Baker Caroline, Petrich de Marquesini Liliana G, Bishop Amanda J, Hedges Alan J, Dayan Colin M, Wong F Susan
Department of Cellular and Molecular Medicine, School of Medical Sciences, University of Bristol, University Walk, Bristol BS8 1TD, UK.
J Clin Immunol. 2008 Jul;28(4):350-60. doi: 10.1007/s10875-008-9177-4. Epub 2008 Feb 29.
In this study, we explored the breadth of CD8 T cell reactivity to preproinsulin (PPI) in type 1 diabetes.
We tested a complete peptide set in pools covering all 406 potential 8-11mer epitopes of PPI and 61 algorithm-predicted human leukocyte antigen (HLA)-A2-specific epitopes (15 pools) from islet-specific glucose-6-phophatase catalytic subunit-related protein (IGRP), using a CD8-specific granzyme B enzyme-linked immunosorbent spot assay.
Responses were seen to 64 of the 102 PPI pools in two or more newly diagnosed patients (63%) compared to 11 pools in the control subjects (11%, p < 0.0001, Fisher's exact test). We identified five pools containing 20 peptides, which distinguished patients from control subjects, most of which had predicted low-affinity binding to HLA class I molecules. In contrast, fewer (5 of 15 = 33%) IGRP peptide pools, selected by higher binding affinity for HLA-A2 (present in seven of eight patients and five of seven control subjects), stimulated responses in two or more patients, and none stimulated responses in more than two control subjects (p = 0.042, Fisher's exact test).
Thus, we conclude that CD8 T cell reactivity to PPI in patients with type 1 diabetes can be much broader than shown previously and more diverse than seen in control subjects. Furthermore, responses were often stimulated by peptides with low predicted HLA-binding affinities.
在本研究中，我们探究了1型糖尿病患者中CD8 T细胞对胰岛素原（PPI）反应的广度。
我们使用CD8特异性颗粒酶B酶联免疫斑点试验，对覆盖PPI所有406个潜在8 - 11聚体表位的完整肽池以及来自胰岛特异性葡萄糖-6-磷酸酶催化亚基相关蛋白（IGRP）的61个经算法预测的人类白细胞抗原（HLA）-A2特异性表位（15个肽池）进行了检测。
在两名或更多新诊断患者中，102个PPI肽池中64个出现反应（63%），而在对照受试者中为11个肽池（11%，p < 0.0001，Fisher精确检验）。我们鉴定出五个包含20种肽的肽池，它们可区分患者与对照受试者，其中大多数对HLA I类分子的预测结合亲和力较低。相比之下，通过对HLA - A2具有更高结合亲和力而选择的IGRP肽池较少（15个中的5个 = 33%）刺激两名或更多患者出现反应，且没有一个肽池在超过两名对照受试者中刺激反应（p = 0.042，Fisher精确检验），HLA - A2在八名患者中的七名以及七名对照受试者中的五名中存在。
因此，我们得出结论，1型糖尿病患者中CD8 T细胞对PPI的反应性可能比先前显示的要广泛得多，并且比对照受试者中观察到的更多样化。此外，反应通常由预测HLA结合亲和力低的肽刺激产生。
