Christophersen Asbjørn, Risnes Louise F, Bergseng Elin, Lundin Knut E A, Sollid Ludvig M, Qiao Shuo-Wang
Centre for Immune Regulation and Department of Immunology, University of Oslo and Oslo University Hospital, 0372 Oslo, Norway; and
Centre for Immune Regulation and Department of Immunology, University of Oslo and Oslo University Hospital, 0372 Oslo, Norway; and.
J Immunol. 2016 Mar 15;196(6):2819-26. doi: 10.4049/jimmunol.1501152. Epub 2016 Feb 19.
Celiac disease (CD) is an HLA-associated disorder characterized by a harmful T cell response to dietary gluten. It is not understood why most individuals who carry CD-associated HLA molecules, such as HLA-DQ2.5, do not develop CD despite continuous gluten exposure. In this study, we have used tetramers of HLA-DQ2.5 bound with immunodominant gluten epitopes to explore whether HLA-DQ2.5(+) healthy individuals mount a specific CD4(+) T cell response to gluten. We found that gluten tetramer-binding memory cells were rare in blood of healthy individuals. These cells showed lower tetramer-binding intensity and no signs of biased TCR usage compared with gluten tetramer-binding memory T cells from patients. After sorting and in vitro expansion, only 18% of the tetramer-binding memory cells from healthy subjects versus 79% in CD patients were gluten-reactive upon tetramer restaining. Further, T cell clones of tetramer-sorted memory cells of healthy individuals showed lower gluten-specific proliferative responses compared with those of CD patients, indicating that tetramer-binding memory cells in healthy control subjects may be cross-reactive T cells. In duodenal biopsy specimens of healthy control subjects, CD4(+) T cells were determined not to be gluten reactive. Finally, gluten tetramer-binding cells of healthy individuals did not coexpress regulatory T cell markers (Foxp3(+) CD25(+)) and cultured T cell clones did not express a cytokine profile that indicated immune-dampening properties. The results demonstrate that healthy HLA-DQ2.5(+) individuals do not mount a T cell response to immunodominant gluten epitopes of CD.
乳糜泻(CD)是一种与HLA相关的疾病,其特征是对膳食中的麸质产生有害的T细胞反应。目前尚不清楚为什么大多数携带与CD相关的HLA分子(如HLA-DQ2.5)的个体,尽管持续接触麸质却不会患上CD。在本研究中,我们使用与免疫显性麸质表位结合的HLA-DQ2.5四聚体,来探究HLA-DQ2.5(+)健康个体是否对麸质产生特异性CD4(+) T细胞反应。我们发现,麸质四聚体结合记忆细胞在健康个体的血液中很少见。与来自患者的麸质四聚体结合记忆T细胞相比,这些细胞显示出较低的四聚体结合强度,且没有TCR使用偏向的迹象。经过分选和体外扩增后,来自健康受试者的四聚体结合记忆细胞中只有18%在四聚体再染色时对麸质有反应,而CD患者中这一比例为79%。此外,与CD患者相比,健康个体经四聚体分选的记忆细胞的T细胞克隆显示出较低的麸质特异性增殖反应,这表明健康对照受试者中的四聚体结合记忆细胞可能是交叉反应性T细胞。在健康对照受试者的十二指肠活检标本中,确定CD4(+) T细胞对麸质无反应。最后,健康个体的麸质四聚体结合细胞不共表达调节性T细胞标志物(Foxp3(+) CD25(+)),培养的T细胞克隆也不表达表明具有免疫抑制特性的细胞因子谱。结果表明,健康的HLA-DQ2.5(+)个体不会对CD的免疫显性麸质表位产生T细胞反应。