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The bacterium Clostridium chauvoei is the causative agent of blackleg in livestock, and vaccination is the most effective means of prevention. The aim of this study was to assess the effect of short-term supplementation with Bacillus toyonensis and Saccharomyces boulardii on the immune response to a C. chauvoei vaccine in sheep. Sheep were vaccinated subcutaneously on day 0 and received a booster dose on day 21, with 2 mL of a commercial vaccine formulated with inactivated C. chauvoei bacterin adsorbed on aluminum hydroxide. Probiotics were orally administered B. toyonensis (3 × 10 8 cfu) and S. boulardii (3 × 10 8 cfu) over five days prior to the first and second doses of the vaccine. Sheep supplemented with B. toyonensis and S. boulardii showed significantly higher specific IgG, IgG1, and IgG2 titers (P<0.05), with approximately 24- and 14-fold increases in total IgG levels, respectively, than the nonsupplemented group. Peripheral blood mononuclear cells from the supplemented group had increased mRNA transcription levels of the IFN-γ, IL2, and Bcl6 genes. These results demonstrate an adjuvant effect of short-term supplementation with B. toyonensis and S. boulardii on the immune response against the C. chauvoei vaccine in sheep., (Copyright © 2021 Elsevier B.V. All rights reserved.)

Macrophages are professional phagocytic cells that play a critical role in initiating immune responses by presenting antigen and phagocytic clearance. The macrophages can be targeted for immunomodulation by beneficial microbes, such as probiotics. The aim of this study is to investigate the protective effect of Saccharomyces boulardii against Clostridium perfringens infection in avian macrophage cell line HD11. In this study, HD11 macrophages were prestimulated with S. boulardii for 6 h and then infected with C. perfringens for 3 h. Results showed that S. boulardii enhanced phagocytosis and bactericidal capacity against C. perfringens by HD11 cells. The S. boulardii effectively promoted the mRNA expression of CD80, CD83, and CD197 cell-surface molecules in C. perfringens-infected HD11 cells. Moreover, we found that prestimulation with S. boulardii reduced the mRNA expression of CD40, toll-like receptor [TLR] 4, and TLR15 induced by C. perfringens and thereby downregulated the mRNA expression of myeloid differentiation primary response 88, TNF receptor associated factor 6, nuclear factor kappa-B p65 subunit, and c-Jun N-terminal kinase genes in HD11 cells. The upregulation of cytokines (interleukin [IL]-6, tumor necrosis factor alpha, and IL-10) and inducible nitric oxide synthase mRNA expression in C. perfringens-infected HD11 cells were noticeably inhibited by S. boulardii pretreatment. Conclusively, these results might provide a new insight into the role of S. boulardii in regulating avian immune defense against C. perfringens invasion and immune escape., (Copyright © 2020. Published by Elsevier Inc.)

Previous studies have suggested that immune system development and weaning stress are closely related to the maturation of gut microbiota. The early-life period is a "window of opportunity" for microbial colonization, which potentially has a critical impact on the development of the immune system. Fecal microbiota transplantation (FMT) and probiotics are often used to regulate gut microbial colonization. This study aims to test whether early intervention with FMT using fecal microbiota from gestation sows combined with Clostridium butyricum and Saccharomyces boulardii (FMT-CS) administration could promote the maturation of gut microbiota and development of immune system in piglets. Piglets were assigned to control ( n = 84) and FMT-CS treatment ( n = 106), which were treated with placebo and bacterial suspension during the first three days after birth, respectively. By 16S rRNA gene sequencing, we found that FMT-CS increased the α-diversity and reduced the unweighted UniFrac distances of the OTU community. Besides, FMT-CS increased the relative abundance of beneficial bacteria, while decreasing that of opportunistic pathogens. FMT-CS also enhanced the relative abundance of genes related to cofactors and vitamin, energy, and amino acid metabolisms during the early-life period. ELISA analysis revealed that FMT-CS gave rise to the plasma concentrations of IL-23, IL-17, and IL-22, as well as the plasma levels of anti-M.hyo and anti-PCV2 antibodies. Furthermore, the FMT-CS-treated piglets showed decreases in inflammation levels and oxidative stress injury, and improvement of intestinal barrier function after weaning as well. Taken together, our results suggest that early-life intervention with FMT-CS could promote the development of innate and adaptive immune system and vaccine efficacy, and subsequently alleviate weaning stress through promoting the maturation of gut microbiota in piglets.

There have been significant efforts toward the development of more efficient vaccines for animal health. A strategy that may be used to improve vaccine efficacy is the use of probiotics. Bovine herpesvirus 5 (BoHV-5) is an example of an important animal pathogen for which vaccines have provided only limited protection. In this study, we examined the use of the probiotics Bacillus toyonensis and Saccharomyces boulardii as a potential immune modulator to improve vaccine efficiency. Thirty, 5-month-old lambs were randomly grouped in three lots of 10 each and vaccinated at days 0, 21 and 42 of the experiment. They grazed on the same pasture and were fed ad libitum twice a day with commercial sheep feed supplemented with either B. toyonensis (1×10 6 CFU/g of feed) or S. boulardii (1×10 7 CFU/g of feed), or non-supplemented feed. The probiotic supplementation was suspended day 28; thereafter, the next 35days, they were fed with the same commercial feed as control group. Animals supplemented with probiotics showed a significant (p>0.001) increased seroconversions against BoHV-5, and higher neutralizing antibodies titres (p>0.05) to BoHV-5 than non-supplemented animals. At 63days of experiment, splenocytes from the supplemented sheep had higher mRNA transcription levels of cytokines IL-10 and IL-17A. These results suggest that these probiotics could provide a promising means of improving vaccine efficacy., (Copyright © 2018 Elsevier Ltd. All rights reserved.)

Interactions between members of the intestinal microbiota and the mucosal immune system can significantly impact human health, and in this context, fungi and food-related yeasts are known to influence intestinal inflammation through direct interactions with specialized immune cells in vivo. The aim of the present study was to characterize the immune modulating properties of the food-related yeast Kluyveromyces marxianus in terms of adaptive immune responses indicating inflammation versus tolerance and to explore the mechanisms behind the observed responses. Benchmarking against a Saccharomyces boulardii strain with probiotic effects documented in clinical trials, we evaluated the ability of K. marxianus to modulate human dendritic cell (DC) function in vitro. Further, we assessed yeast induced DC modulation of naive T cells toward effector responses dominated by secretion of IFNγ and IL-17 versus induction of a Treg response characterized by robust IL-10 secretion. In addition, we blocked relevant DC surface receptors and investigated the stimulating properties of β-glucan containing yeast cell wall extracts. K. marxianus and S. boulardii induced distinct levels of DC cytokine secretion, primarily driven by Dectin-1 recognition of β-glucan components in their cell walls. Upon co-incubation of yeast exposed DCs and naive T cells, S. boulardii induced a potent IFNγ response indicating TH1 mobilization. In contrast, K. marxianus induced a response dominated by Foxp3+ Treg cells, a characteristic that may benefit human health in conditions characterized by excessive inflammation and positions K. marxianus as a strong candidate for further development as a novel yeast probiotic., Competing Interests: I have read the journal’s policy and have the following conflicts to declare. IMS and AB are employees of Chr. Hansen A/S, a manufacturer of probiotic products, and the described work was carried out at Chr. Hansen A/S facilities in Hørsholm, Denmark. This does not alter our adherence to PLOS ONE policies on sharing data and materials.