Maeda Akiko, Maeda Tadao, Liang Yan, Yenerel Melda, Saperstein David A
Department of Ophthalmology, University of Washington, Seattle, WA 98195-6485, USA.
Mol Vis. 2006 Aug 10;12:885-91.
To assess the cytotoxic T lymphocyte antigen 4 (CTLA4) pathway in the recoverin peptide (R64; AYAQHVFRSF) mouse model of cancer-associated retinopathy (CAR) and to assess the protective effects of subconjunctival triamcinalone injections in this model.
To study the role of the CTLA4 pathway on the R64-induced mouse model of CAR, BALB/c mice were immunized with R64. The mice were further intraperitoneally treated with anti-CTLA4 antibody to get stronger immunoreaction. The development of CAR was evaluated by electroretinogram (ERG) examinations 21 days after treatment. A cytotoxicity assay was employed to detect induction of R64-specific cytotoxic T lymphocytes (CTLs). Immunoblotting to assess the development of anti-recoverin antibody and a T cell proliferation assay to determine the activity of lymphocytes against R64 were examined in two experimental groups, anti-CTLA4 antibody treated and untreated mice.To study the protective effect of subconjunctival triamcinalone in this model, mice immunized with R64 peptide and anti-CTLA4 antibody were either treated with 50 mg/kg/body weight of triamcinalone or phosphate buffered saline (PBS). These mice were assayed using ERG and histological examination 35 days after the first R64 immunization.
When mice were challenged with R64 peptide and anti-CTLA4 antibody, R64 peptide-specific CTLs were induced and decreased b-wave amplitudes were observed in ERG. Conversely, no CAR symptoms were detected in mice not treated with anti-CTLA4 antibody. Anti-CTLA4 antibody treatment did not give any significant differences in T cell proliferation and humoral reaction against recoverin. Subconjunctival triamcinalone treated mice show a trend toward improved survival of outer nuclear layer cell bodies, but did not show significant improvement of ERG amplitudes compared to the untreated mice.
Inhibition of the CTLA4 pathway is essential for the development of recoverin-induced murine CAR, suggesting that strengthening negative T cell signaling through CTLA4 may lessen the retinal degenerations in CAR-affected subjects. The positive effects of attenuation of the CTLA4 pathway must be weighed against a potential negative effect on survival since this pathway may also provide natural immunotherapy against the underlying malignancy. Subconjunctival injections of triamcinalone may have beneficial effects on the integrity of the outer nuclear layer (ONL) of the retina in the CAR model, although there was no significant effect on the ERG recordings.
评估癌症相关性视网膜病变（CAR）恢复蛋白肽（R64；AYAQHVFRSF）小鼠模型中的细胞毒性T淋巴细胞抗原4（CTLA4）通路，并评估结膜下注射曲安奈德在该模型中的保护作用。
为研究CTLA4通路在R64诱导的CAR小鼠模型中的作用，用R64免疫BALB/c小鼠。进一步给小鼠腹腔注射抗CTLA4抗体以增强免疫反应。在治疗21天后通过视网膜电图（ERG）检查评估CAR的发展。采用细胞毒性试验检测R64特异性细胞毒性T淋巴细胞（CTL）的诱导情况。在抗CTLA4抗体处理组和未处理组两个实验组中，通过免疫印迹评估抗恢复蛋白抗体的产生情况，并通过T细胞增殖试验确定淋巴细胞对R64的活性。为研究结膜下注射曲安奈德在该模型中的保护作用，用R64肽和抗CTLA4抗体免疫的小鼠分别用50mg/kg体重的曲安奈德或磷酸盐缓冲盐水（PBS）处理。在首次R64免疫35天后，对这些小鼠进行ERG检测和组织学检查。
当用R64肽和抗CTLA4抗体攻击小鼠时，诱导产生了R64肽特异性CTL，并且在ERG中观察到b波振幅降低。相反，未用抗CTLA4抗体处理的小鼠未检测到CAR症状。抗CTLA4抗体处理在T细胞增殖和针对恢复蛋白的体液反应方面未产生任何显著差异。结膜下注射曲安奈德处理的小鼠显示出外层核层细胞体存活率提高的趋势，但与未处理的小鼠相比，ERG振幅未显示出显著改善。
抑制CTLA4通路对于恢复蛋白诱导的小鼠CAR的发展至关重要，这表明通过CTLA4加强负性T细胞信号传导可能减轻CAR患者的视网膜变性。由于该通路也可能提供针对潜在恶性肿瘤的天然免疫疗法，因此必须权衡CTLA4通路减弱的积极作用与对生存的潜在负面影响。结膜下注射曲安奈德可能对CAR模型中视网膜外层核层（ONL）的完整性有有益作用，尽管对ERG记录没有显著影响。
