Gur H, Wacholtz M C, Davis L S, Geppert T D, Lipsky P E
Harold C. Simmons Arthritis Research Center, Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas 75235.
Cell Immunol. 1992 Mar;140(1):81-96. doi: 10.1016/0008-8749(92)90178-r.
The role of cross-linking the TCR/CD3 complex in the induction of T cell activation was examined using human peripheral blood T cells and the Jurkat leukemic T cell line. IL-2 production was induced from these cells by pulsing them with mAb to CD3 and costimulating with phorbol myristate acetate (PMA). Cross-linking the anti-CD3 mAb with soluble goat anti-mouse immunoglobulin (GaMIg) markedly inhibited IL-2 production by these cells. Soluble GaMIg did not induce a generalized inhibition of IL-2 production as it was required for responses induced by mAb to class I MHC molecules. In addition, cross-linking anti-CD3 mAb with GaMIg did not inhibit IL-2 production induced by PMA and ionomycin. Inhibition of IL-2 production induced by soluble GaMIg reflected diminished accumulation of mRNA for IL-2. By contrast, immobilized GaMIg was a potent stimulus for IL-2 production by T cells pulsed with anti-CD3 mAb and costimulated with PMA. Cross-linking anti-CD3 with soluble GaMIg induced enhanced aggregation of the ligated molecules, but it did not alter the profile of the change in intracellular calcium induced. To determine whether cross-linking of mAb played a role in inducing IL-2 production as well as in limiting responsiveness, F(ab) fragments were employed. F(ab) fragments of anti-CD3 mAb failed to induce IL-2 production by PMA costimulated Jurkat cells. However, cross-linking of anti-CD3 F(ab)-pulsed Jurkat cells with low concentrations of soluble GaMIg induced IL-2 production in the presence of PMA, whereas higher concentrations suppressed responses. The data indicate that induction of IL-2 production requires aggregation of the TCR/CD3 complex, whereas excessive cross-linking diminishes the induction of IL-2 production. Moreover, the results indicate that various biologic activities of the CD3 molecular complex, including aggregation, signaling capability, and the ability to induce IL-2 gene transcription, are differentially affected by cross-linking.
利用人外周血T细胞和Jurkat白血病T细胞系，研究了TCR/CD3复合物交联在诱导T细胞活化中的作用。用抗CD3单克隆抗体刺激这些细胞并用佛波醇肉豆蔻酸酯乙酸酯（PMA）共刺激，可诱导这些细胞产生白细胞介素-2（IL-2）。用可溶性山羊抗小鼠免疫球蛋白（GaMIg）使抗CD3单克隆抗体交联，可显著抑制这些细胞产生IL-2。可溶性GaMIg不会诱导对IL-2产生的普遍抑制，因为它是抗I类主要组织相容性复合体分子单克隆抗体诱导反应所必需的。此外，用GaMIg使抗CD3单克隆抗体交联不会抑制PMA和离子霉素诱导的IL-2产生。可溶性GaMIg诱导的IL-2产生抑制反映了IL-2 mRNA积累的减少。相比之下，固定化的GaMIg是用抗CD3单克隆抗体刺激并用PMA共刺激的T细胞产生IL-2的有效刺激物。用可溶性GaMIg使抗CD3交联可诱导连接分子的聚集增强，但不会改变诱导的细胞内钙变化的特征。为了确定单克隆抗体的交联在诱导IL-2产生以及限制反应性方面是否起作用，使用了F(ab)片段。抗CD3单克隆抗体的F(ab)片段不能通过PMA共刺激的Jurkat细胞诱导IL-2产生。然而，在PMA存在的情况下，用低浓度可溶性GaMIg使抗CD3 F(ab)刺激的Jurkat细胞交联可诱导IL-2产生，而较高浓度则抑制反应。数据表明，IL-2产生的诱导需要TCR/CD3复合物的聚集，而过度交联会减少IL-2产生的诱导。此外，结果表明，CD3分子复合物的各种生物学活性，包括聚集、信号传导能力以及诱导IL-2基因转录的能力，受到交联的影响各不相同。
