Lactobacillus reuteri and Staphylococcus aureus differentially influence the generation of monocyte‐derived dendritic cells and subsequent autologous T cell responses

Abstract

IntroductionIn early‐life, the immature mucosal barrier allows contact between the gut microbiota and the developing immune system. Due to their strategic location and their ability to sample luminal antigen, dendritic cells (DC) play a central role in the interaction of microbes and immune cells in the gut. Here, we investigated how two bacteria associated with opposite immune profiles in children, that is, Lactobacillus (L.) reuteri and Staphylococcus (S.) aureus, influenced the differentiation of monocytes in vitro as well how the generated DC impacted T cell responses.MethodsWe exposed monocyte cultures to cell‐free supernatants (CFS) from these bacteria during their differentiation to DC.ResultsThe presence of L. reuteri‐CFS during DC differentiation resulted in DC with a more mature phenotype, in terms of up‐regulated surface markers (HLA‐DR, CD86, CD83, CCR7) and enhanced cytokine production (IL6, IL10, and IL23), but had a reduced phagocytic capacity compared with non‐treated monocyte‐derived DC (Mo‐DC). However, upon LPS activation, L. reuteri‐CFS‐generated DC displayed a more regulated phenotype than control Mo‐DC with notable reduction of cytokine responses both at mRNA and protein levels. In contrast, S. aureus‐CFS‐generated DC were more similar to control Mo‐DC both without and after LPS stimulation, but they were still able to induce responses in autologous T cells, in the absence of further T cell stimulation.ConclusionsWe show that bacterial signals during DC differentiation have a profound impact on DC function and possibly also for shaping the T cell pool.

Crying Time and RORγ/FOXP3 Expression in Lactobacillus reuteri DSM17938-Treated Infants with Colic: A Randomized Trial

“…18,19 Moreover, some studies thus far conducted only in vitro or in animal models, have also demonstrated an anti-inflammatory effect of L reuteri, which could at least partly explain the clinical effect. [20][21][22] Despite growing data confirming the clinical efficacy of L reuteri on colic in breastfed infants, [23][24][25] the role of this bacteria remains under investigation.…”

Extremely Preterm Infants Have Significant Alterations in Their Conventional T Cell Compartment during the First Weeks of Life

“…A recent meta-analysis of prospective randomized controlled trials evaluating whether the use of probiotics can prevent feeding intolerance and NEC in premature infants shows encouraging results, but it was also concluded that there is still insufficient data with regard to the benefits and potential adverse effects in ELBW infants (15). Although several studies have demonstrated that Lactobacillus reuteri modulates the innate and acquired immune responses in humans both in vitro and in vivo (16)(17)(18)(19)(20)(21), the influence of L. reuteri supplementation on the phenotypic and functional characteristics and gut-homing properties of T cells of preterm, and particularly ELBW, infants has not been studied.…”

MetaLonDA: a flexible R package for identifying time intervals of differentially abundant features in metagenomic longitudinal studies

“…Utilization of MetaLonDA in this cohort demonstrates that Escherichia establishes a significant community in Russian infants from day 550 to 946 with little variability. MetaLonDA also defined specific time intervals during which other bacterial genera (e.g., Lactobacillus , Leptotrichia , Klebsiella ) previously associated as protective or instigating of type 1 diabetes (T1D) were differentially abundant [ 33 , 34 ]. Moreover, MetaLonDA established that up until day 629, Finnish infants present an additional shift in Proteobacteria with an overabundance of genera that are known to be implicated in human disease, including Campylobacter , Haemophilus , Klebsiella , and Neisseria .…”