关键词: 乳杆菌, 淋巴细胞增殖, 筛选模型, 免疫活性, MTT 比色法

Abstract:

Objective: To evaluate the immunomodulation effect of seven Lactobacillus strains in vitro and to explore the application of mouse spleen lymphocytes in the selection of lactic acid bacteria with immunological activity. Methods: The effects of viable/heat-killed Lactobacillus strains belonging to different species at varying cell suspension concentrations on mouse lymphocyte proliferation were explored by MTT assay in vitro. Results: Either viable or heat-killed Lactobacilli alone could accelerate the proliferation of spleen cells in a dose-dependent manner. The most obvious immunomodulation effect was observed when vaiable/dead Lactobacillus strain suspension was at 107 CFU/mL (bacteria/cell ratio of 10:1) (P ＜ 0.05). Meanwhile, the immunomodulation effect of living Lactobacillus strains was better than that of heat-killed Lactobacillus strains (P＜0.05). The lymphocyte proliferation indexes (PI value) of Lactobacillus reuteri, Lactobacillus johnsoni and Lactobacillus fermentum were significantly higher than that of ConA-induced group (P＜0.05). Conclusion: Spleen lymphocyte-based assay can be used as a useful primary indicator for the selection of candidate strains and an animal model for the evaluation of immunological activity.

Key words: Lactobacillus, lymphocyte proliferation, screening model, immunological activity, MTT assay