STUDIES ON IMMUNOREGULATORY MECHANISM OF FOOD COMPONENTS

我们检查了照射对淋巴细胞免疫球蛋白（Ig）产生的影响，发现它强烈地抑制了它们的Ig产生。玫瑰红的抑制作用增强，α-生育酚的抑制作用减弱。此外，我们发现饲粮中生育三烯醇的降脂和促Ig活性强于α-生育酚。我们还研究了γ-亚麻酸对膳食的影响，发现即使在高剂量的情况下，γ-亚麻酸也不会增加4系白三烯的产生。相反，它诱导免疫组织中二homo-γ-亚麻酸的积累，但其水平与前列腺素E_1产量无关。对膳食纤维的免疫调节活性，我们考察了衰老的影响。在老年大鼠中，水溶性膳食纤维的降脂和增Ig活性的表达弱于幼年大鼠。老龄大鼠和幼龄大鼠肠系膜淋巴结淋巴细胞Ig表达能力增强，但脾细胞Ig表达能力不增强。提示水溶性膳食纤维的靶组织是老年大鼠的肠道免疫系统。此外，我们考察了膳食蛋白质和脂肪的联合作用，发现大豆蛋白比酪蛋白具有更强的抑制LTB_4产生的活性，但不影响免疫细胞中花生四烯酸的水平。这些结果表明，各种食物成分对脂质代谢和免疫功能具有调节作用，并在其生物学效应的表达上相互作用。

We examined the effect of irradiation on immunoglobulin (Ig) production of lymphocytes and found that it strongly suppressed their Ig production. The suppressive effect was enhanced in the presence of Rose Bengal, but depressed in the presence of α-tocopherol. In addition, we found that dietary tocotrienols had serum lipid-decreasing and Ig production-enhancing activities stronger than α-tocopherol. We also examined the dietary effect of γ-linolenic acid and found that it did not enhance of 4-series leukotriene production even at high dose administrations. On the contrary, it induced accumulation of dihomo-γ-linolenic acid in immune tissues, but the level was not correlated with their prostaglandin E_1 productivity. On immunoregulatory activity of dietary fibers, we examined the effect of aging. In aged rats, the expression of serum lipid-decreasing and Ig production-enhancing activities of water-soluble dietary fibers were weaker than those observed in young rats. Enhancement of Ig productivity in mesenteric lymph node lymphocytes was observed in aged rats as well as young rats, but not in splenocytes. This suggests that the target tissue of water-soluble dietary fibers is gut immune system in aged rats. In addition, we examined the combinational effect of dietary proteins and fats, and found that soy protein exerted stronger LTB_4 production-inhibiting activity than casein without affecting the level of arachidonic acid in immune cells. These results suggest that various food components exert regulatory activities on lipid metabolism and immune functions, and interact each other on the expression of their biological effect.