Lactobacilli naturally present in the neonatal gut are believed to be beneficial for the human hosts and are investigated as potential probiotics. In this study, we aimed to characterize six Lactobacillus plantarum strains derived from the feces of a breast-fed infant, for the development of new probiotic cultures. Our attention was focused on L. plantarum in reason of the presence, within such species, of both pro-technological and probiotic strains, i.e., a combination of particular interest to design tailored probiotic starter cultures for developing countries. The bacterial isolates exhibiting lactobacilli-like phenotypic characteristics were identified as members of the L. plantarum group by 16S rRNA gene sequencing, and their diversity was evaluated by randomly amplified polymorphic DNA (RAPD) PCR patterns. The selected strains were screened for probiotic potential through in vitro tests. Firstly, bacterial survival was evaluated in an in vitro system simulating the human oro-gastrointestinal tract, using also milk as a carrier matrix. Besides, physiological traits such as antibiotic susceptibility, antimicrobial activity against selected enteric pathogens, and adhesion to abiotic surfaces and to gastric mucin were studied. Considering the resistance to simulated gastrointestinal digestion and the results from the biofilm and mucin adhesion tests, a strain-denominated L. plantarum LSC3 was selected for further evaluation of in vitro adhesion ability to intestinal mucosa and immunomodulatory activities. L. plantarum LSC3 was able to adhere efficiently to human enterocyte-like cells (Caco-2 cells), and decreased IL-8 transcription while increasing IL-10 mRNA level, as revealed by transcriptional analysis on LPS-stimulated human (THP-1) macrophages. Our results highlight that L. plantarum LSC3 fulfills major in vitro probiotic criteria as well as interesting immunostimulatory properties, and thus may be a promising candidate for further in vivo studies aiming at the development of novel probiotic starter cultures.
Context: Royal jelly (RJ) has long been used to promote human health.Objective: The current study investigated the preventive effects of RJ against the development of a systemic and intestinal immune response in mice allergic to cow’s milk proteins.Materials and methods: Balb/c mice treated orally for seven days with RJ at doses of 0.5, 1 and 1.5 g/kg were sensitized intraperitoneally with β-lactoglobulin (β-Lg). Serum IgG and IgE anti-β-Lg were determined by an enzyme-linked immunosorbent assay (ELISA). Plasma histamine levels, symptom scores and body temperature were determined after in vivo challenge to β-Lg. Jejunums were used for assessment of local anaphylactic responses by an ex vivo study in Ussing chambers and morphologic changes by histological analysis.Results: RJ significantly decreased serum IgG (31.15–43.78%) and IgE (64.28–66.6%) anti-β-Lg and effectively reduced plasma histamine level (66.62–67.36%) (p < 0.001) at all the doses tested. Additionally, no clinical symptoms or body temperature drops were observed in RJ-pretreated mice. Interestingly, RJ significantly reduced (p < 0.001) intestinal dysfunction by abolishing the secretory response (70.73–72.23%) induced by sensitization and prevented length aberrations of jejunal villi by 44.32–59.01% (p < 0.001).Discussion and conclusions: We speculate that using RJ may help prevent systemic and anaphylactic response in allergic mice. These effects may be related to its inhibitory effects on the degranulation of mast cells.
Problem statement: Cow's Milk Allergy (CMA) is a common disease in childhood. Pathophysiological mechanisms involved in gastrointestinal symptoms are relatively poorly understood. Approach: Therefore, an experimental model of intestinal anaphylaxis was needed to approach the problem. The aim of this study was to examine the effect of the parenteral sensitization to whey proteins through immune response and local intestine inflammation using a murine model of allergy. Sensitization of Balb/c mice with β-lactoglobulin (β-Lg) or whey was performed in presence of Alum Al (OH3). Mice were analyzed for β-Lg or whey specific serum antibodies by ELISA. Local anaphylactic responses were performed in vitro in using chamber by intestine challenge with β-Lg or whey. Histological study was used to assess gut inflammation. Results: The sensitization induced the production of anti-β-Lg or anti whey IgG, IgG1, IgG2a and IgE with a high IgG1/IgG2a ratio translating Th2 type response. The addition of β-Lg or whey to the serosal side of the mouse intestinal epithelium in using chamber produced electrogenic chloride secretion as shown by Isc stimulation. Histological findings were mild with villi atrophy and lymphocyte hyperplasia. Conclusion: After sensitization, the mice became prone to developing anaphylactic response and may be useful experimental model for mechanistic studies of CMA or for hydrolyzed formulae.
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