Otani H, Hata I
Laboratory of Applied Biochemistry of Animal Products, Faculty of Agriculture, Shinshu University, Minamiminowa-mura, Japan.
J Dairy Res. 1995 May;62(2):339-48. doi: 10.1017/s0022029900031034.
The modulating effect of bovine milk casein components and their digests on the proliferative responses of mouse spleen lymphocytes and rabbit Peyer's patch cells induced or not induced by mitogens has been studied with a colorimetric assay using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide. All the casein components and their digests tested had little mitogenic effect on the proliferative responses of mouse spleen lymphocytes and rabbit Peyer's patch cells. Intact kappa-casein significantly inhibited the proliferative responses of mouse spleen lymphocytes and Peyer's patch cells induced by mitogens such as lipopolysaccharide from Salmonella typhimurium, concanavalin A, phytohaemagglutinin and pokeweed mitogen. In contrast, intact alpha s1-casein and beta-casein had little effect. kappa-Casein had an inhibitory effect after digestion by pancreatin or trypsin, but not after pepsin or chymotrypsin digestion. Both pancreatin and trypsin digests of alpha s1-casein and beta-casein significantly inhibited the proliferative responses of mouse spleen lymphocytes and rabbit Peyer's patch cells induced by mitogens, whereas pepsin and chymotrypsin digests of both caseins were without effect. Moreover, the trypsin digest of each casein component had an inhibitory effect on mouse spleen lymphocyte proliferation in the absence of mitogen. Since trypsin is a major proteinase in pancreatin, the substrate specificity of trypsin seems to be important for the formation of the inhibitory peptides from casein components. These observations suggest that intact kappa-casein and some peptides formed from milk casein components by the action of trypsin may suppress the immune responsiveness of neonates.
采用3-(4,5-二甲基噻唑-2-基)-2,5-二苯基四氮唑溴盐比色法，研究了牛乳酪蛋白成分及其消化产物对有丝分裂原诱导或未诱导的小鼠脾淋巴细胞和兔派伊尔结细胞增殖反应的调节作用。所有测试的酪蛋白成分及其消化产物对小鼠脾淋巴细胞和兔派伊尔结细胞的增殖反应几乎没有促有丝分裂作用。完整的κ-酪蛋白显著抑制由鼠伤寒沙门氏菌脂多糖、刀豆蛋白A、植物血凝素和商陆有丝分裂原等有丝分裂原诱导的小鼠脾淋巴细胞和派伊尔结细胞的增殖反应。相比之下，完整的αs1-酪蛋白和β-酪蛋白几乎没有影响。κ-酪蛋白经胰蛋白酶或胰凝乳蛋白酶消化后具有抑制作用，但经胃蛋白酶或糜蛋白酶消化后则没有。αs1-酪蛋白和β-酪蛋白的胰蛋白酶和胰凝乳蛋白酶消化产物均显著抑制由有丝分裂原诱导的小鼠脾淋巴细胞和兔派伊尔结细胞的增殖反应，而两种酪蛋白的胃蛋白酶和糜蛋白酶消化产物则没有作用。此外，每种酪蛋白成分的胰蛋白酶消化产物在无有丝分裂原的情况下对小鼠脾淋巴细胞增殖有抑制作用。由于胰蛋白酶是胰酶中的主要蛋白酶，胰蛋白酶的底物特异性似乎对酪蛋白成分抑制性肽的形成很重要。这些观察结果表明，完整的κ-酪蛋白和一些由胰蛋白酶作用于乳酪蛋白成分形成的肽可能会抑制新生儿的免疫反应性。
