Kimoto Hiromi, Mizumachi Koko, Okamoto Takashi, Kurisaki Jun-Ichi
Department of Animal Products, National Institute of Livestock and Grassland Science, Ibaraki, Japan.
Microbiol Immunol. 2004;48(2):75-82. doi: 10.1111/j.1348-0421.2004.tb03490.x.
Few studies exist dealing with the probiotic activity of lactococci, which are commonly used as starter bacteria in the manufacture of many kinds of fermented dairy products. Fifteen strains of the genus Lactococcus were examined for their probiotic activities, such as immunomodulatory effects. Six strains induced the production of cytokines (IL-12, IL-6, and TNF-alpha) in macrophage-like cell line J774.1, and the highest induction was observed with Lactococcus lactis subsp. lactis G50. The cytokine induction in the J774.1 cell line was almost entirely sustained after heat-killing of the strain. Spleen cells from BALB/c mice fed G50 culture produced more IL-12 and IFN-gamma and slightly less IL-4 and IL-6 than the control (i.e., without strain G50), indicating that strain G50 can enhance Th1-type immune response in vivo. The effect of the oral administration of strain G50 on antibody response in mice was also investigated. Mice were immunized with ovomucoid (OVM), a potent egg allergen, and the antibody level in the serum was then determined. The total IgE antibody level in the group treated with strain G50 was significantly lower than that of the control. The response of OVM-specific IgG1 and IgE antibodies tended to be low in the group that was administered strain G50, compared with the response of the control group. These results suggest that strain G50 has an ability to suppress the Th2 response. Thus, Lactococcus lactis subsp. lactis G50 is a potential probiotic strain for the suppression of hypersensitive reactions caused by the Th2 response.
关于乳酸乳球菌益生菌活性的研究较少，乳酸乳球菌是多种发酵乳制品生产中常用的发酵起始菌。对15株乳酸乳球菌属菌株的益生菌活性进行了检测，如免疫调节作用。有6株菌株可诱导巨噬细胞样细胞系J774.1产生细胞因子（IL-12、IL-6和TNF-α），其中乳酸乳球菌乳酸亚种G50诱导作用最强。对该菌株进行热灭活后，J774.1细胞系中的细胞因子诱导作用几乎完全得以维持。与对照组（即未添加G50菌株）相比，喂食G50培养物的BALB/c小鼠脾细胞产生更多的IL-12和IFN-γ，而IL-4和IL-6略少，这表明G50菌株可在体内增强Th1型免疫反应。还研究了口服G50菌株对小鼠抗体反应的影响。用强效鸡蛋过敏原卵类粘蛋白（OVM）对小鼠进行免疫，然后测定血清中的抗体水平。G50菌株处理组的总IgE抗体水平显著低于对照组。与对照组相比，G50菌株给药组中OVM特异性IgG1和IgE抗体的反应倾向于较低。这些结果表明，G50菌株具有抑制Th2反应的能力。因此，乳酸乳球菌乳酸亚种G50是一种潜在的益生菌菌株，可用于抑制由Th2反应引起的过敏反应。
