从感染部位（一名肺结核患者的胸腔积液）分离出的γδT细胞是L-选择素阴性的，并且在无抗原的情况下培养胸腔积液γδT细胞后，L-选择素会重新表达。这些结果表明，除了用多克隆有丝分裂原刺激外，抗原刺激也能促进L-选择素的表面脱落，并且γδT细胞具有归巢到感染部位的潜能，这支持了它们在针对感染性微生物的免疫防御中的作用。
