Strain-specific immunomodulatory effects of Lactobacillus plantarum strains on birch-pollen-allergic subjects out of season

Lactobacillus plantarum isolated from kefir enhances immune responses and survival of white shrimp (Penaeus vannamei) challenged with Vibrio alginolyticus

Lactobacillus plantarum is known for its probiotics benefit to host, although the effects vary among strains. This study conducted a feeding experiment of three Lactobacillus strains, MRS8, MRS18 and MRS20, which were isolated from kefir and incorporated into the diets of shrimp to evaluate the effects of non-specific immunity, immune-related gene expression, and disease resistance of white shrimp (Penaeus vannamei) against Vibrio alginolyticus. To prepare the experimental feed groups, the basic feed was mixed with different concentrations of L. plantarum strains MRS8, MRS18, and MRS 20, which were incorporated at 0 CFU (control), 1 × 10⁶ CFU (groups 8-6, 18-6, and 20-6), and 1 × 10⁹ CFU (groups 8-9, 18-9, and 20-9) per gram of diet for an in vivo assay. During the rearing period for 28 days of feeding each group, immune responses, namely the total hemocyte count (THC), phagocytic rate (PR), phenoloxidase activity, and respiratory burst were examined on days 0, 1, 4, 7, 14, and 28. The results showed that groups 20-6, 18-9 and 20-9 improved THC, and groups 18-9 and 20-9 improved phenoloxidase activity and respiratory burst as well. The expression of immunity-related genes was also examined. Group 8-9 increased the expression of LGBP, penaeidin 2 (PEN2) and CP, group 18-9 increased the expression of proPO1, ALF, Lysozyme, penaeidin 3 (PEN3) and SOD, and group 20-9 increased the expression of LGBP, ALF, crustin, PEN2, PEN3, penaeidin 4 (PEN4) and CP (p < 0.05). Groups 18-6, 18-9, 2-6, and 20-9 were further used in the challenge test. After feeding for 7 days and 14 days, Vibrio alginolyticus was injected into white shrimp and observed the shrimp survival for 168 h. The results showed that compared to the control, all groups improved the survival rate. Especially, feeding group 18-9 for 14 days improved the survival rate of white shrimp (p < 0.05). After the challenge test for 14 days, the midgut DNA of survival white shrimps was extracted to analyze the colonization of L. plantarum. Among the groups, (6.61 ± 3.58) × 10⁵ CFU/pre shrimp of L. plantarum in feeding group 18-9 and (5.86 ± 2.27) × 10⁵ CFU/pre shrimp in group 20-9 were evaluated by qPCR. Taken together, group 18-9 had the best effects on the non-specific immunity, the immune-related gene expression, and the disease resistance, which might be due to the benefit of the probiotic colonization.

Hygienic behaviors during the COVID-19 pandemic may decrease immunoglobulin G levels: Implications for Kawasaki disease

Background

Due to the coronavirus disease 2019 (COVID-19) pandemic, hygienic behaviors became a new norm since January 2020. The hygiene hypothesis predicts that an excessively hygienic environment may adversely affect human health.

Objective

We quantified the effect of COVID-19 on immunological parameters linked to the hygiene hypothesis.

Methods

We examined age-specific levels of total nonspecific immunoglobulin G (IgG) and IgE in individuals who visited Fukuoka Tokushukai Hospital between 2010 and 2021. Pre-COVID (2010–2019) and COVID (2020–2021) periods were compared.

Results

IgG levels steadily decreased throughout Pre-COVID period. IgG levels fell abruptly from the pre-COVID period to the COVID period in all age groups (P = 0.0271, < 0.3 years; P = 0.0096, 0.3–5 years; P = 0.0074, ≥ 5 years). The declines in IgG in < 0.3 years and that in ≥ 5 years accelerated during the COVID period. IgE levels were seasonal, but did not change noticeably from the pre-COVID to COVID period. IgG levels recorded for patients with Kawasaki disease (KD) (mean 709 mg/dL) were significantly lower than for matched control subjects (826 mg/dL) (P<0.0001).

Discussion

Hygienic behaviors during the COVID-19 outbreak decreased the chance of infection, which may explain the decreases in IgG levels in children and adults. Neonatal IgG declined, possibly because of the decrease in maternal IgG.

Conclusion

Hygienic behaviors decreased the IgG levels in all age groups, from neonates to adults. This downturn in IgG may lead to vulnerability to infections as well as to KD.

Effect of Low-Immunogenic Yogurt Drinks and Probiotic Bacteria on Immunoreactivity of Cow's Milk Proteins and Tolerance Induction-In Vitro and In Vivo Studies

There is no effective therapy for milk allergy. The role of lactic acid bacteria (LAB) and probiotics in protection against allergy-related outcomes is still under investigation. The aim of the study was to evaluate the immunomodulative and therapeutic potential of yogurt drinks in cow's milk allergy (CMA) management. We compared immunoreactivity of α-casein (α-CN), β-casein (β-CN), κ-casein (κ-CN), α-lactalbumin (α-LA), and β-lactoglobulin (β-LG) in 27 yogurt drinks fermented with different basic yogurt cultures, or yogurt cultures enriched with Lactobacillus plantarum and/or Bifidobacterium lactis strains, by competitive ELISA assay. Drinks with the lowest antigenic potential were used as allergoids for CMA therapy. BALB/c mice were sensitized via intraperitoneal injection of α-CN + β-LG mixture with aluminum adjuvant, and gavaged with increasing doses of selected low-immunogenic drinks (YM-basic, or YM-LB-enriched with L. plantarum and B. lactis) to induce tolerance. Milk- or phosphate-buffered saline (PBS)-dosed mice served as controls. Compared to milk, the immunoreactivity of proteins in drinks increased or decreased, depending on the bacterial sets applied for fermentation. Only a few sets acted synergistically in reducing immunoreactivity. The selected low-immunogenic drinks stimulated allergic mice for profiling Th2 to Th1 response and acquire tolerance, and the effect was greater with YM-LB drink, which during long-lasting interventional feeding strongly increased the secretion of regulatory cytokines, i.e., IL-10 and TGF-β, and IgA and decreased IL-4, IgE, and anti-(α-CN + β-LG) IgG1. The studies revealed variations in the potency of yogurt bacteria to change allergenicity of milk proteins and the need for their strict selection to obtain a safe product for allergy sufferers. The YM-LB drink with reduced antigenic potential may be a source of allergoids used in the immunotherapy of IgE mediated CMA, but further clinical or volunteer studies are required.

Gut microbial characteristics of adult patients with allergy rhinitis

Background

Although recent studies have indicated that intestinal microbiota dweller are involved in the pathogenesis of allergy rhinitis (AR), the influence of gut microbiota on AR adult has not been fully elucidated yet. Hence, we carried out this study to uncover the distinctive bacterial taxa that differentiate allergy rhinitis patients from healthy individuals. Feces samples from thirty three AR patients and thirty one healthy individuals were analyzed by 16S rRNA gene sequencing.

Results

Results showed that the bacterial diversity in AR group was significantly higher than that of the non-AR group. Bacterial communities between AR and non-AR group were significantly differentiated as revealed by Principal coordinates analysis (PCoA) and the variation within non-AR were higher than that of the counterpart. Firmicutes, Fusobacteria, Actinobacteria, Cyanobacteria and Chloroflexi were the significantly differed phyla taxa and the top significantly distinguished bacterial genus included Prevotella_9, Phascolarctobacterium, Roseburia, Megamonas, Alistipes, Lachnoclostridium and Fusobacterium. The higher network complexity in AR group were dominated by taxa belonging to Firmicutes. The predicted function, alpha linolenic acid metabolism and bacterial invasion of epithelial cells pathway were higher in non-AR group while gonadotropin-releasing hormone (GnRH) signaling pathway, Fc γ-R mediated phagocytosis and endocytosis were higher in AR patients. Although the bacterial diversity between moderate and severe AR patients showed no significant difference, the significant correlation between featured genus and total nasal symptom score or rhinoconjunctivitis quality of life questionnaire, such as Butyricicoccus and Eisenbergiella, revealed the potential to intervene the AR status by means of gut microbiota.

Conclusions

In conclusion, patients with allergy rhinitis had distinguished gut microbiota characteritics in comparison with healthy controls. The results suggest that gut microbiota might play crucial roles in influencing the course and different symptoms of AR.

Trial registration ChiCTR, ChiCTR1900028613. Registered 29 December 2019, https://www.chictr.org.cn/showproj.aspx?proj=47650.

Probiotic Potential and Safety Evaluation of Enterococcus faecalis OB14 and OB15, Isolated From Traditional Tunisian Testouri Cheese and Rigouta, Using Physiological and Genomic Analysis

Lactic acid bacteria (LAB) strains OB14 and OB15 were isolated from traditional Tunisian fermented dairy products, Testouri cheese and Rigouta, respectively. They were identified as Enterococcus faecalis by the MALDI TOF-MS (matrix assisted laser desorption-ionization time of flight mass spectrometry) biotyper system and molecular assays (species-specific PCR). These new isolates were evaluated for probiotic properties, compared to E. faecalis Symbioflor 1 clone DSM 16431, as reference. The bacteria were found to be tolerant to the harsh conditions of the gastrointestinal tract (acidity and bile salt). They were low to moderate biofilm producers, can adhere to Caco-2/TC7 intestinal cells and strengthen the intestinal barrier through the increase of the transepithelial electrical resistance (TER). Susceptibility to ampicillin, vancomycin, gentamicin and erythromycin has been tested using the broth microdilutions method. The results demonstrated that E. faecalis OB14 and OB15 were sensitive to the clinically important ampicillin (MIC = 1 μg/mL) and vancomycin (MIC = 2 μg/mL) antibiotics. However, Whole Genome Sequencing (WGS) showed the presence of tetracycline resistance and cytolysin genes in E. faecalis OB14, and this led to high mortality of Galleria Mellonella larvae in the virulence test. Hierarchical cluster analysis by MALDI TOF-MS biotyper showed that E. faecalis OB15 was closely related to the E. faecalis Symbioflor 1 probiotic strain than to OB14, and this has been confirmed by WGS using the average nucleotide identity (ANI) and Genome-to-Genome Hybridization similarity methods. According to these results, E. faecalis OB15 seems to be reliable for future development as probiotic, in food or feed industry.

In Vitro Antimicrobial Activity and Probiotic Potential of Bifidobacterium and Lactobacillus against Species of Clostridium

Many Clostridium species are found as commensal members of the intestinal microbiota. However, imbalances of the microbiota may lead to certain infections caused by these microorganisms, mainly Clostridium butyricum, Clostridium difficile, and Clostridium perfringens. In many cases, infection recurrence can occur after antibiotics, indicating the need for novel therapeutic options that act on the pathogens and also restore the microbiota. Herein, the in vitro antimicrobial activity and probiotic potential of clinical and reference strains of Bifidobacterium and Lactobacillus were investigated against Clostridium species. Antimicrobial activity was evaluated by the agar spot test and inhibition of gas production. Then, the probiotic potential of selected strains was assessed by analyzing their coaggregation ability, adhesive properties to host cells and mucin, tolerance to acidic pH and bile salts, and antimicrobial susceptibility profiles. Lactobacillus plantarum ATCC 8014 was the most promising strain based on its inhibitory activity against Clostridium spp. Also, this strain met criteria to be considered a probiotic based on its coaggregation ability, adhesive properties, and tolerance to harsh pH and bile acid salt conditions. The results indicate that among the studied strains, L. plantarum ATCC 8014 presents probiotic potential for controlling infections induced by the studied Clostridium species and should be further evaluated in in vivo animal models.

Lipoteichoic Acid of Probiotic Lactobacillus plantarum Attenuates Poly I:C-Induced IL-8 Production in Porcine Intestinal Epithelial Cells

Probiotics in livestock feed supplements are considered a replacement for antibiotics that enhance gastrointestinal immunity. Although bacterial cell wall components have been proposed to be associated with probiotic function, little evidence demonstrates that they are responsible for probiotic functions in livestock. The present study demonstrated that lipoteichoic acid (LTA) of Lactobacillus plantarum (Lp.LTA) confers anti-inflammatory responses in porcine intestinal epithelial cell line, IPEC-J2. A synthetic analog of viral double-stranded RNA, poly I:C, dose-dependently induced IL-8 production at the mRNA and protein levels in IPEC-J2 cells. Lp.LTA, but not lipoprotein or peptidoglycan from L. plantarum, exclusively suppressed poly I:C-induced IL-8 production. Compared with LTAs from other probiotic Lactobacillus strains including L. delbrueckii, L. sakei, and L. rhamnosus GG, Lp.LTA had higher potential to suppress poly I:C-induced IL-8 production. Dealanylated or deacylated Lp.LTA did not suppress poly I:C-induced IL-8 production, suggesting that D-alanine and lipid moieties in the Lp.LTA structure were responsible for the inhibition. Furthermore, Lp.LTA attenuated the phosphorylation of ERK and p38 kinase as well as the activation of NF-κB, resulting in decreased IL-8 production. Taken together, these results suggest that Lp.LTA acts as an effector molecule to inhibit viral pathogen-induced inflammatory responses in porcine intestinal epithelial cells.

Effects of Lactobacillus plantarum Strain OLL2712 Culture Conditions on the Anti-inflammatory Activities for Murine Immune Cells and Obese and Type 2 Diabetic Mice

Studies on the health-promoting effects of lactic acid bacteria (LAB) are numerous, but few provide examples of the relationship between LAB function and culture conditions. We verified the effect of differences in culture conditions on Lactobacillus plantarum OLL2712 functionality; this strain exhibits anti-inflammatory activity and preventive effects against metabolic disorders. We measured interleukin-10 (IL-10) and IL-12 production in murine immune cells treated with OLL2712 cells prepared under various culture conditions. The results showed that the IL-10-inducing activities of OLL2712 cells on murine immune cells differed dramatically between OLL2712 groups at different culture phases and using different culture medium components, temperatures, and neutralizing pHs. In particular, exponential-phase cells had much more IL-10-inducing activity than stationary-phase cells. We confirmed that the Toll-like receptor 2 (TLR2) stimulation activity of OLL2712 cells depended on culture conditions in conjunction with IL-10-inducing activity. We also demonstrated functional differences by culture phases in vivo; OLL2712 cells at exponential phase had more anti-inflammatory activity and anti-metabolic-disorder effects on obese and diabetic mice than those by their stationary-phase counterparts. These results suggest that culture conditions affect the functionality of anti-inflammatory LAB.IMPORTANCE While previous studies demonstrated that culture conditions affected the immunomodulatory properties of lactic acid bacteria (LAB), few have comprehensively investigated the relationship between culture conditions and LAB functionality. In this study, we demonstrated several culture conditions of Lactobacillus plantarum OLL2712 for higher anti-inflammatory activity. We also showed that culture conditions concretely influenced the health-promoting functions of OLL2712 in vivo, particularly against metabolic disorders. Further, we characterized a novel mechanism by which changing LAB culture conditions affected immunomodulatory properties. Our results suggest that culture condition optimization is important for the production of LAB with anti-inflammatory activity.

Supplementation with Lactobacillus plantarum WCFS1 Prevents Decline of Mucus Barrier in Colon of Accelerated Aging Ercc1-/Δ7 Mice

Although it is clear that probiotics improve intestinal barrier function, little is known about the effects of probiotics on the aging intestine. We investigated effects of 10-week bacterial supplementation of Lactobacillus plantarum WCFS1, Lactobacillus casei BL23, or Bifidobacterium breve DSM20213 on gut barrier and immunity in 16-week-old accelerated aging Ercc1^−/Δ7 mice, which have a median lifespan of ~20 weeks, and their wild-type littermates. The colonic barrier in Ercc1^−/Δ7 mice was characterized by a thin (< 10 μm) mucus layer. L. plantarum prevented this decline in mucus integrity in Ercc1^−/Δ7 mice, whereas B. breve exacerbated it. Bacterial supplementations affected the expression of immune-related genes, including Toll-like receptor 4. Regulatory T cell frequencies were increased in the mesenteric lymph nodes of L. plantarum- and L. casei-treated Ercc1^−/Δ7 mice. L. plantarum- and L. casei-treated Ercc1^−/Δ7 mice showed increased specific antibody production in a T cell-dependent immune response in vivo. By contrast, the effects of bacterial supplementation on wild-type control mice were negligible. Thus, supplementation with L. plantarum – but not with L. casei and B. breve – prevented the decline in the mucus barrier in Ercc1^−/Δ7 mice. Our data indicate that age is an important factor influencing beneficial or detrimental effects of candidate probiotics. These findings also highlight the need for caution in translating beneficial effects of probiotics observed in young animals or humans to the elderly.

In vitro comparison of the effects of probiotic, commensal and pathogenic strains on macrophage polarization

Macrophages are important with respect to both innate and adaptive immune responses and are known to differentiate into pro-inflammatory M1- or anti-inflammatory M2-phenotypes following activation. In order to study how different bacteria affect macrophage polarization, we exposed murine RAW 264.7 macrophages to sixteen different strains representing probiotic strains, pathogens, commensals and strains of food origin. Increased inducible nitric oxide synthase (iNOS) or arginase-1 gene expression indicates M1 or M2 polarization, respectively, and was quantified by qRT-PCR. Strains of Escherichia and Salmonella elevated iNOS expression more so than strains of Enterococcus, Lactobacillus and Lactococcus, indicating that Gram-negative strains are more potent M1 inducers. However, strain-specific responses were observed. For instance, Escherichia coli Nissle 1917 was a poor inducer of iNOS gene expression compared to the other E. coli strains, while Enterococcus faecalis Symbioflor-1 was more potent in this respect compared to all the eleven Gram-positive strains tested. Macrophage polarization was further characterized by quantifying secreted pro- and anti-inflammatory cytokines. Exposure to the pathogen E. coli 042 produced a cytokine profile indicating M1 differentiation, which is in accordance with the PCR data. However, exposure to most strains resulted in either high or low secretion levels of all cytokines tested, rather than a clear M1 or M2 profile. In general, the Gram-negative strains induced high levels of cytokine secretion compared to the Gram-positive strains. Interestingly, strains of human origin had a higher impact on macrophages compared to strains of food origin.

Do probiotics have a role in the treatment of allergic rhinitis? A comprehensive systematic review and meta-analysis

OBJECTIVE

To investigate clinical evidence for the efficacy of probiotics in the treatment of allergic rhinitis (AR).

METHODS

A systematic search was conducted to review the results of all randomized, double-blind, placebo-controlled trials by following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses Statement. Primary outcome measurements were total nasal and ocular symptom scores (SS) and quality of life (QoL) questionnaires. Secondary outcome measurements were individual nasal SS and immunologic parameters.

RESULTS

Twenty-two randomized, double-blind, placebo-controlled studies were included. Seventeen trials showed significant benefit of probiotics clinically, whereas eight trials showed significant improvement in immunologic parameters compared with placebo. All five studies with Lactobacillus paracasei (LP) strains demonstrated clinically significant improvements compared with placebo. Probiotics showed significant reduction in nasal and ocular SS (standardized mean difference [SMD], -1.23, p < 0.001; and SMD, -1.84, p < 0.001; respectively), total, nasal, and ocular QoL scores compared with placebo (SMD, -1.84, p < 0.001; SMD, -2.30, p = 0.006; and SMD, -3.11, p = 0.005; respectively). Although heterogeneity was high, in subgroup analysis, SMD for total nasal and ocular symptoms with patients with seasonal AR and for nasal QoL scores for studies with LP-33 strain were significant and homogenous. Scores of nasal blockage, rhinorrhea, and nasal itching were significantly lower in the probiotic group compared with placebo. The meta-analysis studies SS the Japanese guidelines revealed a significant, homogenous SMD score of -0.34 for individual nasal SS, above the minimal important clinical difference value of 0.3. The T-helper 1 to T-helper 2 ratio was significantly lower in the probiotic group compared with placebo (SMD, -0.78; p = 0.045).

CONCLUSION

Despite high variability among the studies, synthesis of available data provided significant evidence of beneficial clinical and immunologic effects of probiotics in the treatment of AR, especially with seasonal AR and LP-33 strains. With the rising pool of studies, the most promising strains in specific allergies can be revealed and adjuvant therapy with probiotics can be recommended for the treatment of AR.

Interaction of mouse splenocytes and macrophages with bacterial strains in vitro: the effect of age in the immune response

Probiotics influence the immune system, both at the local and systemic level. Recent findings suggest the relation between microbiota and the immune system alters with age. Our objective was to address direct effects of six bacterial strains on immune cells from young and aged mice: Lactobacillus plantarum WCFS1, Lactobacillus casei BL23, Lactococcus lactis MG1363, Bifidobacterium breve ATCC15700, Bifidobacterium infantis ATCC15697, and Akkermansia muciniphila ATCC BAA-835. We used splenocytes and naïve or interferon-γ-stimulated bone marrow-derived macrophages (BMDM) as responder populations. All tested bacterial strains induced phenotypic and cytokine responses in splenocytes and BMDM. Based on magnitude of the cellular inflammatory response and cytokine profiles, two subgroups of bacteria were identified, i.e. L. plantarum and L. casei versus B. breve, B. infantis, and A. muciniphila. The latter group of bacteria induced high levels of cytokines produced under inflammatory conditions, including tumour necrosis factor (TNF), interleukin (IL)-6 and IL-10. Responses to L. lactis showed features of both subgroups. In addition, we compared responses by splenocytes and BMDM derived from young mice to those of aged mice, and found that splenocytes and BMDM derived from aged mice had an increased IL-10 production and dysregulated IL-6 and TNF production compared to young immune cells. Overall, our study shows differential inflammatory responses to distinct bacterial strains, and profound age-dependent effects. These findings, moreover, support the view that immune environment importantly influences bacterial immune effects.

In Vitro Evidence for Immune-Modulatory Properties of Non-Digestible Oligosaccharides: Direct Effect on Human Monocyte Derived Dendritic Cells

Infant formulas containing non-digestible oligosaccharides (NDO) similar to the composition in breast milk or a combination of lactic acid bacteria (LAB) and NDO have been shown to harbor preventive effects towards immune-regulatory disorders. The aim of this study was to investigate the immune-modulatory potential of non-digestible short chain galacto- and long chain fructo-oligosaccharides (scGOS/lcFOS) mimicking the natural distribution of oligosaccharides in human breast milk in presence or absence of certain LAB strains in human monocyte derived dendritic cells (MoDC). Immature human MoDC prepared from peripheral blood of healthy non-atopic volunteers were screened in vitro after stimulation with specific scGOS/lcFOS in presence or absence of LAB. IL-10 and IL-12p70 release was analyzed after 24 hours in cell-free supernatants by enzyme-linked immunosorbent assay (ELISA). A luminex-based assay was conducted to assess further cytokine and chemokine release by MoDC. To investigate the resulting T cell response, stimulated MoDC were co-incubated with naïve T cells in allogeneic stimulation assays and intracellular Foxp3 expression, as well as immune-suppressive capacity was determined. Oligosaccharides did not induce relevant amounts of IL-12p70 production, but did promote IL-10 release by MoDC. Furthermore, scGOS/lcFOS mixtures exerted a significant enhancing effect on LAB induced IL-10 secretion by MoDC while no increase in IL-12p70 production was observed. Blocking toll like receptor (TLR)4 abrogated the increase in IL-10 in both the direct stimulation and the LAB stimulation of MoDC, suggesting that scGOS/lcFOS act via TLR4. Finally, scGOS/lcFOS-treated MoDC were shown to upregulate the number of functional suppressive Foxp3 positive T cells following allogeneic stimulation. Our results indicate anti-inflammatory and direct, microbiota independent, immune-modulatory properties of scGOS/lcFOS mixtures on human MoDC suggesting a possible induction of regulatory T cells (Tregs). The tested combinations of LAB and scGOS/lcFOS might represent a useful dietary ingredient for the maintenance of intestinal homeostasis via the induction of Tregs.

Probiotics in the treatment of chronic rhinoconjunctivitis and chronic rhinosinusitis

Chronic rhinitis and rhinosinusitis (CRS) are relevant health conditions affecting significant percentages of the western population. They are frequently coexisting and aggravating diseases. Both are chronic, noninfectious, and inflammatory conditions sharing to a certain extent important pathophysiologic similarities. Beneficial effects of probiotics are long known to mankind. Research is beginning to unravel the true nature of the human microbiome and its interaction with the immune system. The growing prevalence of atopic diseases in the developed world led to the proposition of the "hygiene hypothesis." Dysbiosis is linked to atopic diseases; probiotic supplementation is able to alter the microbiome and certain probiotic strains have immunomodulatory effects in favour of a suppression of Th-2 and stimulation of a Th1 profile. This review focuses on randomized, double-blind, placebo-controlled trials investigating clinical parameters in the treatment of chronic rhinitis and CRS. An emerging number of publications demonstrate beneficial effects using probiotics in clinical double-blind placebo-controlled (dbpc) trials in allergic rhinitis (AR). Using probiotics as complementary treatment options in AR seems to be a promising concept although the evidence is of a preliminary nature to date and more convincing trials are needed. There are no current data to support the use of probiotics in non-AR or CRS.

Efficacy and safety of the probiotic Lactobacillus paracasei LP-33 in allergic rhinitis: a double-blind, randomized, placebo-controlled trial (GA2LEN Study)

BACKGROUND/OBJECTIVES

An imbalance between Th1 and Th2 cells is involved in allergic rhinitis (AR) that may be improved by probiotics. To test the efficacy of the probiotic Lactobacillus paracasei subsp. paracasei LP-33, a double-blind, placebo-controlled, randomized trial was carried out in patients with AR to grass pollen treated with loratadine and presenting altered quality of life.

SUBJECTS/METHODS

Subjects with persistent AR, symptomatic during the grass pollen season, and a positive skin test or specific immunoglobulin E to grass pollens were included by general practitioners (GPs). All received loratadine for 5 weeks. The primary end point was the improvement in Rhinitis Quality of Life (RQLQ) global score at the fifth week of LP-33 consumption compared with placebo (in addition to loratadine). Secondary end points included nasal and ocular symptoms (individual and total symptom scores), visual analogue scale and time of first exacerbation of the symptoms when loratadine was stopped.

RESULTS

A total of 425 subjects were included. Using intent-to-treat analysis, the RQLQ global score decreased significantly more in the LP-33 group than in the placebo group (P=0.0255, difference=-0.286 (95% confidence interval (CI): -0.536; -0.035)). No significant differences were noted for the change of the rhinitis total symptom score 5 global score between groups (P=0.1288, difference=-0.452 (95% CI: -1.036; 0.132)). Significant differences in ocular symptoms (RQLQ) were observed between groups (P=0.0029, difference=-0.4087 (95% CI: -0.6768; -0.1407)).

CONCLUSIONS

This study performed by GPs shows that LP-33 improves the quality of life of subjects with persistent AR who are currently being treated with an oral H1-antihistamine. Whereas nasal symptoms had not changed, ocular symptoms had consistently improved.

Oral delivery of a probiotic induced changes at the nasal mucosa of seasonal allergic rhinitis subjects after local allergen challenge: a randomised clinical trial

Objective

To determine effects of probiotic consumption on clinical and immunological parameters of seasonal allergic rhinitis (SAR) in an out-of-season single nasal allergen challenge.

Methods

In a study registered at ClinicalTrials.Gov (NCT01123252), a 16-week dietary intervention was undertaken in 60 patients with allergic rhinitis (>16 years old). Using a double-blinded, placebo-controlled anonymised design, the patients were divided equally into two groups. One group was given a dairy drink containing Lactobacillus casei Shirota to ingest daily while the other consumed a similar drink without bacteria. Participants attended the clinic on two consecutive days before the intervention and then again at the end of the study period. On the first day of each 2-day visit, following clinical examination, assessments were made of total nasal symptoms scores and peak nasal inspiratory flow. Nasal scrapings, nasal lavage and blood were collected for laboratory analyses of cellular phenotypes, soluble mediator release and in vitro responses to pollen allergen. These procedures were repeated 24 hours following nasal allergen challenge.

Results

Prior to and following intervention there were no detectable differences between study groups in measured clinical outcome. After intervention, there were differences between groups in their percentages of CD86+ epithelial cells (p = 0.0148), CD86+CD252+ non-epithelial cells (p = 0.0347), sIL-1RII release (p = 0.0289) and IL-1β (p = 0.0224) levels at the nasal mucosa. Delivery of probiotic also suppressed production of sCD23 (p = 0.0081), TGF-β (p = 0.0283) and induced increased production of IFN-γ (p = 0.0351) in supernatants of cultured peripheral blood.

Conclusions & Clinical Relevance

This study did not show significant probiotic-associated changes with respect to the primary clinical endpoint. An absence of overt clinical benefit may be due to an inability of single nasal challenges to accurately represent natural allergen exposure. Nevertheless, oral delivery of probiotics produced changes of the immunological microenvironment at the nasal mucosa in individuals affected by SAR.

Trial Registration

ClinicalTrials.Gov NCT01123252

In vivo evaluation of safety and toxicity of a Lactobacillus jensenii producing modified cyanovirin-N in a rhesus macaque vaginal challenge model

Sexual transmission of human immunodeficiency virus type 1 (HIV-1) across the cervicovaginal mucosa in women is influenced by many factors including the microbiota and the presence of underlying inflammation. It is important that potential HIV preventative agents do not alter the mucosal environment in a way that enhances HIV acquisition. We examined the impact of a "live" microbicide on the vaginal mucosal environment in a rhesus macaque repeated vaginal simian-HIV (SHIVSF162P3) challenge model. The microbicide contained a human vaginal Lactobacillus jensenii expressing the HIV-1 entry inhibitor, modified Cyanovirin-N (mCV-N), and henceforth called LB-mCV-N. Macaques were colonized vaginally each week with LB-mCV-N and sampled six days after colonization for culturable bacteria, pH and cervical-vaginal cytokines during the duration of the six-week study. We show that macaques that retained the engineered LB-mCV-N strain in their vaginal microbiota, during SHIV challenge, had lower pH, when colonization levels were higher, and had no evidence of inflammatory cytokines. Indeed, Interleukin-13, a mediator of inflammation, was detected less often in LB-mCV-N colonized macaques than in controls and we found higher levels of Interleukin 1 receptor antagonist (IL-1RA) in LB-mCV-N colonized macaques during the SHIV challenge period. We noted an inverse correlation between levels of mucosal IL-1RA and peak plasma viral load, thus higher IL-1RA correlated with lower viral load in LB-mCV-N treated macaques. These data support the use of LB-mCV-N as a safe "live" microbicide and suggest that lactobacilli themselves may positively impact the mucosal environment.

Lactobacillus: host-microbe relationships

Lactobacilli are a subdominant component of the human intestinal microbiota that are also found in other body sites, certain foods, and nutrient-rich niches in the free environment. They represent the types of microorganisms that mammalian immune systems have learned not to react to, which is recognized as a potential driving force in the evolution of the human immune system. Co-evolution of lactobacilli and animals provides a rational basis to postulate an association with health benefits. To further complicate a description of their host interactions, lactobacilli may rarely cause opportunistic infections in compromised subjects. In this review, we focus primarily on human-Lactobacillus interactions. We overview the microbiological complexity of this extraordinarily diverse genus, we describe where lactobacilli are found in or on humans, what responses their presence elicits, and what microbial interaction and effector molecules have been identified. The rare cases of Lactobacillus septicaemia are explained in terms of the host impairment required for such an outcome. We discuss possibilities for exploitation of lactobacilli for therapeutic delivery and mucosal vaccination.

Cell surface-associated compounds of probiotic lactobacilli sustain the strain-specificity dogma

Probiotic lactobacilli can positively impact on the health status of targeted (diseased) populations but efficacy depends strongly on the strain employed and the molecular basis for this phenomenon is poorly understood. This review discusses the current state-of-the-art in the field of molecular probiotic-host interactions, focusing on subtle strain-specific differences in the biochemical characteristics of cell surface-associated probiotic ligands and the consequences thereof for the immune responses elicited. This research is bound to enhance our understanding of strain-specificity in relation to probiotic functionality and will allow molecular science-based design of screening and characterization assays targeted to improved selection of probiotic candidate strains. Moreover, identified bioactive effector molecules could be isolated or produced for administration in a more pharmacological regime.

Developments in the field of allergy in 2011 through the eyes of Clinical and Experimental Allergy

As in previous years, we felt it would be of value to our readership to summarize the new information provided by the authors who have published in Clinical and Experimental Allergy in 2011 and set this in the context of recent advances in our understanding of the pathogenesis and management of allergic disease in all its many manifestations. In 2011, about 210 articles were published in Clinical and Experimental Allergy including editorials, reviews, opinion articles, guidelines, letters, book reviews and of course at the heart of the journal, papers containing original data. As before, this review is divided into sections based on the way the journal is structured, although this year we have grouped together all the papers dealing with mechanisms of allergic disease, whether they involve patients (clinical mechanisms), pure in vitro studies (basic mechanisms) or animal models (experimental models), as we felt this was a more coherent way to deal with the subject. In the field of asthma and rhinitis, the relationship between airway inflammation and airway dysfunction was of perennial interest to investigators, as were phenotypes and biomarkers. Aspirin hypersensitivity appeared in studies in several papers and there was new interest in asthma in the elderly. The mechanisms involved in allergic disease describe advances in our understanding of T cell responses, the relationship between inflammation and disease, mast cell and basophil activation, steroid resistance and novel therapies. In the section dealing with epidemiology, studies seeking to identify risk factors for allergic disease including vitamin D are prominent, as once again are studies investigating gene-environment interactions. The clinical allergy section focuses on drug allergy, food allergy and immunotherapy. The area of oral immunotherapy for food allergy is well covered and we were grateful to Stephen Durham for guest editing an outstanding special issue on immunotherapy in the centenary year of Leonard Noon's pioneering work. Lastly, in the field of allergens, the interest in component-resolved diagnosis continues to grow and there are also articles describing important novel cultivars and the effect of food processing on the allergenic properties of foods. Another terrific year, full of important and high-quality work,which the journal has been proud to bring to the allergy community.

Influence of fermented milk products, prebiotics and probiotics on microbiota composition and health

The gut microbiota is a highly diverse and relative stabile ecosystem increasingly recognized for its impact on human health. The homeostasis of microbes and the host is also referred to as eubiosis. In contrast, deviation from the normal composition, defined as dysbiosis, is often associated with localized diseases such as inflammatory bowel disease or colonic cancer, but also with systemic diseases like metabolic syndrome and allergic diseases. Modulating a gut microbiota dysbiosis with nutritional concepts may contribute to improving health status, reducing diseases or disease symptoms or supporting already established treatments. The gut microbiota can be modulated by different nutritional concepts, varying from specific food ingredients to complex diets or by the ingestion of particular live microorganisms. To underpin the importance of bacteria in the gut, we describe molecular mechanisms involved in the crosstalk between gut bacteria and the human host, and review the impact of different nutritional concepts such as pre-, pro- and synbiotics on the gastrointestinal ecosystem and their potential health benefits. The aim of this review is to provide examples of potential nutritional concepts that target the gut microbiota to support human physiology and potentially health outcomes.

Characterization of candidate anti-allergic probiotic strains in a model of th2-skewed human peripheral blood mononuclear cells

BACKGROUND

Pre-clinical and clinical studies have evaluated the efficacy of probiotics in allergy. However, predictive in vitro systems for rational strain selection are still missing.

METHODS

We developed a novel in vitro screening system for the characterization of probiotics with anti-allergic potential. In this model, human peripheral blood mononuclear cells (PBMC) from healthy donors (n = 68) were skewed towards a Th2 cytokine phenotype by culture with IL-4 and anti-CD40, to resemble cells from allergic donors. Th2-skewed cells were then co-cultured with probiotics; a total of 35 strains were tested. Levels of IFN-γ, IL-10, IL-5 and 7 additional cytokines in culture supernatants were determined by ELISA or multiplex assay. Gene expression was assessed by real-time PCR. For validation, splenocytes from ovalbumin-primed mice and PBMC from grass-allergic donors were restimulated with respective antigen and co-cultured with probiotics, and cytokine profiles were correlated.

RESULTS

Culture with IL-4 and anti-CD40 antibody induced secretion of IL-5 from PBMC, indicative of induction of a Th2 phenotype. Cytokine profiles induced by probiotics were strain specific even though species- and genus-specific clustering was observed for many strains by principal component analysis. This was paralleled by mRNA levels of the corresponding genes such as increased Tbet and reduced GATA-3 gene expression. Cytokine profiles induced by probiotics in PBMC stimulated with IL-4 and anti-CD40 correlated with those obtained from allergen-stimulated murine splenocytes or human PBMC from grass-allergic donors.

CONCLUSIONS

Cytokine profiling of probiotic strains with IL-4-/anti-CD40-stimulated PBMC allowed to determine the effect of probiotics on Th2-skewed cells and thus to classify probiotic strains with anti-allergic potential.

Immune-modulatory effect of probiotic Bifidobacterium lactis NCC2818 in individuals suffering from seasonal allergic rhinitis to grass pollen: an exploratory, randomized, placebo-controlled clinical trial

BACKGROUND/OBJECTIVES

Probiotics are defined as 'living micro-organisms that when administered in adequate amounts confer a health benefit to the host'. Different probiotic strains have been investigated for beneficial effects on allergic disorders. The purpose of the current study was to evaluate the effect of orally administering the probiotic Nestlé culture collection (NCC)2818 Bifidobacterium lactis strain on immune parameters and nasal symptom scores in subjects suffering from seasonal allergic rhinitis (SAR).

SUBJECTS/METHODS

The study was a double-blinded, parallel, randomized placebo-controlled trial conducted during the peak of the pollen season. Adult subjects with clinical history of SAR and positive skin prick test to grass pollen were recruited. The subjects received B. lactis NCC2818 or placebo for 8 weeks and completed symptom questionnaires every week. Whole blood was collected at baseline (V1), 4 weeks (V2) and 8 weeks (V3) to measure immune parameters.

RESULTS

Concentrations of Th-2 cytokines, secreted by stimulated blood lymphocytes, were significantly lower in the probiotic group compared with the placebo group at V3 (interleukin (IL)-5, P=0.016; IL-13, P=0.005). Total nasal symptom scores were significantly lower in the second month of the study (weeks 5-8) in the probiotic group compared with the placebo group (P=0.03). Also, percentages of activated CD63 expressing basophils were significantly lower in the probiotic group at V2 (P=0.02).

CONCLUSIONS

Oral administration of the probiotic NCC2818 mitigates immune parameters and allergic symptoms during seasonal exposure. These promising results warrant that B. lactis NCC2818 be investigated further in large-scale trials for management of respiratory allergy.

β-Glucans are involved in immune-modulation of THP-1 macrophages

SCOPE

We aimed to examine different immunological aspects of β-glucans derived from different food sources (oat, barley and shiitake) on phorbol myristate acetate (PMA)-differentiated THP-1 macrophages. Commercially purified barley β-glucan (commercial BG) and lentinan were included to compare β-glucans from the same origin but different degree of purity and processing.

METHODS AND RESULTS

Chemical composition and molecular weight distribution of β-glucan samples were determined. Inflammation-related gene expression kinetics (IL-1β, IL-8, nuclear factor kappa B [NF-κB] and IL-10) after 3, 6 and 24 h of stimulation with 100 μg/mL β-glucan were investigated. All tested β-glucans mildly upregulated the observed inflammation-related genes with differential gene expression patterns. Similar gene expression kinetics, but different fold induction values, was found for the crude β-glucan extracts and their corresponding commercial forms. Pre-incubation of THP-1 macrophages with β-glucans prior to lipopolysaccharide (LPS) exposure decreased the induction of inflammation-related genes compared to LPS treatment. No production of nitric oxide (NO) and hydrogen peroxide (H₂O₂) was detected in β-glucan stimulated THP-1 macrophages. Phagocytic activity was not different after stimulation by β-glucan samples.

CONCLUSION

Based on these in vitro analyses, it can be concluded that the analysed β-glucans have varying levels of immunomodulating properties, which are likely related to structure, molecular weight and compositional characteristic of β-glucan.

Emerging molecular insights into the interaction between probiotics and the host intestinal mucosa

Probiotic bacteria can modulate immune responses in the host gastrointestinal tract to promote health. The genomics era has provided novel opportunities for the discovery and characterization of bacterial probiotic effector molecules that elicit specific responses in the intestinal system. Furthermore, nutrigenomic analyses of the response to probiotics have unravelled the signalling and immune response pathways which are modulated by probiotic bacteria. Together, these genomic approaches and nutrigenomic analyses have identified several bacterial factors that are involved in modulation of the immune system and the mucosal barrier, and have revealed that a molecular 'bandwidth of human health' could represent a key determinant in an individual's physiological responsiveness to probiotics. These approaches may lead to improved stratification of consumers and to subpopulation-level probiotic supplementation to maintain or improve health, or to reduce the risk of disease.

Intestinal microbiota in human health and disease: the impact of probiotics

The complex communities of microorganisms that colonise the human gastrointestinal tract play an important role in human health. The development of culture-independent molecular techniques has provided new insights in the composition and diversity of the intestinal microbiota. Here, we summarise the present state of the art on the intestinal microbiota with specific attention for the application of high-throughput functional microbiomic approaches to determine the contribution of the intestinal microbiota to human health. Moreover, we review the association between dysbiosis of the microbiota and both intestinal and extra-intestinal diseases. Finally, we discuss the potential of probiotic microorganism to modulate the intestinal microbiota and thereby contribute to health and well-being. The effects of probiotic consumption on the intestinal microbiota are addressed, as well as the development of tailor-made probiotics designed for specific aberrations that are associated with microbial dysbiosis.