Activation of regulatory T cells by oral inhabitant bacteria and relationship of their existence and growth of cancer

口腔链球菌、变形链球菌和戈登链球菌野生型(WT)和脂蛋白缺陷型(DLP)均能促进CD4+CD25+Foxp3+调节性T细胞的增殖，但抑制活性降低。Gordonii WT株对C57BL/6小鼠B16黑色素瘤生长有抑制作用，而DLP株对B16黑色素瘤生长无抑制作用，提示脂蛋白的存在在抗肿瘤活性中起重要作用。此外，还发现NK细胞而不是细胞溶解T细胞参与了抗肿瘤活性。

Both wild-type (WT) and lipoprotein-deficient (dLP) strains of oral streptococci, S. mutans and S. gordonii, increased the proliferation of CD4+CD25+Foxp3+ regulatory T cells, but reduced their suppressive activity. However, the presence of lipoprotein was not involved in these activities.WT strain of S. gordonii suppressed the growth of B16 melanoma in C57BL/6 mice, whereas dLP strain did not, suggesting that the presence of lipoprotein plays an important role in the anti-tumor activity. In addition, it was found that NK cells, but not cytolytic T cells, were involved in the anti-tumor acitivity.