Yeh E T, Reiser H, Daley J, Rock K L
J Immunol. 1987 Jan 1;138(1):91-7.
T-cell activating protein, TAP, is a Ly-6 encoded 12,000 dalton glycoprotein involved in the activation of murine T cells. TAP is distinct from other known surface activating structures, such as the T cell receptor/T3 complex and Thy-1. This study investigates the mechanism of activation via the TAP molecule. Soluble alpha TAP monoclonal antibody (MAb) is sufficient for T cell activation. This, however, requires cross-linking because F(ab) monovalent antibody is not stimulatory unless cross-linked by a second antibody. Immediately after cross-linking, there is a rapid influx of calcium, which is comparable with concanavalin A or T cell receptor triggered responses. Subsequently, interleukin 2 (IL 2) is produced, and IL 2 receptors (IL 2R) are expressed. TAP-stimulated T cell proliferation is driven by this autocrine pathway because it is inhibited by alpha IL 2R MAb. Thus TAP-mediated activation appears to share a common final pathway with other mitogenic stimuli. A nonactivating alpha TAP MAb was observed to stimulate T cells upon additional cross-linking. Given this observation, we asked whether other Ly-6 linked proteins might share similar activating potential. We show that at least three distinct Ly-6 linked molecules are capable of stimulating T hybrid clones and/or heterogeneous T lymphocytes. Thus it appears that the Ly-6 locus encodes a family of activating cell surface molecules.
T细胞激活蛋白（TAP）是一种由Ly-6编码的12000道尔顿糖蛋白，参与小鼠T细胞的激活。TAP与其他已知的表面激活结构不同，如T细胞受体/T3复合物和Thy-1。本研究探讨了通过TAP分子激活的机制。可溶性αTAP单克隆抗体（MAb）足以激活T细胞。然而，这需要交联，因为F(ab)单价抗体除非被第二种抗体交联，否则没有刺激作用。交联后立即有快速的钙流入，这与伴刀豆球蛋白A或T细胞受体触发的反应相当。随后，产生白细胞介素2（IL-2），并表达IL-2受体（IL-2R）。TAP刺激的T细胞增殖由这种自分泌途径驱动，因为它被αIL-2R MAb抑制。因此，TAP介导的激活似乎与其他有丝分裂原刺激共享一个共同的最终途径。观察到一种非激活的αTAP MAb在额外交联后能刺激T细胞。基于这一观察结果，我们询问其他Ly-6连接的蛋白质是否可能具有类似的激活潜力。我们表明，至少有三种不同的Ly-6连接分子能够刺激T杂交克隆和/或异质性T淋巴细胞。因此，Ly-6基因座似乎编码了一个激活细胞表面分子家族。
