Enhancement of IL-10 bioactivity using an IL-10 peptide-based vaccine exacerbates Leishmania major infection and improves airway inflammation in mice

Protective Humoral Immune Response Induced by Recombinant Virus-like Particle Vaccine Expressing Leishmania donovani Surface Antigen

To date, Leishmania spp. vaccine studies have mainly focused on cellular immunity induction, which plays a crucial role in host protection. In contrast, vaccine-induced humoral immunity is largely neglected. Virus-like particle (VLP) vaccines generated using the baculovirus expression system are well-known inducers of humoral immunity and would serve as a suitable platform for evaluating humoral immunity-mediated protection against visceral Leishmaniasis. In this study, we investigated the humoral immunity evoked through VLPs expressing the L. donovani promastigote surface antigen (PSA-VLPs) and assessed their contribution to protection in mice. PSA-VLPs vaccines were generated using the baculovirus expression system and used for mouse immunizations. Mice were intramuscularly immunized twice with PSA-VLPs and challenged with L. donovani to confirm vaccine-induced protective immunity. PSA-VLP immunization elicited parasite-specific antibody responses in the sera of mice, which were induced in a dose-dependent manner. B cell, germinal center B cell, and memory B cell responses in the spleen were found to be higher in vaccinated mice compared to unimmunized controls. PSA-VLP immunization diminished the production of pro-inflammatory cytokines IFN-γ and IL-6 in the liver. Overall, the PSA-VLPs conferred protection against L. donovani challenge infection by reducing the total parasite burden within the internal organs. These results suggest that PSA-VLPs induced protective immunity against the L. donovani challenge infection.

Development of nano-carriers for Leishmania vaccine delivery

Introduction: Leishmaniasis is a neglected tropical infection caused by several species of intracellular protozoan parasites of the genus Leishmania. It is strongly believed that the development of vaccines is the most appropriate approach to control leishmaniasis. However, there is no vaccine available yet and the lack of an appropriate adjuvant delivery system is the main reason.Areas covered: Adjuvants are the utmost important part of a vaccine, to induce the immune response in the right direction. Limitations and drawbacks of conventional adjuvants have been necessitated the development of novel particulate delivery systems as adjuvants to obtain desirable protection against infectious diseases such as leishmaniasis. This review focused on particulate adjuvants especially nanoparticles that are in use to develop vaccines against leishmaniasis. The list of adjuvants includes generally lipids-, polymers-, or mineral-based delivery systems that target antigens specifically to the site of action within the host's body and enhance immune responses.Expert opinion: Over the past few years, there has been an increasing interest in developing particulate adjuvants as alternatives to immunostimulatory types. The composition of nano-carriers and particularly the physicochemical properties of nanoparticles have great potential to overcome challenges posed to leishmaniasis vaccine developments.

A Comprehensive Review and Update on the Pathogenesis of Inflammatory Bowel Disease

Inflammatory bowel disease (IBD) is a chronic and life-threating inflammatory disease of gastroenteric tissue characterized by episodes of intestinal inflammation. The pathogenesis of IBD is complex. Recent studies have greatly improved our knowledge of the pathophysiology of IBD, leading to great advances in the treatment as well as diagnosis of IBD. In this review, we have systemically reviewed the pathogenesis of IBD and highlighted recent advances in host genetic factors, gut microbiota, and environmental factors and, especially, in abnormal innate and adaptive immune responses and their interactions, which may hold the keys to identify novel predictive or prognostic biomarkers and develop new therapies.

Protease-Activated Receptor 2 Agonist as Adjuvant: Augmenting Development of Protective Memory CD8 T Cell Responses Induced by Influenza Virosomes

Protease-activated receptor 2 (PAR-2) is expressed in various tissues, including lung, and when activated, promotes inflammation, differentiation, and migration of dendritic cells. We found that combining influenza virosomes containing hemagglutinin and neuraminidase with a PAR-2 agonist peptide (PAR-2AP) in an intranasal prime boost approach increased survival of mice challenged weeks later with lethal influenza virus over that by virosome or PAR-2AP prime boost alone. No weight loss occurred from influenza challenge after virosome-plus-PAR-2AP prime boost compared with either virosomes or PAR-2AP alone. Thus, virosomes plus PAR-2AP prevented morbidity as well as mortality. Through adoptive transfer, CD8⁺ lung T cells but not CD4⁺ T cells from virosomes plus PAR-2AP-primed mice protected from lethal influenza virus challenge and enhanced survival with less weight loss and faster recovery. Virosome-plus-PAR-2AP prime boost resulted in greater percentages of T effector memory phenotype cells (Tem) in lung, and higher frequencies of CD8 Tem and T central memory cells displayed effector functions in response to virus challenge in vivo. Virosome-plus-PAR-2AP prime boost also resulted in greater percentages of Ag-specific CD8⁺ T cells, both Tem and T central memory cells, in lungs of animals subsequently challenged with live influenza virus. Our findings indicate that PAR-2AP, a short peptide, may be a new and useful mucosal adjuvant.

SplitCore Technology Allows Efficient Production of Virus-Like Particles Presenting a Receptor-Contacting Epitope of Human IgE

Immunoglobulin E (IgE) plays a central role in type I hypersensitivity including allergy and asthma. Novel treatment strategy envisages development of a therapeutic vaccine designed to elicit autologous blocking antibodies against the IgE. We sought to develop an IgE-epitope antigen that induces antibodies against a receptor-contacting epitope on human IgE molecule. We designed the VLP immunogens which utilize hepatitis B virus core protein (HBcAg) as a carrier, and present arrays of the receptor-contacting epitopes of the human IgE on their surfaces. FG loop from the IgE domain Cε3 was engineered into the HBcAg. Two constructs explore a well-established approach of insertion into a main immunodominant region of the HBcAg. Third construct is different in that the carrier is produced in a form of an assembly of two polypeptide chains which upon expression remain associated in a stable VLP-forming subunit (SplitCore technology). No VLPs were isolated from E.coli expressing the IgE-epitope antigens with contiguous sequences. On the contrary, the SplitCore antigen carrying the FG loop efficiently formed the VLPs. Immunization of mice with the VLPs presenting receptor-contacting epitope of the IgE elicited antibodies recognizing the human IgE in ELISA.

Vaccinated C57BL/6 mice develop protective and memory T cell responses to Coccidioides posadasii infection in the absence of interleukin-10

High concentrations of lung tissue-associated interleukin-10 (IL-10), an anti-inflammatory and immunosuppressive cytokine, correlate with susceptibility of mice to Coccidioides spp. infection. In this study, we found that macrophages, dendritic cells, neutrophils, and both CD8(+) and CD4(+) T cells recruited to Coccidioides posadasii-infected lungs of nonvaccinated and vaccinated mice contributed to the production of IL-10. The major IL-10-producing leukocytes were CD8(+) T cells, neutrophils, and macrophages in lungs of nonvaccinated mice, while both Foxp3(+) and Foxp3(-) subsets of IL-10(+) CD4(+) T cells were significantly elevated in vaccinated mice. Profiles of the recruited leukocytes in lungs revealed that only CD4(+) T cells were significantly increased in IL-10(-/-) knockout mice compared to their wild-type counterparts. Furthermore, ex vivo recall assays showed that CD4(+) T cells isolated from vaccinated IL-10(-/-) mice compared to vaccinated wild-type mice produced significantly higher amounts of IL-2, gamma interferon (IFN-γ), IL-4, IL-6, and IL-17A in the presence of a coccidioidal antigen, indicating that IL-10 suppresses Th1, Th2, and Th17 immunity to Coccidioides infection. Analysis of absolute numbers of CD44(+) CD62L(-) CD4(+) T effector memory T cells (TEM) and IFN-γ- and IL-17A-producing CD4(+) T cells in the lungs of Coccidioides-infected mice correlated with better fungal clearance in nonvaccinated IL-10(-/-) mice than in nonvaccinated wild-type mice. Our results suggest that IL-10 suppresses CD4(+) T-cell immunity in nonvaccinated mice during Coccidioides infection but does not impede the development of a memory response nor exacerbate immunopathology of vaccinated mice over at least a 4-month period after the last immunization.

An IL-17 peptide-based and virus-like particle vaccine enhances the bioactivity of IL-17 in vitro and in vivo

AIMS

To develop an IL-17 peptide-based virus-like particle vaccine that elicits autoantibodies to IL-17 and to evaluate the effects of the vaccine in mice with experimental colitis.

MATERIALS & METHODS

Recombinant IL-17 vaccines were constructed by inserting selected peptides derived from mouse IL-17 into the carrier protein, hepatitis B core antigen, using molecular engineering methods. To evaluate the in vivo effects of the vaccine, mice with 2,4,6-trinitrobenzene sulfonic acid-induced chronic colitis were injected three times with the vaccine, carrier or saline after the second delivery of 2,4,6-trinitrobenzene sulfonic acid. Colon inflammation and fibrosis were evaluated by histological examination. Serum IL-17-specific IgG and colon-tissue cytokine levels were measured by ELISA. In vitro inhibition tests of sera from vaccine-immunized mice were performed using IL-17-induced IL-6 production by NIH 3T3 cells and IL-17-induced TNF production by macrophages.

RESULTS

Immunization with the vaccine without the use of adjuvants induced high-titered and long-lasting antibodies to IL-17. Unexpectedly, vaccinated mice exhibited increases in colon inflammation, collagen deposition, levels of TNF and IL-17 cytokines compared with carrier and saline groups. Furthermore, in vitro study revealed that serum IL-17-specific IgG from vaccine-immunized mice significantly enhanced IL-17-induced IL-6 production and IL-17-induced TNF production dose-dependently.

CONCLUSION

The IL-17 peptide-based vaccine enhances the bioactivity of IL-17 in vitro and in vivo, providing a potential immunotherapy for treatment of diseases associated with insufficient IL-17 production, such as hyper-IgE syndrome.

Targeting IL-23 by employing a p40 peptide-based vaccine ameliorates murine allergic skin and airway inflammation

BACKGROUND

Studies have found that the IL-23/Th17 pathway plays an important role in the pathogenesis of atopic dermatitis (AD) and severe and steroid-resistant asthma. Targeting IL-23/Th17 pathway with monoclonal antibodies (mAb) has been successful in the reduction of skin and airway inflammation in animal models. However, the mAb has a short half-life, requiring repeated administrations. For the long-term suppression of IL-23/Th17 pathway, we have previously developed an IL-23p40 peptide-based virus-like particle vaccine, which induces long-lasting autoantibodies to IL-23.

OBJECTIVE

We sought to evaluate the effects of this IL-23p40 peptide-based vaccine on the down-regulation of allergic skin and airway inflammation in mice.

METHODS

Mice were subcutaneously injected three times with the IL-23p40 vaccine, or the vaccine carrier protein or saline as controls. Two weeks later, mice were epicutaneously sensitized with ovalbumin four times at a 2-week interval. One week after the final sensitization, mice were nasally administrated with ovalbumin daily for 3 days. One day later, bronchoalveolar lavage fluids (BALF), sera, lung and skin tissues were obtained and analysed.

RESULTS

Mice immunized with the vaccine produced high levels of IgG antibodies to IL-23, p40 and IL-12 that in vitro inhibited IL-23-dependent IL-17 production. The numbers of total cells, neutrophils, and eosinophils in BALF were significantly reduced in the vaccine group, compared with controls. The levels of IL-13, IL-5, IL-23 and, IL-17 in BALF and levels of serum ovalbumin-specific IgE, IgG1, and total IgE were also significantly decreased. Histological analysis showed less inflammation of the lung and skin tissues in the vaccine group, compared with controls.

CONCLUSION AND CLINICAL RELEVANCE

Administration of an IL-23p40 peptide-based vaccine down-regulates allergic skin and airway inflammation, suggesting that this strategy may be a potential therapeutic approach in the treatment of AD and asthma.

Interleukin-10: an anti-inflammatory marker to target atherosclerotic lesions via PEGylated liposomes

Atherosclerosis (AS) causes cardiovascular disease, which leads to fatal clinical end points like myocardial infarction or stroke, the most prevalent causes of death in developed countries. An early, noninvasive method of detection and diagnosis of atherosclerotic lesions is necessary to prevent and treat these clinical end points. Working toward this goal, we examined recombinant interleukin-10 (IL-10), stealth liposomes with nanocargo potency for NMRI relevant contrast agents, and IL-10 coupled to stealth liposomes in an ApoE-deficient mouse model using confocal laser-scanning microscopy (CLSM). Through ex vivo incubation and imaging with CLSM, we showed that fluorescently labeled IL-10 is internalized by AS plaques, and a low signal is detected in both the less injured aortic surfaces and the arteries of wild-type mice. In vivo experiments included intravenous injections of (i) fluorescent IL-10, (ii) IL-10 targeted carboxyfluorescin (CF-) labeled stealth liposomes, and (iii) untargeted CF-labeled stealth liposomes. Twenty-four hours after injection the arteries were dissected and imaged ex vivo. Compared to free IL-10, we observed a markedly stronger fluorescence intensity with IL-10 targeted liposomes at AS plaque regions. Moreover, untargeted CF-labeled liposomes showed only weak, unspecific binding. Neither free IL-10 nor IL-10 targeted liposomes showed significant immune reaction when injected into wild-type mice. Thus, the combined use of specific anti-inflammatory proteins, high payloads of contrast agents, and liposome particles should enable current imaging techniques to better recognize and visualize AS plaques for research and prospective therapeutic strategies.

Beneficial effects of sitostanol on the attenuated immune function in asthma patients: results of an in vitro approach

Background

In vitro and animal studies have suggested that plant sterols and stanols increase cytokine production by T-helper-1 cells. This may be beneficial for patient groups characterized by a T-helper-2 dominant immune response, e.g. asthma patients. (1) to evaluate whether sitostanol induces a T-helper-1 shift in peripheral blood mononuclear cells (PBMCs) from asthma patients, and (2) to unravel the role of regulatory T-cells in this respect.

Methodology/Principal Findings

PBMCs from 10 asthma patients and 10 healthy subjects were isolated and incubated with 1.2 µM sitostanol, while stimulated with 5 µg/ml PHA. Similar amounts of cholesterol were used to determine whether effects were specific for plant stanols or for sterols in general. Changes in cytokine production were measured using antibody arrays and ELISAs. Changes in regulatory T-cell population size were measured by flow cytometry, using intracellular Foxp3 staining. Sitostanol increased production of IFNγ by 6.5% and IL-2 by 6.0% compared to cholesterol (p<0.01). No changes in IL-4 and IL-13 were found. Interestingly, this effect was only present in PBMCs from asthma patients. The number of Foxp3+ cells tended to increase and their activity, measured by IL-10 production, increased after sitostanol treatment in PBMCs from asthma patients compared to controls by 32.3% (p = 0.077) and 13.3% (p<0.05), respectively.

Conclusions/Significance

Altogether, the sitostanol-induced Thelper-1 shift in PBMCs from asthma patients and the stimulating effects of sitostanol on Treg cell numbers and activity indicate a possible novel approach for plant stanol ester enriched functional foods in the amelioration of asthmatic symptoms. Functional effects, however, require further evaluation.