Cardillo F, Nomizo A, Mengel J
Department of Immunology, Institute of Biological Sciences, University of São Paulo, SP, Brazil.
Int Immunol. 1998 Feb;10(2):107-16. doi: 10.1093/intimm/10.2.107.
We have previously shown that splenic gammadelta T cells from young but not aged BALB/c mice possess suppressor activity in vivo and in vitro during the acute phase of Trypanosoma cruzi infection. The present work was undertaken to investigate the suppressor activity of gammadelta T cells from T. cruzi-infected euthymic or athymic mice and the role of the thymus in modulating non-adherent spleen cell suppressor activity during the acute phase of infection. Splenic gammadelta T cells from aged or athymic BALB/c mice reconstituted with total spleen cells or non-reconstituted did not exhibit suppressor activity when added to full allogeneic, mixed lymphocyte cultures. In contrast, splenic gammadelta T cells from young euthymic BALB/c mice showed suppressor activity in vitro. Thymectomy reduced the splenic gammadelta T cell suppressor activity of young BALB/c mice in a time-dependent manner, following a T. cruzi challenge. The continuous provision of thymocytes to aged mice, young thymectomized mice or total spleen cell-reconstituted athymic mice could re-establish the gammadelta T cell suppressor activity. Of particular significance was the observation that the depletion of gammadelta T cells during the acute phase of T. cruzi infection restored the capacity of these mice to mount a humoral immune response to a non-related antigen such as ovalbumin. These results indicate that gammadelta T cells of extrathymic origin cannot mediate suppression and that the thymus has a role in the regulation of suppression during the acute phase of T. cruzi infection.
我们之前已经表明，来自年轻而非老龄BALB/c小鼠的脾脏γδT细胞在克氏锥虫感染急性期的体内和体外均具有抑制活性。本研究旨在调查来自克氏锥虫感染的正常胸腺或无胸腺小鼠的γδT细胞的抑制活性，以及胸腺在感染急性期调节非黏附性脾细胞抑制活性中的作用。用全脾细胞重建或未重建的老龄或无胸腺BALB/c小鼠的脾脏γδT细胞，在加入完全异基因混合淋巴细胞培养物时未表现出抑制活性。相比之下，来自年轻正常胸腺BALB/c小鼠的脾脏γδT细胞在体外表现出抑制活性。克氏锥虫攻击后，胸腺切除术以时间依赖性方式降低了年轻BALB/c小鼠的脾脏γδT细胞抑制活性。持续向老龄小鼠、年轻胸腺切除小鼠或全脾细胞重建的无胸腺小鼠提供胸腺细胞可重新建立γδT细胞抑制活性。特别重要的是观察到，在克氏锥虫感染急性期γδT细胞的耗竭恢复了这些小鼠对诸如卵清蛋白等无关抗原产生体液免疫反应的能力。这些结果表明，胸腺外起源的γδT细胞不能介导抑制作用，并且胸腺在克氏锥虫感染急性期的抑制调节中发挥作用。
