Aoki Y, Yoshikai Y
Research Institute for Disease Mechanism and Control, Nagoya University School of Medicine, Showa-ku, Aichi, Japan.
Microbiol Immunol. 1997;41(4):337-43. doi: 10.1111/j.1348-0421.1997.tb01210.x.
Superantigens are known to induce clonal anergy and/or deletion in reactive T cells peripherally. This study was undertaken to investigate the T-cell status early after exposure to staphylococcal enterotoxin A (SEA) in vivo and in vitro. At the peak of clonal expansion following the administration of 5 microg SEA (i.e., 2 days after the injection), C57BL/6 mice were rechallenged with the same dose of SEA in vivo. The secondary stimulation augmented clonal expansion of the T cells bearing Vbeta3 and Vbeta11 in both CD4+ and CD8+ populations. In vitro restimulation of the spleen cells taken from the SEA-primed mice also induced further expansion of the Vbeta3+ T cells during 2 days of culturing, whereas without restimulation, a marked reduction of Vbeta3+ T cells occurred. The spleen cells from the SEA-primed mice were hyper-reactive to in vitro restimulation with SEA as measured by 3H-TdR uptake on day 1 of culturing, but augmented proliferation leveled off thereafter. By day 3, the values of 3H-TdR uptake were less than 20% of those of the controls in which spleen cells from native mice were stimulated with SEA in vitro. These results suggest that T cells exposed to SEA in vivo are still capable of proliferating upon SEA rechallenge, but subsequently, the proliferation starts to wane.
已知超抗原可在外周诱导反应性T细胞的克隆无能和/或缺失。本研究旨在调查在体内和体外暴露于葡萄球菌肠毒素A（SEA）后早期的T细胞状态。在给予5微克SEA后克隆扩增的高峰期（即注射后2天），对C57BL/6小鼠在体内再次给予相同剂量的SEA。二次刺激增强了CD4+和CD8+群体中携带Vβ3和Vβ11的T细胞的克隆扩增。对取自SEA致敏小鼠的脾细胞进行体外再刺激，在培养2天期间也诱导了Vβ3+T细胞的进一步扩增，而未经再刺激时，Vβ3+T细胞显著减少。通过培养第1天的3H-TdR摄取量测定，取自SEA致敏小鼠的脾细胞对SEA体外再刺激反应过度，但此后增殖增强趋于平稳。到第3天，3H-TdR摄取值不到用SEA体外刺激天然小鼠脾细胞的对照组的20%。这些结果表明，在体内暴露于SEA的T细胞在SEA再次攻击时仍有增殖能力，但随后增殖开始减弱。
