Yoshida Tadashi, Hirano Aki, Wada Hanae, Takahashi Koji, Hattori Makoto
Department of Applied Biological Science, Tokyo University of Agriculture and Technology, Tokyo, Japan.
Int Arch Allergy Immunol. 2004 Mar;133(3):239-47. doi: 10.1159/000076830. Epub 2004 Feb 16.
Since allergen-specific IgE is directly involved in the type I allergic reaction, development of a method for inhibiting Th2 responses which lead to the induction of IgE production would be a useful approach for preventing allergic disorders. The ability and mechanism of alginic acid oligosaccharide (ALGO), an oligosaccharide obtained from natural edible polysaccharide, for suppressing Th2 responses was examined in detail.
Lymph node cells obtained from beta-lactoglobulin (beta-LG)-primed BALB/c mice were cultured in vitro with an antigen for 3 days in the absence or presence of ALGO. The amount of cytokine in each culture supernatant was measured. The effect of ALGO on Th2 development was also examined by using ovalbumin specific T cell receptor transgenic mice. Antibody production in the serum of BALB/c mice that had been immunized with beta-LG or beta-LG plus ALGO was investigated.
The production of IFN-gamma induced by antigen stimulation was upregulated by ALGO in a dose-dependent manner. IL-12 production was also enhanced by ALGO, and the addition of the anti-IL-12 antibody to the culture abrogated the effect of ALGO. On the other hand, IL-4 production by antigen-stimulated splenocytes of transgenic mice was suppressed in the presence of ALGO. Furthermore, IgE production by ALGO-treated mice was significantly inhibited compared with control mice.
These results indicate that ALGO suppressed antigen-induced Th2 development by inducing IL-12 production. ALGO also inhibited in vivo IgE production. These findings suggest that ALGO is expected to be an edible anti-allergic agent.
由于变应原特异性IgE直接参与I型过敏反应，开发一种抑制导致IgE产生的Th2反应的方法将是预防过敏性疾病的一种有用方法。详细研究了从天然可食用多糖中获得的低聚糖海藻酸寡糖（ALGO）抑制Th2反应的能力和机制。
从经β-乳球蛋白（β-LG）致敏的BALB/c小鼠获得的淋巴结细胞，在有或无ALGO的情况下，与抗原在体外培养3天。测量每种培养上清液中细胞因子的量。还使用卵清蛋白特异性T细胞受体转基因小鼠研究了ALGO对Th2发育的影响。研究了用β-LG或β-LG加ALGO免疫的BALB/c小鼠血清中的抗体产生情况。
ALGO以剂量依赖性方式上调抗原刺激诱导的IFN-γ产生。ALGO也增强了IL-12的产生，并且向培养物中添加抗IL-12抗体消除了ALGO的作用。另一方面，在存在ALGO的情况下，转基因小鼠抗原刺激的脾细胞产生的IL-4受到抑制。此外，与对照小鼠相比，经ALGO处理的小鼠的IgE产生受到显著抑制。
这些结果表明，ALGO通过诱导IL-12产生来抑制抗原诱导的Th2发育。ALGO还抑制体内IgE的产生。这些发现表明，ALGO有望成为一种可食用的抗过敏剂。
