Evidence of synergy between Thy-1 and CD3/TCR complex in signal delivery to murine thymocytes for cell death.
Evidence of synergy between Thy-1 and CD3/TCR complex in signal delivery to murine thymocytes for cell death.
复制标题
Thy-1 和 CD3/TCR 复合物在向小鼠胸腺细胞传递信号以导致细胞死亡方面具有协同作用的证据。
作者：
I. Nakashima;Y. Zhang;S. Rahman;T. Yoshida;K. Isobe;L. Ding;T. Iwamoto;M. Hamaguchi;H. Ikezawa;R. Taguchi
研究了Thy-1在CD 3/TCR复合物介导的小鼠胸腺细胞信号传递中的潜在作用。模拟Ag的交联抗CD 3 mAb刺激来自成年（6至8周龄）小鼠的胸腺细胞悬浮液，导致细胞质游离钙离子（[Ca 2 +]i）迅速升高，磷酸肌醇产生水平较低，110/120-kDa和40-kDa细胞蛋白酪氨酸特异性磷酸化略有增加。模拟假定的天然配体的交联抗Thy-1 mAb也诱导了弱但持续的[Ca 2 +]i升高、低磷酸肌醇产生和弱蛋白酪氨酸磷酸化。然而，通过这两种途径中的任何一种传递的信号都不足以明确促进成体胸腺细胞的细胞死亡和DNA片段化。在此，我们证明了抗Thy-1 mAb与抗CD 3 mAb协同诱导持久显著的[Ca 2 +]i升高，明确的肌醇1，4，5-三磷酸和肌醇1，3，4，5-四磷酸产生，以及110/120-、92-、75-和40-kDa蛋白的广泛酪氨酸特异性磷酸化，这导致在成体胸腺细胞中显著促进细胞死亡和DNA片段化。这种独特的抗Thy-1抗体活性被证实针对糖基磷脂酰肌醇锚定的Thy-1，并且与以不同方式增强CD 3介导的信号转导的已知抗L3 T4活性不同。抗-CD 3和抗-Thy-1 mAb的协同作用强制性地需要两种mAb交联在一起。交联在一起的抗CD 3和抗Thy-1 mAb作用于新生小鼠（出生后不到24 h）的未成熟胸腺细胞，从而更广泛地促进蛋白酪氨酸磷酸化和细胞死亡。此外，它们影响外周T淋巴细胞加速蛋白酪氨酸磷酸化，但不影响细胞死亡。这些结果表明，糖基磷脂酰肌醇锚定的Thy-1作为一种可能的独特的胸腺内增强剂的CD 3/TCR复合物传递的信号负胸腺细胞选择的新功能。
The potential role of Thy-1 in CD3/TCR complex-mediated signal delivery to murine thymocytes was studied. Ag-mimicking cross-linked anti-CD3 mAb stimulated suspension of thymocytes from adult (6 to 8 wk old) mice for a brisk free cytoplasmic calcium ion ([Ca2+]i) rise, low level of inositol phosphate production, and marginal increase in tyrosine-specific phosphorylation of 110/120-kDa and 40-kDa cellular proteins. Weak but sustained [Ca2+]i rise, low inositol phosphate production, and weak protein tyrosine phosphorylation were also induced by the cross-linked anti-Thy-1 mAb that mimicked the putative natural ligand. The signal delivered via either of these two pathways was however insufficient for definitively promoting cell death and DNA fragmentation in the adult thymocytes. Here we demonstrated that anti-Thy-1 mAb synergized with anti-CD3 mAb for inducing a long-lasting prominent [Ca2+]i rise, definite inositol 1,4,5-triphosphate and inositol 1,3,4,5-tetrakiphosphate production, and extensive tyrosine-specific phosphorylation of 110/120-, 92-, 75-, and 40-kDa proteins, which resulted in marked promotion of cell death and DNA fragmentation in the adult thymocytes. This unique anti-Thy-1 antibody activity was confirmed to be directed to glycosylphosphatidylinositol-anchored Thy-1, and was distinguished from the known anti-L3T4 activity that augmented the CD3-mediated signal transduction in a different manner. The synergistic actions of anti-CD3 and anti-Thy-1 mAb obligatorily required the cross-linking of the two mAb together. The anti-CD3 and anti-Thy-1 mAb cross-linked together acted on immature thymocytes from newborn (less than 24 h after birth) mice for rather more extensive promotion of protein tyrosine phosphorylation and cell death. In addition, they affected peripheral T lymphocytes for accelerating protein tyrosine phosphorylation but not cell death. These results suggest a novel function of glycosylphosphatidylinositol-anchored Thy-1 as a possible unique intrathymic intensifier of the CD3/TCR complex-delivered signal for negative thymocyte selection.