Limosilactobacillus reuteri L26 BiocenolTM and its exopolysaccharide: Their influence on rotavirus-induced immune molecules in enterocyte-like cells.

This study aimed to evaluate the immunomodulatory effect of the probiotic Limosilactobacillus reuteri L26 Biocenol^TM (L26) and its purified exopolysaccharide (EPS) with respect to antiviral innate immune response. In our experiment, we used porcine epithelial IPEC-J2 cells as a model of the intestinal barrier in a homologous infection by porcine Rotavirus A strain OSU6 (RVA). The production of selected molecules of non-specific humoral immunity was evaluated at the mRNA level. The EPS alone significantly increased the level of interferon λ3 (IFN-λ3) mRNA in the non-infected IPEC-J2 cells (P < 0.001). We also tested whether the treatment of IPEC-J2 cells by L26 or EPS influences the replication of RVA by virus titration and real-time PCR. We found that a pre-treatment in combination with subsequent continuous stimulation has no influence on the RVA replication. However, both treatments significantly decreased the RVA-induced production of IFN-λ3 (P < 0.05) and the "SOS" cytokine interleukin 6 (IL-6; P < 0.01), already at the transcription level. In addition, the EPS treatment resulted in significantly increased IL-10 mRNA in the RVA-infected cells. In summary, we assume an immunoregulatory potential of L. reuteri L26 Biocenol^TM and its EPS in the local intestinal antiviral immune response.