Development of non-allergic peptide preparation having mucosal immunostimulatory ability

本研究结果如下：1)饲粮酪蛋白磷脂肽通过提高黏膜IgA水平和降低血清过敏原特异性IgE水平来减轻NC小鼠的特应性皮炎。2)证实酪蛋白磷酸化肽的免疫调节活性与SerP-X-SerP序列有关。3) SerP-SerP-SerP与酪蛋白磷酸肽富含磷酸丝氨酸区特异性抗体反应明显，而SerP-Leu-SeP则无反应。提示SerP-X-SerP （X不是SerP）为非过敏性iga刺激肽。4)用14种允许作为食品添加剂的蛋白酶对牛酪蛋白进行消化，回收酪蛋白磷酸肽。由米曲霉蛋白酶消化的酪蛋白制备的酪蛋白磷酸化肽对IgA的产生有较高的刺激作用，与酪蛋白磷酸化肽中富含磷酸丝氨酸区域的抗体反应性较弱。这些事实表明，由米曲霉蛋白酶消化的酪蛋白制备的酪蛋白磷酸肽是一种非过敏性的促iga肽。5)一般来说，由15到16个葡萄糖组成的糊精被认为是不过敏的。另一方面，两个磷酸基团是酪蛋白磷酸化肽显示促iga作用所必需的。因此，制备了与5 ~ 7个磷酸基团共价偶联的糊精。磷酸化糊精可刺激小鼠脾细胞产生IgA。此外，给小鼠口服含有磷酸化糊精的饮食35 d后，肠道对致病菌的IgA水平显著升高。这些结果表明，磷酸化糊精是另一种非化感lga刺激物质。

Results obtained in the present investigation were summarized as follows:1) Dietary casein phosphopeptides reduced atopic dermatitis in NC mice via the enhancement of mucosal IgA levels and the reduction of serum IgE levels specific to allergens.2) The immunoregulatory activity of casen phosphopeptides was confirmed to be attributable to the sequence SerP-X-SerP.3) SerP-SerP-SerP obviously reacted with an antibody specific to phosphoserine-rich region of casein phosphopeptides whereas SerP-Leu-SeP was inert. These results suggested that SerP-X-SerP (X is not SerP) was non-allergic IgA-stimulatory peptide.4) Bovine casein was digested with 14 kinds of proteases, which are permitted to use as food supplements, and casein phosphopeptides were recovered from the digests. Casein phosphopeptides preparation obtained from caseins digested with proteases from Aspergillus oryzae had high stimulatory effect on IgA production and little reactivity with the antibody specific to phosphoserine-rich region of casein phosphopeptides. These facts suggested that the casein phosphopeptide preparation obtained from caseins digested with proteases from Aspergillus oryzae was non-allergic IgA-stimulatory peptide.5) In general, a dextrin consisting of 15 to 16 glucoses is considered to be non-allergic. On the other hand two phosphate groups is essential to display IgA-stimulatory effect of casein phosphopeptides. Hence, dextrins covalently coupled with 5 to 7 phosphate groups were prepared. The phosphorylated dextrin sitmulated IgA production in mouse spleen cell cultures. Moreover, the intestinal IgA level to pathogenic bacteria orally ingested was increased significantly when mice were given a diet containing phosphorylated dextrin for 35 days. These results suggest that phosphorylated dextrin is another non-allereic lgA-stimulatorv substance.