Objective:

This study aimed to assess the impact of a wild strain of Lactobacillus plantarum (PL4) on the production of IL-10 and T helper (Th) 17 related cytokines, including interleukin (IL)-17A, IL-17F, IL-21, and IL-22, compared to a standard probiotic strain, Lactobacillus plantarum. PL4 was isolated from Lighvan cheese and its probiotic potential was proved before. Probiotics with immune regulatory activity might be effective in the case of Th17 cells and IL-17-related pathways, which are involved in the pathogenesis and are associated with a worse result of some diseases. These regulatory effects might be arising from different bacterial cell substances.

Materials and Methods:

Peripheral blood mononuclear cells (PBMC) were treated with cell debris and cell extract of both strains with and without human anti-CD3/CD28 T-cell activator beads in order to determine immunomodulatory effects of the strains. A number of cytokines were assessed.

Results:

Bacterial cell debris and extract had no stimulatory or suppressive effects on the Th17 related cytokines and only the debris of both strains increased IL-10 production significantly. When PBMC pretreated with bacterial cell debris or extracts was stimulated with anti-CD3/CD28 beads, both strains down-regulated IL-17F. PL4 extract could decrease IL-21 and IL-17A but conversely, its debris increased these cytokines.

Conclusion:

Pretreatment with PL4 extract induced lower levels of IL-17A, IL-17F, IL-21 and IL-10 in stimulated PBMCs, implying an anti-inflammatory potential of this strain. Significant differences among the effects of the strains confirmed strain dependency of their immunomodulatory properties.

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