Cetkovic-Cvrlje M, Gerling I C, Muir A, Atkinson M A, Elliott J F, Leiter E H
The Jackson Laboratory, Bar Harbor, Maine 04609, USA.
Diabetes. 1997 Dec;46(12):1975-82. doi: 10.2337/diab.46.12.1975.
A single injection of syngeneic islet cells into the thymus of 4-week-old NOD/Lt female mice strongly retards diabetogenesis. The present study used the intrathymic route of antigen administration to compare the relative efficacy of peptides/proteins derived from two major candidate pancreatic beta-cell autoantigens, insulin and GAD65, to modulate diabetogenesis. Intrathymic administration of insulin B chain or recombinant human GAD65 significantly suppressed diabetogenesis during a 20-week follow-up period, whereas no protection was mediated by either insulin A chain or a synthetic peptide (A2) derived from it. Quite unexpectedly, two GAD65-derived peptides near the COOH-terminus (p34 and p35) accelerated diabetes onset. Semiquantitative reverse transcription-polymerase chain reaction analysis was performed on cDNAs from isolated islets or whole pancreases of NOD/Lt females 4 weeks after intrathymic injections. Protection mediated by intrathymic administration with either intact islet cells or GAD65 were correlated with an upregulation of mRNA for T-helper 2 (Th2)-associated cytokines (interleukin [IL]-4, IL-10), concomitant with downregulation of Th1-associated interferon (IFN) transcripts (all normalized to T-cell receptor Cbeta transcripts) in islet-infiltrating lymphocytes. Protection mediated by the intrathymic administration of insulin B chain, however, correlated only with a modest upregulation of IL-4 and IL-10 transcript levels, and no diminution in IFN-gamma transcripts. In contrast, the diabetes-accelerating GAD65 p34 and p35 peptides were not associated with an immune deviation, expressing levels of IFN-gamma characteristic of islet-infiltrating lymphocytes in vehicle-injected NOD controls. Hence, Th1-to-Th2 immune deviation provides only a partial explanation for peptide immunotherapy of diabetes in NOD mice. The finding that certain peptides can accelerate rather than retard diabetogenesis as a function of route and age of administration adds a cautionary note to this type of therapy.
将同基因胰岛细胞单次注射到4周龄NOD/Lt雌性小鼠的胸腺中可显著延缓糖尿病的发生。本研究采用胸腺内抗原给药途径，比较了两种主要的候选胰岛β细胞自身抗原胰岛素和GAD65衍生的肽/蛋白调节糖尿病发生的相对效力。在20周的随访期内，胸腺内注射胰岛素B链或重组人GAD65可显著抑制糖尿病的发生，而胰岛素A链或其衍生的合成肽（A2）则无保护作用。非常出乎意料的是，GAD65羧基末端附近的两种肽（p34和p35）加速了糖尿病的发病。在胸腺内注射4周后，对NOD/Lt雌性小鼠分离的胰岛或整个胰腺的cDNA进行了半定量逆转录-聚合酶链反应分析。胸腺内注射完整胰岛细胞或GAD65介导的保护作用与辅助性T细胞2（Th2）相关细胞因子（白细胞介素[IL]-4、IL-10）的mRNA上调相关，同时胰岛浸润淋巴细胞中Th1相关干扰素（IFN）转录本下调（均以T细胞受体Cβ转录本为标准进行标准化）。然而，胸腺内注射胰岛素B链介导的保护作用仅与IL-4和IL-10转录水平适度上调相关，而IFN-γ转录本无减少。相反，加速糖尿病的GAD65 p34和p35肽与免疫偏移无关，其IFN-γ表达水平与注射溶媒的NOD对照小鼠胰岛浸润淋巴细胞的特征一致。因此，Th1向Th2的免疫偏移只是NOD小鼠糖尿病肽免疫治疗的部分解释。某些肽可根据给药途径和年龄加速而非延缓糖尿病发生的这一发现为这类治疗敲响了警钟。
