RECEPTOR MEDIATED T CELL ACTIVATION

先前的激活历史对克隆细胞随后反应的影响 检查T辅助性1（Thl）细胞对TCR介导的刺激的反应。 Thl细胞 通过单独用IL 2刺激或通过用 特异性抗原和APC。 细胞在两个 条件增殖等同于抗-CD 3抗体的应答。 然而，抗CD 3诱导强烈的磷脂酰肌醇（PI）水解 而[Ca++]i仅在维持了 用特异性抗原+ APC刺激既不产生PI，也不产生Ca++ 应答 因此，Thl细胞利用的信号传导途径是 受先前通过TCR的刺激的影响。 内源性超抗原诱导的信号转导途径 T细胞的刺激用克隆的和异质的 反应性T细胞 结果发现，PI水解和增加 [CA++]i由携带Mls（a）（mtv-7）超抗原的APC诱导。 使用 TCR转基因小鼠进一步证明，在表达TCR的小鼠中， Mls（a）作为自身抗原，在小鼠中未诱导Mls（a）特异性应答。 外周T细胞;相反，胸腺细胞对自身Mls有反应（a）， 结合物形成和[Ca++]i增加，表明未成熟的 在负选择之前，胸腺细胞特异性地对自身免疫应答。 超抗原

The effect of prior activation history on subsequent responses of cloned T helper 1 (Thl) cells to TCR-mediated stimuli was examined. Thl cells were maintained by stimulation with IL2 alone or by stimulation with specific antigen and APC in addition to IL2. Cells carried under both conditions proliferated equivalently in responses to anti-CD3 antibody. However, anti-CD3 induced strong phosphatidyl inosotol (PI) hydrolysis and increased [Ca++]i only in cells that had been maintained by stimulation with specific antigen + APC gave neither PI nor Ca++ responses. The signaling pathways utilizing by Thl cells were thus influenced by prior stimulation through the TCR. Signal transduction pathways induced by endogenous superantigen stimulation of T cells were analyzed with both cloned and heterogeneous responding T cells. It was found that both PI hydrolysis and increased [CA++]i were induced by Mls(a) (mtv-7) superantigen-bearing APC. Using TCR transgenic mice it was further demonstrated that in mice expressing Mls(a) as a self antigen, no Mls(a)-specific response was induced in peripheral T cells; in contrast thymocytes did respond to self Mls(a) by conjugate formation and increased [Ca++]i, demonstrated that immature thymocytes, prior to negative selection, respond specifically to self superantigen.