Braakman E, van de Winkel J G, van Krimpen B A, Jansze M, Bolhuis R L
Department of Immunology, Daniel den Hoed Cancer Center, Rotterdam, The Netherlands.
Cell Immunol. 1992 Aug;143(1):97-107. doi: 10.1016/0008-8749(92)90008-d.
We examined the expression, the signal transduction capacity and mouse IgG-isotype specificity of CD16 on human gamma delta T cells. CD16 is expressed by the majority of gamma delta T cells in peripheral blood and by part of the gamma delta T cell clones. The amount of CD16 expressed on gamma delta T cell clones varied considerably with passaging of the cells, but was always significantly less than on freshly isolated gamma delta T cells. Like CD16 on CD3- CD16+ natural killer (NK) cells, CD16 on gamma delta T cells can act as an activation site triggering cytotoxic activity. CD16+ gamma delta T cell clones exerted antibody-dependent cellular cytotoxicity (ADCC) which could be blocked by anti-CD16 mAb. ADCC activity of gamma delta T cell clones was also inhibited by anti-CD3 mAb, suggesting a functional linkage between the CD16 and CD3 activation pathways. MAb directed against CD16 induced lysis of Fc gamma R+ target cells by CD16+ gamma delta T cell clones. The mouse IgG-isotype specificity of CD16 on gamma delta T cells was analyzed using isotype switch variants of a murine anti-glycophorin A mAb in EA rosette assays, and was found to be identical to that of CD16 on CD3- CD16+ NK cells, i.e., highest affinity for mIgG2a, intermediate affinity for mIgG2b, and undetectable binding of mIgG1-sensitized erythrocytes. CD16 was partly modulated from the cell surface of both gamma delta T cells and NK cells after rosette formation with mIgG2a-sensitized erythrocytes, indicating that the rosette formation was indeed mediated via the CD16 molecule.
我们检测了人γδT细胞上CD16的表达、信号转导能力及小鼠IgG同种型特异性。外周血中大多数γδT细胞及部分γδT细胞克隆表达CD16。γδT细胞克隆上表达的CD16量随细胞传代而有很大变化，但总是显著低于新鲜分离的γδT细胞。与CD3 - CD16 + 自然杀伤（NK）细胞上的CD16一样，γδT细胞上的CD16可作为触发细胞毒性活性的激活位点。CD16 + γδT细胞克隆发挥抗体依赖性细胞毒性（ADCC）作用，该作用可被抗CD16单克隆抗体阻断。抗CD3单克隆抗体也抑制γδT细胞克隆的ADCC活性，提示CD16和CD3激活途径之间存在功能联系。针对CD16的单克隆抗体诱导CD16 + γδT细胞克隆裂解FcγR + 靶细胞。在EA玫瑰花结试验中，使用鼠抗血型糖蛋白A单克隆抗体的同种型转换变体分析γδT细胞上CD16的小鼠IgG同种型特异性，发现其与CD3 - CD16 + NK细胞上的CD16相同，即对mIgG2a亲和力最高，对mIgG2b亲和力中等，对mIgG1致敏红细胞无明显结合。用mIgG2a致敏红细胞形成玫瑰花结后，CD16从γδT细胞和NK细胞的细胞表面部分下调，表明玫瑰花结形成确实是通过CD16分子介导的。
