Ma Y, Hayglass K T, Becker A B, Halayko A J, Basu S, Simons F E R, Peng Z
Department of Pediatrics and Child Health, University of Manitoba, Winnipeg, Manitoba, Canada.
Allergy. 2007 Jun;62(6):675-82. doi: 10.1111/j.1398-9995.2007.01384.x.
Monoclonal antibodies or soluble receptors have been used to block over-produced endogenous cytokines. However, they have disadvantages of short half-lives, high costs, and possible adverse effects. Using interleukin (IL)-4 as a model target, we sought to develop a novel therapeutic strategy by constructing an IL-4 peptide-based vaccine for blocking IL-4 on a persistent basis, and to evaluate its efficacy in a mouse model of asthma.
A peptide was selected by antigenic prediction and structure analysis of IL-4/receptor complex. The vaccine was constructed by employing truncated hepatitis B core antigen as carrier with the peptide inserted using gene engineering methods. It was then expressed, purified and identified. Prior to intraperitoneal sensitization and intranasal challenge with ovalbumin, mice were subcutaneously immunized three times with the vaccine, or the carrier or saline as controls. Serum antibodies, inflammatory cells in bronchoalveolar lavage fluids (BALF), lung histology, and responsiveness to inhaled methacholine were analyzed.
The vaccine presented as virus-like particles and reacted to polyclonal anti-IL-4 in Western blotting. Vaccinated mice produced high titers of IgG to IL-4. Serum ovalbumin-specific IgE, eosinophil accumulation in BALF, goblet cell hyperplasia, tissue inflammation and methacoline-induced respiratory responses were markedly suppressed in vaccinated mice with statistical significance, as compared with those in the control groups.
Administration of this novel IL-4 vaccine led to an overall decrease in the development of airway allergic inflammatory responses. The results indicate that cytokine peptide-based vaccines hold potential for treatment of asthma and, by extension, other diseases where over-expressed cytokines play a pivotal role in pathogenesis.
单克隆抗体或可溶性受体已被用于阻断过量产生的内源性细胞因子。然而，它们存在半衰期短、成本高以及可能产生不良反应等缺点。以白细胞介素（IL）-4为模型靶点，我们试图通过构建一种基于IL-4肽的疫苗来持续阻断IL-4，从而开发一种新的治疗策略，并在哮喘小鼠模型中评估其疗效。
通过对IL-4/受体复合物进行抗原预测和结构分析来选择一种肽。采用截短的乙肝核心抗原作为载体，利用基因工程方法将该肽插入其中构建疫苗。然后对其进行表达、纯化和鉴定。在用卵清蛋白进行腹腔致敏和鼻内激发之前，将小鼠皮下免疫该疫苗三次，或以载体或生理盐水作为对照。分析血清抗体、支气管肺泡灌洗液（BALF）中的炎性细胞、肺组织学以及对吸入乙酰甲胆碱的反应性。
该疫苗呈现为病毒样颗粒，在蛋白质印迹法中与多克隆抗IL-4发生反应。接种疫苗的小鼠产生了高滴度的针对IL-4的IgG。与对照组相比，接种疫苗的小鼠血清中卵清蛋白特异性IgE、BALF中嗜酸性粒细胞积聚、杯状细胞增生、组织炎症以及乙酰甲胆碱诱导的呼吸反应均受到明显抑制，具有统计学意义。
给予这种新型IL-4疫苗导致气道过敏性炎症反应的总体发展有所下降。结果表明，基于细胞因子肽的疫苗在治疗哮喘以及在细胞因子过度表达在发病机制中起关键作用的其他疾病方面具有潜力。
