Exopolysaccharides from Limosilactobacillus reuteri: their influence on in vitro activation of porcine monocyte-derived dendritic cells - brief report

The aim of this study was to evaluate the immunomodulatory potential of two alpha-D-glucans from Limosilactobacillus reuteri L26 Biocenol (TM) (EPS-L26) and L. reuteri DSM17938 (EPS-DSM17938), with respect to their influence on in vitro activation of porcine dendritic cells (DCs). We used immature DCs differentiated from porcine blood monocytes under in vitro conditions. Based on the surface expression of MHC II and costimulatory CD80/86 molecules, we showed that both used EPSs favour the maturation of monocyte-derived DCs (MoDCs) similarly to the commonly used stimulant tumour necrosis factor alpha (TNF-alpha). In contrast to TNF-alpha stimulation, MoDCs treated with both used EPSs significantly up-regulated the mRNA levels not only for interleukin (IL)-10 (P < 0.0001 for EPS-DSM17938; P = 0.0037 for EPS-L26), but also for IL-12 (P = 0.0176 for EPS-DSM17938; P = 0.0019 for EPS-L26). These cytokines are known to regulate T-cell kinetics and play a key role in maintaining immune homeostasis. Interestingly, only relatively linear alpha-D-glucan (EPS-DSM17938) significantly increased gene expression of the major pro-inflammatory cytokine IL-1 beta (P = 0.0011) and the "SOS" cytokine IL-6 (P = 0.0127). However, it is important to highlight the need for further studies aimed at cytokine kinetics in DCs, as well as a co-culture study with allogenic T-lymphocytes.