Immunomodulation with microbial vaccines to prevent type 1 diabetes mellitus

Paeoniflorin protects NOD mice from T1D through regulating gut microbiota and TLR4 mediated myD88/TRIF pathway

This study aimed to explore the effect of PF in regulating the progression of T1D through regulating gut microbiota and inhibiting TLR4-myD88/TRIF pathway. T1D mouse models were established and received PF treatment through intraperitoneal injection. The glucose, sugar tolerance, the incidence of T1D and H&E staining were detected to verify the effect of PF on T1D. Meanwhile, the changes of gut microbiota and the permeability of intestines in mice were also measured. On parallel, the number and function of immune cells were detected by Flow Cytometry. The expressions of ZO-1, ZO-2 and TLR4-myD88/TRIF pathway related proteins were detected by western blotting. Mice received PF treatment had decreased incidence of T1D and inflammatory infiltration in islet tissues compared with those received PBS treatment. In addition to that, PF treated mice had increased Sutterella species and decreased intestinal permeability, in which the decreased ratio of Th1/Th17 and increased Treg cells were also identified. The expression of TLR4-myD88/TRIF pathway was also suppressed in response to PF treatment. Moreover, further treatment with TLR4 agonist, LPS, could reverse the effect of PF on T1D mice. PF can suppress the TLR4 mediated myD88/TRIF pathway to change the distribution of gut microbiota, so as to protect NOD mice from T1D.

Vaccine for Diabetes-Where Do We Stand?

Diabetes is an endocrinological disorder with a rapidly increasing number of patients globally. Over the last few years, the alarming status of diabetes has become a pivotal factor pertaining to morbidity and mortality among the youth as well as middle-aged people. Current developments in our understanding related to autoimmune responses leading to diabetes have developed a cause for concern in the prospective usage of immunomodulatory agents to prevent diabetes. The mechanism of action of vaccines varies greatly, such as removing autoreactive T cells and inhibiting the interactions between immune cells. Currently, most developed diabetes vaccines have been tested in animal models, while only a few human trials have been completed with positive outcomes. In this review, we investigate the undergoing clinical trial studies for the development of a prototype diabetes vaccine.

The Effects of Single Strains and Mixtures of Probiotic Bacteria on Immune Profile in Liver, Spleen, and Peripheral Blood

Probiotic bacteria have potential use as immunomodulators but comparative data on their immunological effects are very limited. The aim of this study was to characterize the effect of oral administration of probiotic strains, alone or as mixtures, on systemic and organ-specific immune responses. For this purpose, healthy C57BL/6 mice were perorally administered probiotics for 3 weeks. A total of five common probiotic strains, Lactobacillus rhamnosus species GG (LGG) and LC705, Bifidobacterium breve 99 (Bb99), Propionibacterium freudenreichii Shermanii JS (PJS), and Escherichia coli Nissle 1917 (EcN), and two of their mixtures, were tested. Livers, spleens, and blood were collected for investigation. A number of five treatments increased the abundance of the natural killer (NK) cells. Bb99 had the most prominent effect on hepatic NK cells (20.0 ± 1.8%). LGG (liver: 5.8 ± 1.0%; spleen: 1.6 ± 0.4%), Bb99 (liver: 13.9 ± 4.3%; spleen: 10.3 ± 3.7%), and EcN (liver: 8.5 ± 3.2%; spleen: 1.0 ± 0.2%) increased the percentage of both the hepatic and splenic T-helper 17 cells. Moreover, LGG (85.5 ± 3.0%) and EcN (89.6 ± 1.2%) increased the percentage of splenic regulatory T-cells. The tested mixtures of the probiotics had different immunological effects from their individual components on cell-mediated responses and cytokine production. In conclusion, our results confirm that the immunomodulatory potential of the probiotics is strain- and organ/tissue-specific, and the effects of probiotic mixtures cannot be predicted based on their single constituents.

Impact of Prebiotics and Synbiotics Administered in ovo on the Immune Response against Experimental Antigens in Chicken Broilers

Simple Summary

The immune system of chickens matures in the course of embryonic development. Early in ovo supplementation with bioactive substances leads to the long-term maintenance of a high level of intestine bifidobacteria, reduces the number of detrimental microorganisms in the gut, modulates the central and peripheral lymphatic organ development in broilers, and stimulates gut-associated lymphoid tissues (GALT) development after hatching. In this investigation, we studied whether the early in ovo application (at the 12th day of embryo incubation) of selected bioactives (prebiotics and synbiotics) influences the humoral immune response against experimental antigens, and the delayed-type hypersensitivity (DTH) skin reaction to experimental mitogen. This study demonstrated that the in ovo application of bioactives did not significantly influence the humoral immune response against T-dependent and T-independent model antigens. Prebiotics in chickens immunized with T-dependent antigen (SRBC) protected them from a retarded rise of the IgG concentration. Bioactives reduced the mortality of birds, markedly with inulin (−6.4%), and the DTH reaction to phytohemagglutinin on the 7^th and 21^st day after hatching.

Abstract

The effect of the in ovo application of selected prebiotics and synbiotics on the humoral immune response against T-dependent (SRBC) and T-independent (dextran) antigens and delayed-type hypersensitivity (DTH) to phytohemagglutinin was studied. On the 12th day of incubation, 800 eggs (Ross 308) were divided into five groups and injected into the egg air chamber with prebiotic inulin (Pre1), Bi²tos (Pre2), a synbiotic composed of inulin and Lactococcus lactis subsp. lactis IBB SL1 (Syn1), a synbiotic composed of Bi²tos and L. lactis subsp. cremoris IBB SC1 (Syn2), and physiological saline (control group; C). The chickens were immunized twice at the 7th and 21st day of life with SRBC and dextran. A DTH test was performed on the 7th, 21st, and 35th day. The application of prebiotics and synbiotics had no significant effect on the humoral immune response. SRBC-immunized in ovo Pre1- and Pre2-treated chickens showed significantly higher serum IgG levels than the control. A significant effect on the DTH reaction was detected on the 7th (Pre1 < C) and 21st (Pre2 > Syn2) day. However; Bi²tos may transiently stimulate the cellular immune response on the 21st day. It may be concluded that the application of inulin in an egg air chamber on the 12th day of incubation may stimulate the secondary immune response. The inulin-treated group exhibited a lower mortality rate than the control group.

Neonatal Bacillus Calmette-Guérin vaccination alleviates lipopolysaccharide-induced neurobehavioral impairments and neuroinflammation in adult mice

The Bacillus Calmette-Guérin (BCG) vaccine is routinely administered to human neonates worldwide. BCG has recently been identified as a neuroprotective immune mediator in several neuropathological conditions, exerting neuroprotection in a mouse model of Parkinson's disease and slowing the progression of clinically isolated syndrome in patients with multiple sclerosis. The immune system is significantly involved in brain development, and several types of neonatal immune activations exert influences on the brain and behavior following a secondary immune challenge in adulthood. However, whether the neonatal BCG vaccination affects the brain in adulthood remains to be elucidated. In the present study, newborn C57BL/6 mice were injected subcutaneously with BCG (10⁵ colony forming units) or phosphate-buffered saline (PBS). A total of 12 weeks later, the mice were injected intraperitoneally with 330 µg/kg lipopolysaccharide (LPS) or PBS. The present study reported that the neonatal BCG vaccination alleviated sickness, anxiety and depression-like behavior, lessened the impairments in hippocampal cell proliferation and downregulated the proinflammatory responses in the serum and brain that were induced by the adult LPS challenge. However, BCG vaccination alone had no evident influence on the brain and behavior in adulthood. In conclusion, the neonatal BCG vaccination alleviated the neurobehavioral impairments and neuroinflammation induced by LPS exposure in adult mice, suggesting a potential neuroprotective role of the neonatal BCG vaccination in adulthood.

Advax™, a novel microcrystalline polysaccharide particle engineered from delta inulin, provides robust adjuvant potency together with tolerability and safety

There is an ongoing need for new adjuvants to facilitate development of vaccines against HIV, tuberculosis, malaria and cancer, amongst many others. Unfortunately, the most potent adjuvants are often associated with toxicity and safety issues. Inulin, a plant-derived polysaccharide, has no immunological activity in its native soluble form but when crystallized into a stable microcrystalline particulate from (delta inulin) acquires potent adjuvant activity. Delta inulin has been shown to enhance humoral and cellular immune responses against a broad range of co-administered viral, bacterial, parasitic and toxin antigens. Inulin normally crystallizes as large heterogeneous particles with a broad size distribution and variable solubility temperatures. To ensure reproducible delta inulin particles with a consistent size distribution and temperature of solubility, a current Good Manufacturing Practice (cGMP) process was designed to produce Advax™ adjuvant. In its cCMP form, Advax™ adjuvant has proved successful in human trials of vaccines against seasonal and pandemic influenza, hepatitis B and insect sting anaphylaxis, enhancing antibody and T-cell responses while being safe and well tolerated. Advax™ adjuvant represents a novel human adjuvant that enhances both humoral and cellular immunity. This review describes the discovery and development of Advax™ adjuvant and research into its unique mechanism of action.

CD8α¯ DC is the major DC subset which mediates inhibition of allergic responses by Schistosoma infection

Our and others' previous studies have shown that Schistosoma japonicum (SJ) infection can inhibit allergic reactions. We recently reported that DCs played an important role in SJ infection-mediated inhibition of allergy, which was associated with enhanced IL-10 and T regulatory cell responses. Here, we further compared the role of CD8α(+) DC and CD8α(-) DC subsets for the inhibitory effect. We sorted CD8α(+) DC (SJCD8α(+) DC) and CD8α(-) DC (SJCD8α(-) DC) from SJ-infected mice and tested their ability to modulate allergic responses in vivo. The data showed that the adoptive transfer of SJCD8α(-) DC was much more efficient than SJCD8α(+) DC for the suppression of allergic airway eosinophilia, mucus overproduction, antigen-specific IgE responses, and Th2 cytokines (IL-4 and IL-5). More importantly, we found that the transfer of SJCD8α(-) DC, but not SJCD8α(+) DC, significantly increased IL-10 and TGF-β production following OVA exposure. As control, the transfer of DC subsets from naïve mice had no significant effect on allergic inflammation. In addition, SJCD8α-DC expressed significantly higher IL-10 but lower IL-12, CD80 and CD86 than SJCD8α(+) DC, fitting a tolerogenic phenotype. The results suggest that CD8α(-) DC is the predominant DC subset which is involved in the parasitic infection-mediated inhibition of allergic inflammation and possibly through enhancing immunomodulatory cytokine (IL-10 and TGF-β) production.

Oral administration of recombinant Lactococcus lactis expressing HSP65 and tandemly repeated P277 reduces the incidence of type I diabetes in non-obese diabetic mice

Diabetes mellitus type 1 (DM1) is an autoimmune disease that gradually destroys insulin-producing beta-cells. We have previously reported that mucosal administration of fusion protein of HSP65 with tandem repeats of P277 (HSP65-6P277) can reduce the onset of DM1 in non-obese diabetic (NOD) mice. To deliver large amounts of the fusion protein and to enhance long-term immune tolerance effects, in the present study, we investigated the efficacy of using orally administrated L. lactis expressing HSP65-6P277 to reduce the incidence of DM1 in NOD mice. L. lactis strain NZ9000 was engineered to express HSP65-6P277 either constitutively or by nisin induction. After immunization via gavage with the recombinant L. lactis strains to groups of 4-week old female NOD mice for 36 weeks, we observed that oral administration of recombinant L. Lactis resulted in the prevention of hyperglycemia, improved glucose tolerance and reduced insulitis. Immunologic analysis showed that treatment with recombinant L. lactis induced HSP65- and P277- specific T cell immuno-tolerance, as well as antigen-specific proliferation of splenocytes. The results revealed that the DM1-preventing function was in part caused by a reduction in the pro-inflammatory cytokine IFN-γ and an increase in the anti-inflammatory cytokine IL-10. Orally administered recombinant L. lactis delivering HSP65-6P277 may be an effective therapeutic approach in preventing DM1.

Early immunotherapy using autologous adult stem cells reversed the effect of anti-pancreatic islets in recently diagnosed type 1 diabetes mellitus: preliminary results

BACKGROUND

Bone marrow stem cell treatment has been proven a promising therapeutic strategy and showed significant results given the strong immune modulating properties. We have investigated the safety and efficacy of autologous bone marrow stem cell transplantation through liver puncture in two patients with recently diagnosed type 1 diabetes mellitus.

MATERIAL AND METHODS

The procedure was approved by the Institutional Ethics Committee. In 2011, in three young patients, type 1 diabetes mellitus diagnosis was confirmed, with the presence of positive antibodies and ketoacidosis. Two patients was treated with autologous bone marrow stem cell stimulated with filgrastim and transplantation, through liver puncture, as immune modulators. One patients was treated with conventional treatment and participate in this experiment as a control group. The families of the patients signed the informed consent. No specific statistical analysis was performed. The patients had less than 8 years old, diagnosis of type 1 diabetes for less than 60 days, body mass index less than 22 kg/m2, normal complete blood count, coagulation and renal function, no lesions in target organs, glycosylated hemoglobin (HbA1c) level less than 13.70%, c-peptide level less than 0.67 ng/ml, positive results of Islets Cells Antibody (ICA), Glutamic Acid Decarboxylase (GAD) and insulin antibody.

RESULTS

In two patients treated, the follow up at 12 months showed negative value in ICA, GAD and anti insulin antibody levels, with an increased levels of c peptide and decreased levels of blood glucose and HbA1c.

CONCLUSIONS

Treatment with autologous bone marrow stem cells is easy and effective as it reversed the production and effect of anti pancreatic islet antibody and significantly resulted in an increased c-peptide concentration.

The microbiology of human hygiene and its impact on type 1 diabetes

The incidence of type 1 diabetes (T1D), as with several other autoimmune diseases and conditions, began to notably rise in the latter half of the last century. Most cases of T1D are not solely attributable to genetics and therefore, environmental influences are proposed to account for the difference. Humans live today in general under much more hygienic conditions than their ancestors. Although human enteroviruses (HEV) have been strongly implicated as causative environmental agents of T1D, recent work has shown that the bacterial genera in the gut of diabetics compared with non-diabetics, can vary significantly. Here, we consider these data in light of our non-hygienic human past in order to discuss a possible relationship between the resident bacterial biome and acute infectious events by HEV, suggesting how this may have influenced T1D incidences in the past and the risk for developing T1D today.

Human cord blood stem cells and the journey to a cure for type 1 diabetes

Umbilical cord blood contains several types of stem cells that are of interest to a wide range of disciplines in regenerative medicine. The translational potential to the clinical applications of cord blood stem cells has increased enormously in recent years, mainly because of its advantages including no risk to the donor, no ethical issues, low risk of graft-versus-host disease (GVHD) and rapid availability. Type 1 diabetes (T1D) is an autoimmune disease caused by an autoimmune destruction of pancreatic islet β cells. Understanding the nature and function of cord blood stem cells is an exciting challenge that might set the stage for new approaches to the treatment of T1D. Here, we review progress in this field and draw conclusions for the development of future therapeutics in T1D. New insights are provided on a unique type of cord blood-derived multipotent stem cells (CB-SC), including the molecular mechanisms underlying immune modulation by CB-SC, protection of β-cell mass, and promotion of islet β-cell neogenesis.