2020 年 26 巻 6 号 p. 847-854
The number of patients suffering from type I hypersensitivity, including hay fever and food allergies, is increasing. Recent studies have focused on food factors with fewer side effects. Previous studies have suggested that polysaccharides from seaweed suppress type I hypersensitivity by intraperitoneal administration. The aim of this study was to evaluate the inhibitory effect of polysaccharides extracted from dietary Pyropia yezoensis f. narawaensis (PPY) on type I hypersensitivity. Oral administration of PPY inhibited ear edema in the passive cutaneous anaphylaxis (PCA) reaction, but failed to have any effect when injected intraperitoneally. Oral administration of PPY for 4 days significantly increased interleukin (IL)-10 levels in serum as compared with the control group. Moreover, the inhibitory effect of PPY on ear edema was cancelled out by intravenous injection of anti-IL-10 antibody. On the other hand, it was demonstrated that PPY did not suppress β-hexosaminidase release in either a RBL-2H3 cell mono-culture or a Caco-2/RBL2H3 co-culture system, indicating that PPY does not inhibit RBL-2H3 degranulation either directly or through intestinal epithelial cells. In conclusion, dietary PPY could exert anti-allergic effects through the induction of IL-10 secretion in blood, suggesting that red algae may be effective in ameliorating type I hypersensitivity.
