The Evaluation of the Effect of Tolerogenic Probiotics on the Maturation of Healthy Dendritic Cells versus Immature Dendritic Cells.

Background: Dendritic cells, (DCs) as one of the important immune cell populations, are responsible for the initiation, development, and control of acquired immune responses. Myeloid dendritic cells can be used as a vaccine for several autoimmune diseases and cancers. Tolerogenic probiotics with regulatory properties can affect the maturation and development of immature dendritic cells (IDC) into mature DCs with certain immunomodulatory effects.

Objective: To assess the immunomodulatory effect of Lactobacillus rhamnosus and Lactobacillus delbrueckii, as two tolerogenic probiotics, in the differentiation and maturation of myeloid dendritic cells.

Methods: The IDCs were derived from the healthy donors in GM-CSF and IL 4 medium. Mature DCs (MDC) were produced with L. delbrueckii, L. rhamnosus, and LPS from IDCs. Real-Time PCR and flow cytometry were used to confirm the DC maturation and to determine DC markers as well as IDO, IL10, and IL12 expression levels, respectively.

Results: Probiotic-derived DCs showed a significant reduction in the level of HLA-DR (P≤0.05), CD86 (P≤0.05), CD80 (P≤0.001), CD83 (P≤0.001), and CD1a. Also, the expression of IDO (P≤0.001) and IL10 increased while IL12 expression decreased (P≤0.001).

Conclusion: Our findings revealed that tolerogenic probiotics could induce regulatory DCs by reducing co-stimulatory molecules along with increasing the expression of IDO and IL10 during the differentiation process. Therefore, the induced regulatory DCs probably can be used in the treatment of various inflammatory diseases.