Immunoregulatory function and its mechanism of food components

为了阐明食物成分对免疫功能的影响，我们研究了它们对粒细胞中中性蛋白酶如髓质酶和组织蛋白酶G的影响，因为粒细胞中的髓质酶和组织蛋白酶都参与了生物预防反应的调节。我们发现组织蛋白酶G也通过直接作用于NK细胞来增强自然杀伤细胞（NK）的活性。小鼠日粮中添加二十二碳六烯酸使粒细胞髓蛋白活性呈剂量依赖性增加，而棕榈酸、硬脂酸等饱和脂肪酸则使粒细胞髓蛋白活性降低。这些结果表明，饮食中的脂肪酸可能影响生物活性。在小鼠饮食中添加绿茶可降低粒细胞中髓质酶和组织蛋白酶G的活性。相反，小鼠饮食中的绿茶提取物增加了粒细胞中两种蛋白酶的活性。这些结果表明，绿茶中的某些成分增加或减少了粒细胞中这些中性蛋白酶的水平，从而调节了体内的生物反应。

In order to clarify the effect of food components on immune functions, their effect on neutral proteases such as medullasin and cathepsin G in granulocytes was studied, because both medullasin and cathepsin in granulocytes were shown to be engaged in the regulation of biophylaxis. We found that cathepsin G also enhances natural killer (NK) cell activity by acting directly on NK cells. Addition of docosahexaenoic acid to the diet of mice caused the increase of medullasin activity in granulocytes dose-dependently, to the contrary, saturated fatty acids such as palmitic acid and stearic acid decreased medullasin activity in granulocytes. These results indicate that fatty acid in the diet may influence biophylactic activity. Addition of green tea leaf to the diet of mice decreased both medullasin and cathepsin G activity in granulocytes. To the contrary, green tea extract in the diet of mice increased both protease activities in granulocytes. These results indicate that certain components in green tea increase or decrease these neutral protease levels in granulocytes resulting in the regulation of biophylaxis in vivo.