Shlomai A, Trop S, Gotsman I, Jurim O, Diment J, Alper R, Rabbani E, Engelhardt D, Ilan Y
Liver Unit, Department of Medicine, Hadassah University Hospital, Jerusalem, Israel.
J Pathol. 2001 Nov;195(4):498-507. doi: 10.1002/path.974.
The imbalance between Th1 pro-inflammatory and Th2 anti-inflammatory cytokine-producing cells plays a major role in the pathogenesis of inflammatory bowel disease (IBD). Induction of oral tolerance to colitis-extracted proteins was previously shown to down-regulate the anti-colon immune response, thereby alleviating experimental colitis. Immune bystander effect and liver-associated lymphocytes expressing the NK1.1 marker (NK1.1(+) LAL) have been suggested as being important in tolerance induction. The aims of the present study were to determine whether oral administration of inflammatory and non-inflammatory colon-extracted proteins of different species can induce peripheral immune tolerance and alleviate experimental colitis; and to examine the role of NK1.1(+) LAL in oral tolerance induction. Colitis was induced in C57/B6 mice by intracolonic instillation of trinitrobenzene sulphonic acid (TNBS). Mice received six oral doses of colonic proteins extracted from TNBS-colitis colonic wall, or normal colonic wall, from four different species. Standard clinical, macroscopic, and microscopic scores were used for colitis assessment. Serum interferon gamma (IFNgamma) and interleukin 10 (IL10) levels were measured by ELISA. To evaluate the role of NK1.1(+) LAL in maintaining the balance between immunogenic and tolerogenic subsets of cells, their cytotoxicity functions were tested in tolerized and non-tolerized-mice. The administration of mouse-derived colitis-extracted proteins, or of surrogate proteins extracted from normal mouse colon, or from rat or human inflammatory colons, was found to alleviate experimental colitis. Tolerized mice had less diarrhoea; showed a marked reduction of colonic ulceration, intestinal and peritoneal adhesions, wall thickness, and oedema; and demonstrated a significant improvement of all microscopic parameters for colitis. Induction of tolerance led to an increase in IL10 and a decrease in IFNgamma serum levels. NK1.1(+) LAL cytotoxicity function increased markedly in tolerized mice. In contrast, mice fed with proteins extracted from normal rat, rabbit, and human colon, or from rabbit inflammatory colon, developed severe colitis, with a marked increase in IFNgamma and a decrease in IL10 serum levels, and down-regulation of NK1.1(+) LAL function. This study has shown that oral tolerance can be induced in experimental colitis by means of the feeding of surrogate antigens; this alleviates experimental colitis. NK1.1(+) LAL cytotoxicity function is associated with peripheral tolerance induction and may help to maintain the Th1/Th2 immune balance.
辅助性T细胞1（Th1）促炎细胞与辅助性T细胞2（Th2）抗炎细胞因子产生细胞之间的失衡在炎症性肠病（IBD）发病机制中起主要作用。先前研究表明，诱导对结肠炎提取蛋白的口服耐受可下调抗结肠免疫反应，从而缓解实验性结肠炎。免疫旁观者效应以及表达NK1.1标志物的肝脏相关淋巴细胞（NK1.1(+) LAL）被认为在耐受诱导中起重要作用。本研究的目的是确定口服不同物种的炎症性和非炎症性结肠提取蛋白是否能诱导外周免疫耐受并缓解实验性结肠炎；并研究NK1.1(+) LAL在口服耐受诱导中的作用。通过向C57/B6小鼠结肠内灌注三硝基苯磺酸（TNBS）诱导结肠炎。小鼠接受六次口服剂量的从TNBS结肠炎结肠壁或正常结肠壁提取的结肠蛋白，这些结肠壁来自四个不同物种。使用标准临床、宏观和微观评分评估结肠炎。通过酶联免疫吸附测定（ELISA）测量血清干扰素γ（IFNγ）和白细胞介素10（IL10）水平。为评估NK1.1(+) LAL在维持免疫原性和耐受性细胞亚群平衡中的作用，在耐受和未耐受小鼠中测试它们的细胞毒性功能。发现给予小鼠来源的结肠炎提取蛋白、从正常小鼠结肠或大鼠或人类炎症性结肠提取的替代蛋白可缓解实验性结肠炎。耐受小鼠腹泻较少；结肠溃疡、肠粘连和腹膜粘连、肠壁厚度及水肿明显减轻；并且结肠炎的所有微观参数均有显著改善。耐受诱导导致IL10增加和IFNγ血清水平降低。在耐受小鼠中，NK1.1(+) LAL细胞毒性功能显著增强。相反，喂食从正常大鼠、兔和人类结肠或兔炎症性结肠提取的蛋白的小鼠发生严重结肠炎，IFNγ显著增加，IL10血清水平降低，且NK1.1(+) LAL功能下调。本研究表明，通过喂食替代抗原可在实验性结肠炎中诱导口服耐受；这可缓解实验性结肠炎。NK1.1(+) LAL细胞毒性功能与外周耐受诱导相关，并可能有助于维持Th1/Th2免疫平衡。
