Abstract

The principle purpose of this study was to investigate the immunomodulatory ability of three microbial strains isolated from Bama County centenarians in activating macrophages, and to characterize the effective component of these strains. A murine macrophage cell line, RAW264.7, was cultured in presence of intact bacterial cells, bacterial cell wall (CW) or cell free extract (CFE). NO, IL-6, TNF-α production and phagocytic activity of co-cultured macrophages were tested. Bifidobacterium adolescentis BBMN23, Bifidobacterium longumBBMN68 and Lactobacillus saliva Ren were demonstrated to enhance the activities of macrophages by increasing the phagocytic activity and NO, IL-6, TNF-α production. The immunomodulatory activities of these microbial strains are mainly due to the CW fraction, although their CFE were also effective. The results of this study indicated that specific substrains of bifidobacterium and lactobacillus from guts of healthy centenarians (Bama County, China) may be of immunomodulatory value, and thus may have the potential to be used as probiotics.

Key words: Bifidobacterium, lactobacillus; RAW 264.7 cells, immunomodulatory activities, bacterial fractions.