Yagi T, Sato A, Hayakawa H, Ide K
Second Department of Internal Medicine, Hamamatsu University School of Medicine, Japan.
J Allergy Clin Immunol. 1997 Jan;99(1 Pt 1):38-47. doi: 10.1016/s0091-6749(97)70298-7.
To investigate the effect of aging on the allergic airway response, we examined the bronchoconstrictive responses and cellular inflammatory changes in a rat model of bronchial asthma by evaluating young and old animals. Two different age groups of Brown-Norway rats, actively sensitized by injection of ovalbumin into the foot pads, were used: 7 to 8 weeks old (young group) and 100 to 120 weeks old (aged group). Both the aged and young rats produced on ovalbumin-specific IgE antibody and exhibited an immediate asthmatic response after exposure to ovalbumin, but the degree of specific IgE antibody was significantly higher in young rats. The young group showed a marked increase in the number of eosinophils and neutrophils in bronchoalveolar lavage fluid 2 days after exposure to ovalbumin, whereas no eosinophilia was seen in the aged group. To evaluate the mechanism of the decreased accumulation of eosinophils in aged rats, cells from popliteal lymph nodes from ovalbumin-sensitized rats were incubated with ovalbumin for 48 hours. Although eosinophil chemotactic activity, determined by a modified Boyden chamber method, was present in the supernatant of cultured lymph node cells from young rats, it was absent from those of aged rats. In vivo administration of anti-IL-5 monoclonal antibody revealed that one of the factors of eosinophil chemotactic activity was IL-5. Lymph node cells from aged rats tended to produce greater amounts of interferon-gamma than did those from young animals. Findings indicate that aged rats have a defect in eosinophil accumulation in sites exposed to antigen, probably because of an age-dependent alteration in T cells.
为研究衰老对过敏性气道反应的影响，我们通过评估年轻和老年动物，检测了支气管哮喘大鼠模型中的支气管收缩反应和细胞炎症变化。使用了两组不同年龄的经足垫注射卵清蛋白主动致敏的Brown-Norway大鼠：7至8周龄（年轻组）和100至120周龄（老年组）。老年和年轻大鼠均产生了卵清蛋白特异性IgE抗体，并在接触卵清蛋白后表现出即刻哮喘反应，但年轻大鼠的特异性IgE抗体水平显著更高。年轻组在接触卵清蛋白2天后，支气管肺泡灌洗液中的嗜酸性粒细胞和中性粒细胞数量显著增加，而老年组未见嗜酸性粒细胞增多。为评估老年大鼠嗜酸性粒细胞积聚减少的机制，将来自卵清蛋白致敏大鼠腘窝淋巴结的细胞与卵清蛋白孵育48小时。尽管通过改良的Boyden小室法测定，年轻大鼠培养的淋巴结细胞上清液中存在嗜酸性粒细胞趋化活性，但老年大鼠的上清液中未检测到。体内给予抗IL-5单克隆抗体表明，嗜酸性粒细胞趋化活性的因素之一是IL-5。老年大鼠的淋巴结细胞比年轻动物的淋巴结细胞倾向于产生更多的干扰素-γ。研究结果表明，老年大鼠在抗原暴露部位的嗜酸性粒细胞积聚存在缺陷，这可能是由于T细胞的年龄依赖性改变所致。
