An intranasal administration of Lactococcus lactis strains expressing recombinant interleukin-10 modulates acute allergic airway inflammation in a murine model

Lactococcus lactis as an Interleukin Delivery System for Prophylaxis and Treatment of Inflammatory and Autoimmune Diseases

Target delivery of therapeutic agents with anti-inflammatory properties using probiotics as delivery and recombinant protein expression vehicles is a promising approach for the prevention and treatment of many diseases, such as cancer and intestinal immune disorders. Lactococcus lactis, a Lactic Acid Bacteria (LAB) widely used in the dairy industry, is one of the most important microorganisms with GRAS status for human consumption, for which biotechnological tools have already been developed to express and deliver recombinant biomolecules with anti-inflammatory properties. Cytokines, for  example, are immune system communication molecules present at virtually all levels of the immune response. They are essential in cellular and humoral processes, such as hampering inflammation or adjuvating in the adaptive immune response, making them good candidates for therapeutic approaches. This review discusses the advances in the development of new therapies and prophylactic approaches using LAB to deliver/express cytokines for the treatment of inflammatory and autoimmune diseases in the future.

Exploring the potential impact of probiotic use on drug metabolism and efficacy

Probiotics are frequently consumed as functional food and widely used as dietary supplements, but are also recommended in treating or preventing various gastrointestinal diseases. Therefore, their co-administration with other drugs is sometimes unavoidable or even compulsory. Recent technological developments in the pharmaceutical industry permitted the development of novel drug-delivery systems for probiotics, allowing their addition to the therapy of severely ill patients. Literature data regarding the changes that probiotics could impose on the efficacy or safety of chronic medication is scarce. In this context, the present paper aims to review probiotics currently recommended by the international medical community, to evaluate the relationship between gut microbiota and various pathologies with high impact worldwide and, most importantly, to assess the literature reports concerning the ability of probiotics to influence the pharmacokinetics/pharmacodynamics of some widely used drugs, especially for those with narrow therapeutic indexes. A better understanding of the potential influence of probiotics on drug metabolism, efficacy and safety could contribute to improving therapy management, facilitating individualized therapy and updating treatment guidelines.

Immunoregulatory effects of Lactococcus lactis-derived extracellular vesicles in allergic asthma

Background

Probiotics have been shown to prevent various allergic diseases by producing extracellular vesicles (EVs). However, the role of EVs in allergic asthma has not yet been completely determined.

Methods

Gut microbial composition, mainly genera related to probiotics, was investigated in allergic asthmatic mice. Moreover, EVs were isolated from Lactococcus lactis (L. lactis, a selected bacterium) and EV proteins were identified by peptide mass fingerprinting. EV functions in immune responses were evaluated in vivo or ex vivo. Furthermore, the levels of specific IgG antibodies (an alternative marker for EV quantification) to L. lactis‐EVs were measured by ELISA in the sera of 27 asthmatic patients and 26 healthy controls.

Results

Allergic asthmatic mice showed a lower proportion of Lactococcus compared to healthy mice. L. lactis was cultured and its EVs abundantly contained pyruvate kinase. When allergic asthmatic mice were intranasally treated with EVs, airway hyperresponsiveness, eosinophil number, cytokine secretion, and mucus production were significantly decreased. Moreover, L. lactis‐EV treatment shifted immune responses from Th2 to Th1 by stimulating dendritic cells to produce IL‐12. In addition, significantly lower levels of serum specific IgG4 (but not IgG1) to L. lactis‐EVs were noted in asthmatic patients than in healthy controls. A positive correlation between the levels of EV‐specific IgG4 and FEV₁ (%), but a negative correlation between the levels of EV‐specific IgG4 and IL‐13 were observed.

Conclusion

These findings suggest that L. lactis‐EVs may have immune‐regulating effects on airway inflammation mediated by dendritic cell activation, providing a potential benefit for allergic asthma.

Modulating effects of the probiotic Lactococcus lactis on the hepatic fibrotic process induced by CCl4 in Wistar rats

Hepatic cirrhosis is a chronic disease that affects one fifth of the World's population and is the third leading cause of death in Mexico. Attempts have been made to develop treatments for this hepatic cirrhosis, which include manipulating the intestinal microbiota and thus decreasing the early inflammatory response. The microbiota is reportedly altered in patients with cirrhosis. Due to its immunomodulatory properties and its ability to survive in the gastrointestinal tract, Lactococcus lactis (L. lactis) has been used as a therapeutic measure in inflammatory disorders of the colon. The objective of the present study was to evaluate the efficacy of the L. lactis probiotic NZ9000 in preventing tetrachloromethane (CCl₄)-induced experimental hepatic fibrosis. The following 4 groups were included in the experimental stage (n=5): i) Control group; ii) L. lactis group; iii) CCl₄ group; and iv) L. lactis-CCl₄ group. For the first 2 weeks, L. lactis was orally administered to the L. lactis and L. lactis-CCl₄ groups; CCl₄ was then peritoneally administered to the lactis-CCl₄ group for a further 4 weeks (in addition to the probiotic), while the L. lactis group received the probiotic only. For the CCl₄ group, CCl₄ was administered for 4 weeks. The experimental groups were all compared with the control group and the L. lactis + CCl₄ group. Tissue samples were analyzed histologically and biochemically, and the gene expression levels of interleukin (IL)-1, IL-10 and forkhead box protein P3 (FoxP3) were determined. L. lactis decreased hepatic cirrhosis by preventing steatosis and fibrosis, and by reducing the levels of AST and ALT. Subchronic CCl₄ injury induced upregulation of the IL-1β gene in the liver, which was decreased by L. lactis. It was also found that the group treated with L. lactis showed increased expression of Foxp3 in the liver and IL-10 in the gut. These results suggested that oral administration of L. lactis may be a potential probiotic to prevent or protect against CCl₄-induced liver injury.

Oral administration of Hsp65-producing Lactococcus lactis attenuates allergic asthma in a murine model

AIMS

Allergic asthma is a chronic inflammatory lung disease characterized by a Th2-type immune response pattern. The development of nonspecific immunotherapy is one of the primary goals for the control of this disease.

METHODS AND RESULTS

In this study, we evaluated the therapeutic effects of Lactococcus lactis-producing mycobacterial heat shock protein 65 (LLHsp65) in an ovalbumin (OVA)-induced allergic asthma model. OVA-challenged BALB/c mice were orally administrated with LLHsp65 for 10 consecutive days. The results demonstrate that LLhsp65 attenuates critical features of allergic inflammation, like airway hyperresponsiveness and mucus production. Likewise, the treatment decreases the pulmonary eosinophilia and the serum level of OVA-specific IgE. In addition to deviating immune responses towards Th1-cytokine profile, increase regulatory T cells, and cytokine levels, such as IL-6 and IL-10.

CONCLUSIONS

Our results reveal that the mucosal immunotherapy of LLHsp65 significantly reduces the overall burden of airway allergic inflammation, suggesting a promising therapeutic strategy for allergic asthma treatment.

SIGNIFICANCE AND IMPACT OF THE STUDY

This research reveals new perspectives on nonspecific immunotherapy based on the delivery of recombinant proteins by lactic acid bacteria to treat of allergic disorders.

Novel Strategies for Efficient Production and Delivery of Live Biotherapeutics and Biotechnological Uses of Lactococcus lactis: The Lactic Acid Bacterium Model

Lactic acid bacteria (LAB) are traditionally used in fermentation and food preservation processes and are recognized as safe for consumption. Recently, they have attracted attention due to their health-promoting properties; many species are already widely used as probiotics for treatment or prevention of various medical conditions, including inflammatory bowel diseases, infections, and autoimmune disorders. Some LAB, especially Lactococcus lactis, have been engineered as live vehicles for delivery of DNA vaccines and for production of therapeutic biomolecules. Here, we summarize work on engineering of LAB, with emphasis on the model LAB, L. lactis. We review the various expression systems for the production of heterologous proteins in Lactococcus spp. and its use as a live delivery system of DNA vaccines and for expression of biotherapeutics using the eukaryotic cell machinery. We have included examples of molecules produced by these expression platforms and their application in clinical disorders. We also present the CRISPR-Cas approach as a novel methodology for the development and optimization of food-grade expression of useful substances, and detail methods to improve DNA delivery by LAB to the gastrointestinal tract. Finally, we discuss perspectives for the development of medical applications of recombinant LABs involving animal model studies and human clinical trials, and we touch on the main safety issues that need to be taken into account so that bioengineered versions of these generally recognized as safe organisms will be considered acceptable for medical use.

Biosensing in Smart Engineered Probiotics

Engineered microbes are exciting alternatives to current diagnostics and therapeutics. Researchers have developed a wide range of genetic tools and parts to engineer probiotic and commensal microbes. Among these tools and parts, biosensors allow the microbes to sense and record or to sense and respond to chemical and environmental signals in the body, enabling them to report on health conditions of the animal host and/or deliver therapeutics in a controlled manner. This review focuses on how biosensing is applied to engineer "smart" microbes for in vivo diagnostic, therapeutic, and biocontainment goals. Hurdles that need to be overcome when transitioning from high-throughput in vitro systems to low-throughput in vivo animal models, new technologies that can be implemented to alleviate this experimental gap, and areas where future advancements can be made to maximize the utility of biosensing for medical applications are also discussed. As technologies for engineering microbes continue to be developed, these engineered organisms will be used to address many medical challenges.

Recent Advances on Microbiota Involvement in the Pathogenesis of Autoimmunity

Autoimmune disorders derive from genetic, stochastic, and environmental factors that all together interact in genetically predisposed individuals. The impact of an imbalanced gut microbiome in the pathogenesis of autoimmunity has been suggested by an increasing amount of experimental evidence, both in animal models and humans. Several physiological mechanisms, including the establishment of immune homeostasis, are influenced by commensal microbiota in the gut. An altered microbiota composition produces effects in the gut immune system, including defective tolerance to food antigens, intestinal inflammation, and enhanced gut permeability. In particular, early findings reported differences in the intestinal microbiome of subjects affected by several autoimmune conditions, including prediabetes or overt disease compared to healthy individuals. The present review focuses on microbiota-host homeostasis, its alterations, factors that influence its composition, and putative involvement in the development of autoimmune disorders. In the light of the existing literature, future studies are necessary to clarify the role played by microbiota modifications in the processes that cause enhanced gut permeability and molecular mechanisms responsible for autoimmunity onset.

Vector Development Timeline for Mucosal Vaccination and Treatment of Disease Using Lactococcus lactis and Design Approaches of Next Generation Food Grade Plasmids

Lactococcus lactis has been used historically in fermentation and food preservation processes as it is considered safe for human consumption (GRAS—Generally Recognized As Safe). Nowadays, in addition to its wide use in the food industry, L. lactis has been used as a bioreactor for the production of molecules of medical interest, as well as vectors for DNA delivery. These applications are possible due to the development of promising genetic tools over the past few decades, such as gene expression, protein targeting systems, and vaccine plasmids. Thus, this review presents some of these genetic tools and their evolution, which allow us to envision new biotechnological and therapeutic uses of L. lactis. Constitutive and inductive expression systems will be discussed, many of which have been used successfully for heterologous production of different proteins, tested on animal models. In addition, advances in the construction of new plasmids to be used as potential DNA vaccines, delivered by this microorganism, will also be viewed. Finally, we will focus on the scene of gene expression systems known as “food-grade systems” based on inducing compounds and safe selection markers, which eliminate the need for the use of compounds harmful to humans or animal health and potential future prospects for their applications.

Exopolysaccharide from Bifidobacterium longum subsp. longum 35624™ modulates murine allergic airway responses

Interactions between the host and the microbiota are thought to significantly influence immunological tolerance mechanisms at mucosal sites. We recently described that the loss of an exopolysaccharide (EPS) from Bifidobacterium longum 35624™ eliminated its protective effects in colitis and respiratory allergy murine models. Our goal was to investigate the immune response to purified EPS from B. longum 35624, determine if it has protective effects within the lung and identify the protective mechanisms. Isolated EPS from B. longum 35624 cultures was used for in vitro, ex vivo and in vivo studies. Human monocyte-derived dendritic cells (MDDCs) were used to investigate in vitro immunological responses to EPS. Cytokine secretion, expression of surface markers and signalling pathways were examined. The ovalbumin (OVA) respiratory allergy murine model was used to evaluate the in vivo immunomodulatory potential of EPS. In addition, interleukin (IL)-10 knockout (KO) mice and anti-Toll-like receptor (TLR)-2 blocking antibody were used to examine the underlying protective mechanisms of intranasal EPS administration. Stimulation of human MDDCs with EPS resulted in IL-10 secretion, but not proinflammatory cytokines. IL-10 secretion was TLR-2-dependent. Eosinophil recruitment to the lungs was significantly decreased by EPS intranasal exposure, which was associated with decreased expression of the Th2-associated markers C-C motif chemokine 11 (CCL11), C-C chemokine receptor type 3 (CCR3), IL-4 and IL-13. TLR-2-mediated IL-10 secretion was shown to be required for the reduction in eosinophils and Th2 cytokines. EPS-treatment reduced eosinophil recruitment within the lung in a respiratory inflammation mouse model, which is both TLR-2 and IL-10 mediated. EPS can be considered as a novel molecule potentially reducing the severity of chronic eosinophil-related airway disorders.

Engineering bacteria for diagnostic and therapeutic applications

Our ability to generate bacterial strains with unique and increasingly complex functions has rapidly expanded in recent times. The capacity for DNA synthesis is increasing and costing less; new tools are being developed for fast, large-scale genetic manipulation; and more tested genetic parts are available for use, as is the knowledge of how to use them effectively. These advances promise to unlock an exciting array of 'smart' bacteria for clinical use but will also challenge scientists to better optimize preclinical testing regimes for early identification and validation of promising strains and strategies. Here, we review recent advances in the development and testing of engineered bacterial diagnostics and therapeutics. We highlight new technologies that will assist the development of more complex, robust and reliable engineered bacteria for future clinical applications, and we discuss approaches to more efficiently evaluate engineered strains throughout their preclinical development.

Lactococcus lactis As a Versatile Vehicle for Tolerogenic Immunotherapy

Genetically modified Lactococcus lactis bacteria have been engineered as a tool to deliver bioactive proteins to mucosal tissues as a means to exert both local and systemic effects. They have an excellent safety profile, the result of years of human consumption in the food industry, as well as a lack of toxicity and immunogenicity. Also, containment strategies have been developed to promote further application as clinical protein-based therapeutics. Here, we review technological advancements made to enhanced the potential of L. lactis as live biofactories and discuss some examples of tolerogenic immunotherapies mediated by mucosal drug delivery via L. lactis. Additionally, we highlight their use to induce mucosal tolerance by targeted autoantigen delivery to the intestine as an approach to reverse autoimmune type 1 diabetes.

Engineered Probiotics: Applications and Biological Containment

Bioengineered probiotics represent the next generation of whole cell-mediated biotherapeutics. Advances in synthetic biology, genome engineering, and DNA sequencing and synthesis have enabled scientists to design and develop probiotics with increased stress tolerance and the ability to target specific pathogens and their associated toxins, as well as to mediate targeted delivery of vaccines, drugs, and immunomodulators directly to host cells. Herein, we review the most significant advances in the development of this field. We discuss the critical issue of biological containment and consider the role of synthetic biology in the design and construction of the probiotics of the future.

CXCR4(+)-targeted protein nanoparticles produced in the food-grade bacterium Lactococcus lactis

AIM

Lactococcus lactis is a Gram-positive (endotoxin-free) food-grade bacteria exploited as alternative to Escherichia coli for recombinant protein production. We have explored here for the first time the ability of this platform as producer of complex, self-assembling protein materials.

MATERIALS & METHODS

Biophysical properties, cell penetrability and in vivo biodistribution upon systemic administration of tumor-targeted protein nanoparticles produced in L. lactis have been compared with the equivalent material produced in E. coli.

RESULTS

Protein nanoparticles have been efficiently produced in L. lactis, showing the desired size, internalization properties and biodistribution.

CONCLUSION

In vitro and in vivo data confirm the potential and robustness of the production platform, pointing out L. lactis as a fascinating cell factory for the biofabrication of protein materials intended for therapeutic applications.

Schistosoma mansoni Tegument (Smteg) Induces IL-10 and Modulates Experimental Airway Inflammation

BACKGROUND

Previous studies have demonstrated that S. mansoni infection and inoculation of the parasite eggs and antigens are able to modulate airways inflammation induced by OVA in mice. This modulation was associated to an enhanced production of interleukin-10 and to an increased number of regulatory T cells. The S. mansoni schistosomulum is the first stage to come into contact with the host immune system and its tegument represents the host-parasite interface. The schistosomula tegument (Smteg) has never been studied in the context of modulation of inflammatory disorders, although immune evasion mechanisms take place in this phase of infection to guarantee the persistence of the parasite in the host.

METHODOLOGY AND PRINCIPAL FINDINGS

The aim of this study was to evaluate the Smteg ability to modulate inflammation in an experimental airway inflammation model induced by OVA and to characterize the immune factors involved in this modulation. To achieve the objective, BALB/c mice were sensitized with ovalbumin (OVA) and then challenged with OVA aerosol after Smteg intraperitoneal inoculation. Protein extravasation and inflammatory cells were assessed in bronchoalveolar lavage and IgE levels were measured in serum. Additionally, lungs were excised for histopathological analyses, cytokine measurement and characterization of the cell populations. Inoculation with Smteg led to a reduction in the protein levels in bronchoalveolar lavage (BAL) and eosinophils in both BAL and lung tissue. In the lung tissue there was a reduction in inflammatory cells and collagen deposition as well as in IL-5, IL-13, IL-25 and CCL11 levels. Additionally, a decrease in specific anti-OVA IgE levels was observed. The reduction observed in these inflammatory parameters was associated with increased levels of IL-10 in lung tissues. Furthermore, Smteg/asthma mice showed high percentage of CD11b+F4/80+IL-10+ and CD11c+CD11b+IL-10+ cells in lungs.

CONCLUSION

Taken together, these findings demonstrate that S. mansoni schistosomula tegument can modulates experimental airway inflammation.

Interleukin-10 modulates pulmonary neutrophilic inflammation induced by cigarette smoke exposure

AIM OF THE STUDY

Interleukin (IL)-10 is an anti-inflammatory cytokine, but its role in cigarette smoke (CS)-induced inflammation and chronic obstructive pulmonary disease (COPD) has not been fully elucidated. The purpose of this study was to investigate the effect of IL-10 deficiency on CS-induced pulmonary inflammation in mice in vivo and in vitro.

MATERIALS AND METHODS

IL-10-deficient and wild-type control mice with a C57BL6/J genetic background were exposed to CS, and inflammatory cells in bronchoalveolar lavage fluid (BALF) and mRNA of cytokines in lung were evaluated with enzyme-linked immunosorbent assay (ELISA) and reverse transcription polymerase chain reaction (RT-PCR).

RESULTS

During 12 days of daily CS exposure to wild-type mice, neutrophil counts in BAL fluid and tumor necrosis factor (TNF)-α mRNA expression were increased, peaked at day 8, and then declined on day 12 when the level of IL-10 reached its peak. In IL-10-deficient mice, neutrophil recruitment and TNF-α mRNA levels induced by CS exposure were significantly greater than those in wild-type mice. Keratinocyte-derived chemokine (KC; murine ortholog of human CXCL8) and granulocyte macrophage colony-stimulating factor (GM-CSF) mRNA levels or matrix metalloproteinase(MMP)-9 protein levels were not correlated with neutrophil count.

CONCLUSIONS

IL-10 had a modulatory effect on CS-induced pulmonary neutrophilic inflammation and TNF-α expression in mice in vivo and therefore appears to be an important endogenous suppressor of airway neutrophilic inflammation.

Recombinant Lactococcus lactis can make the difference in antigen-specific immune tolerance induction, the Type 1 Diabetes case

Especially in western civilizations, immune diseases that are driven by innocuous (auto- or allo-) antigens are gradually evolving to become pandemic threats. A particularly poignant example is type 1 diabetes, where young children are confronted with the perspective and consequences of total pancreatic β-cell destruction. Along these disquieting observations we find ourselves equipped with impressively accumulating molecular immunological knowledge on the ins and outs of these pathologies. Often, however, it is difficult to translate this wealth into efficacious medicines. The molecular understanding, the concept of oral tolerance induction, the benefit of using recombinant Lactococcus lactis therein and recent openings towards their clinical use may well enable turning all colors to their appropriate fields on this Rubik's cube.

Interleukins for the paediatric pulmonologist

Interleukins are critical immune modulators and since their first description in 1977, there has been a steady increase in the recognition of their roles in many paediatric respiratory diseases. This basic and clinical knowledge is now maturing into both approved and investigational therapies aimed at blocking or modifying the interleukin response. The purpose of this review is to bring up to date what is known about interleukin function in paediatric pulmonology, focusing on nine important lung conditions. This is followed by summaries about 18 interleukins which have been associated with these paediatric pulmonary conditions. Throughout, emphasis is placed on where interventions have been tested. Over the next several years, it is likely that many more treatments based on interleukin biology and function will become available and understanding the basis for these therapies will allow the practicing paediatric pulmonologist to take appropriate advantage of them.

Mucosal targeting of therapeutic molecules using genetically modified lactic acid bacteria: an update

Lactic acid bacteria (LAB) represent a heterogeneous group of microorganisms naturally present in many foods and those have proved to be effective mucosal delivery vectors. Moreover, some specific strains of LAB exert beneficial properties (known as probiotic effect) on both human and animal health. Although probiotic effects are strain-specific traits, it is theoretically possible, using genetic engineering techniques, to design strains that can exert a variety of beneficial properties. During the two past decades, a large variety of therapeutic molecules has been successfully expressed in LAB, and although this field has been largely reviewed in recent years, approximately 20 new publications appear each year. Thus, the aim of this minireview is not to extensively assess the entire literature but to update progress made within the last 2 years regarding the use of the model LAB Lactococcus lactis and certain species of lactobacilli as live recombinant vectors for the development of new safe mucosal vaccines.

Nonallergen-specific treatments for food allergy

PURPOSE OF REVIEW

This review summarizes recent reports on nonallergen-specific therapies for food allergy. These therapies are especially appealing for food allergy because unlike allergen-specific immunotherapy, they would allow the treatment of multiple food allergies in a single patient with one therapy.

RECENT FINDINGS

Chinese herbal therapy, anti-IgE, probiotics, engineered lactic acid bacteria, and helminth therapy are all examples of allergen nonspecific therapies that have been investigated in recent years. Although some have only been studied in animal models of food allergy, some are undergoing rigorous, human clinical trials.

SUMMARY

Increasing amounts of research are examining the efficacy and safety of nonallergen-specific therapies for food allergy. There is hope that clinicians will have effective treatments either as an alternative or as an adjunct to immunotherapy.

Developments in the field of allergy in 2010 through the eyes of Clinical and Experimental Allergy

In 2010 over 200 articles were published in Clinical and Experimental Allergy including editorials, reviews, opinion articles, letters, book reviews and of course at the heart of the journal, papers containing original data which have moved the field of allergy forward on a number of fronts. For the third year running the editors felt it would be of value to summarize the key messages contained in these papers as a snapshot of where the cutting edge of research into allergic disease is leading. We have broadly followed the sections of the journal, although this year the mechanistic articles are grouped together and the studies involving experimental models of disease are discussed throughout the paper. In the field of asthma and rhinitis phenotypes and biomarkers continue to a major pre-occupation of our authors. There is continued interest in mechanisms of inflammation and disordered lung function with the mouse model of asthma continuing to offer new insights. There is also a steady flow of papers investigating new therapies, including those derived from plants and herbs, although many are mechanistic with too few high quality clinical trials. The mechanisms involved in allergic disease are well covered with many strong papers using clinical material to ask relevant questions. Pro-pre and snybiotics continue to be of major interest to our authors and this remains a controversial and complicated field. The discipline of epidemiology has retained its interest in risk factors for the development of allergic disease with a view to refining and debating the reasons for the allergy epidemic. There is continued interest in the relationship between helminthic disease and allergy with a new twist in 2010 involving studies using infection with helminths as a potential treatment. The genetics of allergic disease continues to be very productive, although the field has moved on from only investigating single nucleotide polymorphisms of candidate genes to Genome Wide Association Studies and an increasing and welcome emphasis on gene-environment interactions. In the field of clinical allergy there is steady flow of papers describing patterns of drug allergy with renewed interest in reactions to contrast media, but food allergy is the major area of interest in this section of the journal. Lastly in the field of allergens there is a growing interest in the role of component resolved diagnosis in improving the diagnosis and management of allergic disease. Another excellent year, full of fascinating and high quality work, which the journal has been proud to bring to the allergy community.

Tight controlled expression and secretion of Lactobacillus brevis SlpA in Lactococcus lactis

Prokaryotes commonly present outer cell wall structures composed of a crystalline array of proteinaceous subunits, known as surface layers (S-layers). The ORF encoding the S-layer protein (SlpA) of Lactobacillus brevis was cloned into Lactococcus lactis under the transcriptional control of the xylose-inducible expression system (XIES). SlpA was secreted into the extracellular medium, as determined by immunoblotting, and assays on the kinetics of SlpA production revealed that repression of the system with glucose did not require the depletion of xylose from the medium that allows transitory ORF expression. The successful use of XIES to express S-layer proteins in the versatile and generally recognized as safe species L. lactis opens new possibilities for an efficient production and isolation of SlpA S-layer protein for its various applications in biotechnology and importantly as an antigen-carrying vehicle.

Potential Application of Probiotics in the Prevention and Treatment of Inflammatory Bowel Diseases

Lactic acid bacteria (LAB) represent a heterogeneous group of microorganisms that are naturally present in many foods and possess a wide range of therapeutic properties. The aim of this paper is to present an overview of the current expanding knowledge of the mechanisms by which LAB and other probiotic microorganisms participate in the prevention and treatment of inflammatory bowel diseases. These include changes in the gut microbiota, stimulation of the host immune responses, and reduction of the oxidative stress due to their antioxidant properties. A brief overview of the uses of genetically engineered LAB that produce either antioxidant enzymes (such as catalase and superoxide dismutase) or anti-inflammatory cytokines (such as IL-10) will also be discussed. This paper will show that probiotics should be considered in treatment protocols of IBD since they provide many beneficial effects and can enhance the effectiveness of traditional used medicines.

Importance of IL-10 modulation by probiotic microorganisms in gastrointestinal inflammatory diseases

Lactic acid bacteria (LAB) represent a heterogeneous group of microorganisms that are naturally present in many foods and possess a wide range of therapeutic properties. The aim of this paper is to present an overview of the current expanding knowledge of one of the mechanisms by which LAB and other probiotic microorganisms participate in the prevention and treatment of gastrointestinal inflammatory disease through their immune-modulating properties. A special emphasis will be placed on the critical role of the anti-inflammatory cytokine IL-10, and a brief overview of the uses of genetically engineered LAB that produce this important immune response mediator will also be discussed. Thus, this paper will demonstrate the critical role that IL-10 plays in gastrointestinal inflammatory diseases and how probiotics could be used in their treatment.