Martucci Susi, Fraser Jocelyn Sophie, Biagi Federico, Corazza Gino Roberto, Ciclitira Paul Jonathan, Ellis Heather Julia
Gastroenterology Department, Rayne Institute (KCL), St Thomas' Hospital, London, UK.
Eur J Gastroenterol Hepatol. 2003 Dec;15(12):1293-8. doi: 10.1097/00042737-200312000-00007.
To investigate, using an organ culture system, in-vitro toxicity of region 51-70 of A-gliadin (SQQPYLQLQPFPQPQLPYSQ), a peptide overlapping some of the sequences recently characterized as DQ2-restricted T-cell epitopes in coeliac disease.
Jejunal biopsies obtained from each of ten coeliac patients (eight treated, two untreated) and two non-coeliac patients were cultured in vitro for 18 h in the presence of A-gliadin amino acids 51-70 (200 microg/ml), organ culture medium only, peptic-tryptic digest of gliadin (1 mg/ml) or ovalbumin (1 mg/ml), the last two acting as positive and negative controls, respectively. Morphometric analysis involved measuring the cell height of 30 enterocytes, selected at random from the middle third of different villi for each section. Mean enterocyte cell heights (ECH) were compared with values for specimens cultured in medium alone. Levels of tissue transglutaminase antibody in biopsy supernatants were assessed by enzyme-linked immunosorbent assay (ELISA).
In eight of ten coeliac patients, A-gliadin 51-70 was significantly toxic, causing a 30% decrease in ECH when compared with medium alone. In two of ten subjects, the peptide did not show any toxic effect. In all ten cases, we found that both positive and negative controls worked as expected. The peptide was non-toxic in the non-coeliac individuals. Tissue transglutaminase antibody titre in the supernatant was not found to be related to mucosal damage.
We showed that the peptide corresponding to amino acids 51-70 of A-gliadin is characterized by in-vitro toxicity to the jejunal coeliac mucosa, correlating with recent findings of an immunological role of similar peptides. The lack of response in two of ten subjects suggests that this epitope may not be relevant in all cases of coeliac disease.
利用器官培养系统研究麦醇溶蛋白A的51 - 70区域（SQQPYLQLQPFPQPQLPYSQ）的体外毒性，该肽段与近期在乳糜泻中被鉴定为DQ2限制性T细胞表位的部分序列重叠。
从10例乳糜泻患者（8例经过治疗，2例未治疗）和2例非乳糜泻患者获取空肠活检组织，在含麦醇溶蛋白A的51 - 70氨基酸（200微克/毫升）、仅含器官培养基、麦醇溶蛋白的胃蛋白酶 - 胰蛋白酶消化物（1毫克/毫升）或卵清蛋白（1毫克/毫升）的条件下体外培养18小时，后两者分别作为阳性和阴性对照。形态计量分析包括测量从每个切片不同绒毛中部三分之一处随机选取的30个肠上皮细胞的细胞高度。将平均肠上皮细胞高度（ECH）与单独在培养基中培养的标本的值进行比较。通过酶联免疫吸附测定（ELISA）评估活检上清液中组织转谷氨酰胺酶抗体的水平。
在10例乳糜泻患者中的8例，麦醇溶蛋白A的51 - 70具有显著毒性，与单独培养基相比，ECH降低了30%。在10例受试者中的2例，该肽未显示任何毒性作用。在所有10例病例中，我们发现阳性和阴性对照均按预期发挥作用。该肽在非乳糜泻个体中无毒。未发现上清液中组织转谷氨酰胺酶抗体滴度与黏膜损伤有关。
我们表明，对应于麦醇溶蛋白A的51 - 70氨基酸的肽段对空肠乳糜泻黏膜具有体外毒性，这与近期关于类似肽段免疫作用的研究结果相关。10例受试者中有2例无反应，提示该表位可能并非在所有乳糜泻病例中都起作用。
