Studies on intraepithelial lymphocytes and cytokine production in the protection against nematode infection

肠道线虫的驱虫、自愈机制近年来被认识到，针对寄生虫的直接效应细胞在不同肠道线虫种类中具有选择性。为了概括蠕虫排出的机制，我们需要了解直接效应细胞的调节机制。本研究以肠道上皮内细胞（IEL）为研究对象，利用流式细胞术和RT-PCR技术研究鼠耳绦虫（Sr）和巴西巴西菌（Nb）感染时T细胞亚群和细胞因子的产生。我们也用这些方法检查了肠系膜淋巴结细胞。sr感染和nb感染小鼠的平均IEL恢复率分别低于正常小鼠的40%和6%。在sr感染小鼠和nb感染小鼠的IEL中，CD3^+、CD4^+、CD8^+和gammadeltaTCR^+细胞的百分比基本没有差异。在第7天，sr感染小鼠的IEL中明显检测到Th2型细胞因子、IL-4和IL-3 mRNA，而在正常小鼠的IEL中未检测到。在正常IEL中检测到较多的ifn - γ mRNA，在感染后几乎没有变化。由于IL-3 mRNA（肥大细胞生长因子信使）在感染的IEL中增加，因此IEL可能在Sr的排出中起作用。我们无法检测nb感染小鼠IEL中mRNA的表达。流式细胞术检测肠系膜淋巴结细胞内细胞因子。在sr和nb感染中，肠系膜淋巴结中含有IL-3的细胞增加。含IL-4或ifn - γ的细胞在感染两种寄生虫后基本没有差异。然而，含TNF的细胞在sr和nb感染之间明显不同。含TNF的细胞百分比在sr感染中下降，而在nb感染中没有下降。这些结果可能有助于阐明不同肠道线虫种之间的选择机制。我们还研究了nb感染小鼠调节粘液分泌的机制，因为nb感染小鼠的IEL恢复较少，粘液分泌较多。我们发现杯状细胞的粘液分泌可能受CD4^+细胞的调节。少

The mechanism of worm expulsion, spontaneous cure, of the intestinalnematodes is recently understood that the direct effector cells against parasites are selective among various intestinal nematode species. To generalize the mechanism of worm expulsion, we need to understand the mechanism for regulating direct effector cells. We focused on intestinalintraepithelial cells (IEL), and tried to study on T cell subsets and cytokine production in S.ratti (Sr) and N.brasiliensis (Nb) -infection by flow cytometry and RT-PCR.We examined also on mesenteric lymph node cells by those methods. Mean recovery of IEL from Sr-infected and Nb-infected mice were less than 40% and 6% of IEL from normal mice, respectively. Percentage of CD3^+, CD4^+, CD8^+ and gammadeltaTCR^+ cells was not different basically between IEL from Sr-infected and that from Nb-infected mice. Th2 type cytokines, IL-4 and IL-3 mRNA were detected clearly in IEL from Sr-infected mice on day 7 but not in normal IEL.Th1 type cytokine, … More IFN-gamma mRNA was detected in normal IEL and hardly changed in the infection. IEL probably play a role on the expulsion of Sr, because IL-3 mRNA,a mast cell growth factor messenger, was increased in IEL in the infection. We could not examine the expression of mRNA in IEL from Nb-infected mice.Intracellularcytokines in mesenteric lymph node cells were detected by flow cytometry. IL-3 containing cells increased in the mesenteric lymph node both in Sr-and Nb-infection. IL-4 or IFN-gamma containing cells were not different basicallyamong infection with the two parasites. TNF containing cells, however, were clearly different between Sr-and Nb-infection. Percentage of TNF containing cells decreased in Sr-infection but not in Nb-infection.These results may be helpful to clarify the selective mechanism among different intestinal nematode species. We also examined mechanism of regulating mucus secretion in Nb-infected mice, because less IEL were recovered and more mucus seemed to be secreted in Nb-infection. We found that mucus secretion from goblet cells may be regulated by CD4^+ cells. Less