Experiment Study About The Bifidobacterium And The Whole Peptidoglycan Of Bifidobacterium Effection On Dendritic Cell Come From Cord Blood

【Objective】To explore in vitro the effect of Bifidobacterium and the Whole Peptidoglycan of Bifidobacterium (WPG) on proliferation, maturation and immunoregulation of DCs from the cord blood monocyte, investigate the mechanism of Bifidobacterium that prevents and cures the immunodisturbance disease and provide further evidence of the exploitation of probiotics and its active component.【Methods】Cord blood monocular cells (CBMC) of normal expectant mother was isolated, cultured and induced to become immature DCs with GM-CSF and IL-4. Bifidobacterium bifidum and WPG of different doses of Bifidobacterium bifidum (1μg/ml-8μg/ml) was added into the experimental groups, respectively, Lipopolysaccharide (LPS) was added into the positive control group, culture medium was added into the negative control group. The change of the shape of DCs was observed continuously with phase-contrast microscope and electron microscope, the expression of CD83 and CD1a of DCs was detected with flow Cytometry (FC), the capability of DCs to stimulate the proliferation of allogeneic T lymphocytes was examined with MTT assay, the content of IL-12p70 and IL-10 in the culture supernatant of DCs with enzyme linked immunosorbent assay (ELISA).【Results】(1) After induced with GM-CSF and IL-4, DCs from CBMC stimulated by the Bifidobacterium and WPG had typical morphology of mature DCs characterized with enation. MLR test showed that the capability of the induced DCs to stimulate the proliferation of allogeneic T lymphocytes and secret IL-12p70 and IL-10 was more competent than that of the negative group (P<0.01), and that of the experimental group stimulated with 5μg/ml WPG was significant more competent than other groups, and its expression of CD83 and CD1a was enhanced than other groups.⑵There was no significant difference between the experimental group co-cultured with Bifidobacterium bifidum and the experimental group stimulated with 2μg/ml WPG in the capability of DCs to stimulate the proliferation of allogeneic T lymphocytes and secret IL-12p70 and IL-10, (P>0.05)⑶T he level of IL-12p70 and IL-10 secreted by DCs was dose-dependent upon the concentration of WPG while the concentration of WPG was ranged from 1μg/ml to 5μg/ml. The level of IL-12p70 and IL-10 reached the peak when the concentration of WPG was 5μg/ml and decreased when the concentration of WPG was 6μg/ml, and there is no significant difference between the experimental group stimulated with 8μg/ml WPG and the negative group (P>0.05).【Conclusions】1. Bifidobacteria and WPG have effects on maturation of DCs from CBMCs.2. It is possible mechanism that Bifidobacteria and WPG can prevent and cure the immunodisturbance disease by excite DCs secreting cytokine to regulate the balance of Th1/Th2.3. WPG is more effective than Bifidobacterium in the maturation degree of CB-MDDCs and cytokines production of CB-MDDCs , WPG is one of the main active ingredients of Bifidobacterium; The immunomodulation of WPG in variant dosages presents a dose-dependent manner in definite dosage range of WPG. It suggested that Probiotics can be beneficial only in a certain range of dosage.