Changes in Immune Responses to Antigen Applied to Tape-Stripped Skin with CpG-Oligodeoxynucleotide in NC/Nga Mice

Purpose CpG-oligodeoxynucleotide (CpG-ODN) plays a critical role in immunity via the augmentation of Th₁ and the suppression of Th₂ responses. We examined here the effect of CpG-ODN on the immune response to an antigen applied to a tape-stripped skin of NC/Nga mouse, a human atopic dermatitis (AD) model, by evaluating the production of cytokines and immunoglobulin isotypes. Methods Model antigen, ovalbumin (OVA), and CpG-ODN were applied on to the shaved skin. The penetration of OVA and CpG-ODN was evaluated using confocal laser scanning microscopy (CLSM). Secretion of cytokine from splenocytes and changes in immunoglobulin isotype levels were determined by enzyme-linked immunosorbent assay (ELISA). Results Through CLSM it was revealed that the model antigen, OVA, and CpG-ODN easily penetrated the tape-stripped skin. Coadministration of CpG-ODN and OVA to the skin elicited an antigen-specific, Th₁-predominant immune response and enhanced the production of IFN-γ. On the other hand, the production of a Th₂-type cytokine, IL-4, was drastically suppressed. In terms of antigen-specific antibody production, the level of IgG2a regulated by IFN-γ was increased by CpG-ODN, but IgE production regulated by IL-4 was suppressed. Conclusions Administration of CpG-ODN with antigen through the skin may shift the immune response from a Th₂- to Th₁-like response. These results suggested that administration of CpG-ODN via skin is a simple strategy for patients with diseases such as AD, which is characterized by Th₂-dominated inflammation.     

Therapeutic application of human leukocyte antigen-G1 improves atopic dermatitis-like skin lesions in mice

Human leukocyte antigen (HLA)-G is an immune checkpoint molecule that plays critical roles in immune response and in triggering inhibitory signaling to immune cells such as T cells, natural killer cells, and antigen-presenting cells. Thus, the application of HLA-G can be considered for treating immune response-related inflammatory disorders. We have previously reported that treatment with HLA-G1 and HLA-G2 ameliorates the joint swelling associated with collagen-induced arthritis of DBA/1 mice, an animal model for rheumatoid arthritis. In this study, we further investigated the effects of HLA-G1 on atopic dermatitis (AD), the most common inflammatory skin disorder. AD-like lesions were induced with the extract of the house dust mite Dermatophagoides farinae in NC/Nga mice. Continuous administration of HLA-G1 ameliorated the AD-like skin lesions in the mice. Furthermore, production of immunoglobulin E, interleukin (IL)-13, and IL-17A was significantly reduced in HLA-G1-treated mice, suggesting a Th2/Th17-mediated immune-inhibitory function of HLA-G1 in vivo. Our studies shed light on novel therapeutic strategies with recombinant HLA-G proteins for immune reaction-mediated chronic inflammatory disorders.     

Improvement of Atopic Dermatitis-Like Skin Lesions by <i>Platycodon grandiflorum</i> Fermented by <i>Lactobacillus plantarum</i> in NC/Nga Mice

Atopic dermatitis (AD) is characterized as a multi-factorial inflammatory skin disease that has been increasing worldwide. Previously, we demonstrated that FPG, which is Platycodon grandiflorum (PG) fermented by Lactobacillus plantarum (LP), increases the level of interferon (IFN)-gamma in mouse splenocytes in vitro. In this study, we investigated the effects of FPG in an animal model of AD, with a particular emphasis on its effects on T helper (Th)1 and Th2 immune responses. To assess the potential use of FPG for the inhibition of AD, we established a model of AD-like skin lesions in NC/Nga mice. Immunoglobulin isotypes (Igs) and Th1/Th2 cytokines in the sera and spleens of AD-like mice were examined. In addition, histological examination was also performed. AD symptoms in skin lesions improved following oral administration of FPG. IgE secretion was significantly down-regulated, and this was accompanied by decreased levels of interleukin (IL)-4 and IgG1 and increased serum levels of IL-12p40 and IgG2a in FPG-treated animals. In splenocytes, the production of the Th1 cytokines IL-12p40 and IFN-gamma was up-regulated, while the levels of the Th2 cytokines IL-4 and 5 were down-regulated by FPG treatment. These results suggest that FPG inhibits the development of AD-like skin lesions in NC/Nga mice by suppressing the Th2 cell response and increasing the Th1 cell responses. Our results indicate that FPG is safe and effective for the prevention of AD-like skin lesions.     

Resveratrol attenuates HMGB1 signaling and inflammation in house dust mite-induced atopic dermatitis in mice

Resveratrol is a polyphenol abundantly found in red grape skin and is effective against antiaging and anti-inflammation associated with immune responses. In this study, we have investigated the effect of resveratrol on skin lesion, high mobility group box (HMGB)1 and inflammation pathway in an atopic dermatitis (AD) mouse model. AD-like lesion was induced by the application of house dust mite extract to the dorsal skin of NC/Nga mouse. After AD induction, resveratrol (20 mg/kg, p.o.) was administered daily for 2 weeks. We evaluated dermatitis severity, histopathological changes, serum levels of T helper (Th) cytokines (interferon (IFN)γ, interleukin (IL)-4) and changes in protein expression by Western blotting for HMGB1, receptor for advanced glycation end products (RAGE), toll like receptor (TLR)4, nuclear factor (NF)κB, phosphatidylinositide 3-kinase (PI3K), extracellular signal-regulated kinase (ERK)1/2, cyclooxygenase (COX)2, tumor necrosis factor (TNF)α, IL-1β, IL-2Rα and other inflammatory markers in the skin of AD mice. Treatment of resveratrol inhibited the development of the AD-like skin lesions. Histological analysis showed that resveratrol inhibited hypertrophy, intracellular edema, mast cells and infiltration of inflammatory cells. Furthermore, resveratrol treatment down-regulated HMGB1, RAGE, p-NFκB, p-PI3K, p-ERK1/2, COX2, TNFα, IL-1β, IL-2Rα, IFNγ and IL-4. Considering all these findings together, the HMGB1 pathway might be a potential therapeutic target in skin inflammation, and resveratrol treatment could have beneficial effects on AD by modulating the HMGB1 protein expression.     

Augmentation of T helper type 1 immune response through intestinal immunity in murine cutaneous herpes simplex virus type 1 infection by probiotic Lactobacillus plantarum strain 06CC2

We previously found that Lactobacillus plantarum strain 06CC2 showed probiotic potential, and its oral administration effectively induced Th1 cytokine production and activated the Th1 immune response associated with intestinal immunity in mice. In this study, to evaluate its potential as a versatile oral adjuvant for treatment of viral infection, we assessed the immunomodulatory activity of 06CC2 on murine cutaneous herpes simplex virus type 1 (HSV-1) infection, in which a major immune defense system is a delayed-type hypersensitivity (DTH) reaction based on activation of the Th1 immune response, in relation to its oral efficacy for alleviation of herpetic symptoms. In the HSV-1 infection model, oral administration of 06CC2 (20 mg/mouse) twice daily for seven days starting two days before infection was significantly effective in delaying the development of skin lesions in the early phase of infection and reducing virus yields in the brain on day 4 after infection. In addition, 06CC2 significantly augmented the DTH reaction to inactivated HSV-1 antigen and elevated interferon (IFN)-γ production by HSV-1 antigen from splenocytes. On day 2, natural killer (NK) cell activity was significantly elevated, and the elevation was still observed on day 4. Furthermore, gene expressions of interleukin-12 receptor β2 and IFN-γ in Peyer's patches were augmented on day 4 by 06CC2 administration. Thus, 06CC2 was suggested to alleviate herpetic symptoms in mice in correlation with augmentation of the Th1 immune responses associated with NK cell activity through intestinal immunity. Strain 06CC2 may be a versatile oral adjuvant to activate Th1 immune response.     

DNA-based vaccination against hepatitis B virus using dissolving microneedle arrays adjuvanted by cationic liposomes and CpG ODN

DNA vaccines are simple to produce and can generate strong cellular and humoral immune response, making them attractive vaccine candidates. However, a major shortcoming of DNA vaccines is their poor immunogenicity when administered intramuscularly. Transcutaneous immunization (TCI) via microneedles is a promising alternative delivery route to enhance the vaccination efficacy. A novel dissolving microneedle array (DMA)-based TCI system loaded with cationic liposomes encapsulated with hepatitis B DNA vaccine and adjuvant CpG ODN was developed and characterized. The pGFP expression in mouse skin using DMA was imaged over time. In vivo immunity tests in mice were performed to observe the capability of DMA to induce immune response after delivery of DNA. The results showed that pGFP could be delivered into skin by DMA and expressed in skin. Further, the amount of expressed GFP was likely to peak at day 4. The immunity tests showed that the DMA-based DNA vaccination could induce effective immune response. CpG ODN significantly improved the immune response and achieved the shift of immune type from predominate Th2 type to a balance Th1/Th2 type. The cationic liposomes could further improve the immunogenicity of DNA vaccine. In conclusion, the novel DMA-based TCI system can effectively deliver hepatitis B DNA vaccine into skin, inducing effective immune response and change the immune type by adjuvant CpG ODN.     

Filaggrin in atopic dermatitis: flaky tail mice as a novel model for developing drug targets in atopic dermatitis

The barrier abnormality, a loss-of-function mutation in the gene encoding filaggrin (FLG), which is linked to the incidence of atopic dermatitis (AD), is a recently discovered but important factor in the pathogenesis of AD. To investigate this issue in greater detail, mice that have a genetic defect (FLG) in barrier function will provide a model of AD closer to the human disease. Flaky tail (Flg(ft)) mice, essentially deficient in filaggrin, recently have been introduced to investigate the role of filaggrin on AD. These mice showed eczematous skin lesion in the steady state in line with increased of total IgE and Th17 expression in the skin. There is also an altered skin barrier function as a key element of AD either outside-to-inside barrier function or vice versa in Flg(ft) mice. Moreover, like human AD, these mice showed enhanced percutaneous allergen priming or response to cutaneous stimulants. Application of mite allergen in Flg(ft) mice, even without prior barrier disruption, remarkably enhanced both the clinical manifestations and the laboratory findings that correspond to indicators of human AD. These features of Flg(ft) mice allow us to investigate further the role of filaggrin in AD, and the knowledge obtained using these mice will be quite useful to develop a new therapeutic target for AD.     

Topical delivery of plasmid DNA using biphasic lipid vesicles (Biphasix)

The development of non-invasive methods for the delivery of vaccines through the skin will greatly improve the safety and the administration of human and veterinary vaccines. In this study we examined the efficiency of topical delivery of plasmids by assessing the localization of gene expression using luciferase as a reporter gene and induction of immune responses using a plasmid encoding for the bovine herpesvirus type-1 glycoprotein D (pgD). Topical administration of plasmids in a lipid-based delivery system (biphasic lipid vesicles--Biphasix) resulted in gene expression in the lymph node, whereas with intradermal injection, antigen expression was found in the skin. Following administration of plasmid with the gene gun, antigen expression was observed in both the skin as well as in the draining lymph nodes. Transcutaneous immunization with pgD formulated in biphasic lipid vesicles elicited gD-specific antibody responses and a Th2-type cellular response. In contrast, immunization by the intradermal route resulted in the stimulation of a Th1-type response. These findings have implications for both vaccine design and tailoring of specific immune responses.     

Cell wall fraction of Mycobacterium indicus pranii shows potential Th1 adjuvant activity

Very few adjuvants inducing Th1 immune response have been developed and are under clinical investigation. Hence, there is the need to find an adjuvant that elicits strong Th1 immune response which should be safe when injected in the host along with vaccines. Mycobacterium indicus pranii (MIP), a non-pathogenic vaccine candidate, has shown strong immunomodulatory activity in leprosy/tuberculosis/cancer and in genital warts patients where its administration shifted the host immune response towards Th1 type. These findings prompted us to study the components of MIP in detail for their Th1 inducing property. Since mycobacterial cell wall is very rich in immunostimulatory components and is known to play important role in immune modulation, we investigated the activity of MIP cell wall using Ovalbumin antigen (OVA) as model antigen. ‘Whole cell wall’ (CW) and ‘aqueous soluble cell wall fractions’ (ACW) induced significant Th1 immune response while ‘cell wall skeleton’ (CWS) induced strong Th2 type of immune response. Finally, functional activity of fractions having Th1 inducing activity was evaluated in mouse model of melanoma. CW demonstrated significant anti-tumor activity similar to whole MIP. Anti-tumor activity of CW could be correlated with enhanced tumor antigen specific Th1 immune response observed in tumor draining lymph nodes.     

The potential of interleukin 12 inhibition in the treatment of psoriasis

Interleukin 12 (IL-12) is an important cytokine produced by a variety of immune effector cells that leads to a type 1 helper T cell (Th1) response. IL-12 also directs T cells to the skin via induction of cutaneous lymphocyte antigen (CLA) expression. In this article we report the current understanding of the immunobiology of IL-12, reviewing its structure, receptor, and function. We also discuss the role of IL-12 in the pathogenesis of psoriasis. Some effective conventional psoriasis treatments alter IL-12 levels. Importantly, specific antibodies directed against IL-12 may prove useful against psoriasis but may also act by targeting IL-23 in addition to IL-12.     

Polycation-decorated PLA microspheres induce robust immune responses via commonly used parenteral administration routes

Recombinant viral subunit-based vaccines have gained increasing attention due to their enhanced safety over the classic live-attenuated or inactivated vaccines. The low immunogenicity of the subunit antigen alone, however, requires the addition of an adjuvant to induce immunity. Particulate-based delivery systems have great potential for developing new vaccine adjuvants, compared to traditional aluminum-based saline adjuvants. The physicochemical properties of particulate vaccines have been extensively investigated; however, few studies have focused on how the administration route of various adjuvant–antigen combinations impacts the efficacy of the immune response. Here, for the first time, the viral Hepatitis B surface antigen (HBsAg) was combined with aluminum-based or cationic-microsphere (MP) based adjuvants to investigate the characteristics of immune responses elicited after immunization via the subcutaneous, intramuscular, or intraperitoneal routes respectively. In vitro, the MP-based vaccine significantly increased dendritic cell (DC) activation with up-regulated CD40 and CD80 expression and IL-12 production compared to alum-based vaccine. After immunization, both MP and alum-based vaccines produced increased IgG titers in mice. The administration route of these vaccines did influenced immune responses. The MP-based vaccine delivered via the intramuscular route yielded the highest levels of the IgG2a isotype. The alum-based vaccine, delivered via the same route, produced an IgG1-dominated humoral immune response. Moreover, subcutaneous and intramuscular immunizations with MP-based vaccine augmented Granzyme B, Th1-type cytokines (IL-2, IL-12, and IFN-γ), and Th2 cytokine IL-4 secretions. These results demonstrate that MP-based vaccines have the capacity to induce higher cellular and humoral immune response especially via an intramuscular administration route than an alum-based vaccine.     

Immune response to Chlamydophila abortus POMP91B protein in the context of different Pathogen Associated Molecular Patterns (PAMP); role of antigen in the orientation of immune response

In a previous study, we used bacterial flagellin to deliver antigens such as p27 of Mycobacterium tuberculosis to a host immune system and obtained a potent Th1 response compared to those obtained with Freund's adjuvant and DNA immunization. In the current study, using a POMP91B antigen of Chlamydophila abortus, a human and animal pathogen, as a model, we found that this antigen is unable to promote Th1 response. However, this antigen, unlike others, was able to induce a good Th2 response and IL-4 production after immunization by recombinant protein in Freund's adjuvant or in phosphate buffered saline. Our results suggest that immune response is not only dependent on the immunization adjuvant, but also dependent on the nature of antigen used.     

Encapsulating immunostimulatory CpG oligonucleotides in listeriolysin O-liposomes promotes a Th1-type response and CTL activity

Immunostimulatory sequences (ISS) are short DNA sequences containing unmethylated CpG dimers that have multiple effects on the host immune system, including the ability to stimulate antigen-specific cytotoxic T lymphocytes (CTLs) and drive Th1-type immune responses. Listeriolysin O (LLO)-containing pH-sensitive liposomes have been shown to efficiently deliver macromolecules to the cytosol of APCs and efficiently stimulate CTLs. We hypothesized that encapsulating ISS-oligodeoxyribonucleotides (ODNs) in this delivery system would enhance the cell-mediated immune response and skew Th1-type responses in protein antigen-based vaccination utilizing LLO-liposomes. In vitro studies indicated that coencapsulation of ISS in LLO-liposomes engendered activation of the NF-κB pathway while maintaining the efficient cytosolic delivery of antigen mediated by the coencapsulated LLO. Antigen-specific CTL responses monitored by using the model antigen ovalbumin (OVA) in mice were enhanced when mice were immunized with OVA and ISS-ODN-containing LLO-liposomes compared with those immunized with OVA-containing LLO-liposomes. The enhanced immune responses were of the Th1-type as monitored by the robust OVA-specific IgG2a induction and the OVA CD8 peptide-stimulated IFN-γ secretion. Our study suggests that including ISS-ODN in LLO-containing pH-sensitive liposomes yields a vaccine delivery system that enhances the cell-mediated immune response and skews this response toward the Th1-type.     

Use of CpG oligonucleotides in treatment of asthma and allergic disease

In the last several decades, there has been a marked increase in the prevalence of atopic disorders including asthma in “Western” societies; a relationship has been identified between lack of early-life exposure to microbes or microbial products and increased susceptibility to atopic disorders. The innate immune system is activated by early microbial exposures, many of which utilize one of the Toll-like receptors, and there has been significant interest in studying how ligation of TLRs may be therapeutically useful. CpG oligonucleotides (CpG-ODN, resembling bacterial DNA) engage TLR-9 on B-cells, dendritic cells and other cell types, resulting in a cascade that includes induction of Th1-type and T-regulatory-type immune responses. Preclinical models of asthma have demonstrated that CpG-ODN are potent inhibitors of atopic responses, suppressing Th2 cytokine and, reducing airway eosinophilia, systemic levels of IgE, and bronchial hyperreactivity-in short the critical attributes of the asthmatic phenotype. In models of chronic allergen exposure, CpG-ODN are also effective at preventing the development of airway remodeling. In established asthma, CpG-ODN can reverse manifestations of disease, both when used alone or in combination with allergen immunotherapy. Early clinical trials have had mixed results, including a significant benefit when CpG-ODN were conjugated to ragweed allergen in an allergic rhinitis immunotherapy study, but only limited efficacy seen when administered prior to allergen challenge in asthmatics. Further study of CpG-ODNs for the treatment of asthma and other atopic disorders is warranted by existing data.     

Toll-like receptors--novel targets in allergic airway disease (probiotics, friends and relatives)

Experimental and epidemiological studies enabled to hypothesize that stimulation of the immune system by selected microbial products may prevent or treat allergic diseases. According to recent advances in molecular immunology, this stimulation acts via group of conserved receptors present on antigen presenting cells, known as toll-like receptors (TLRs). These receptors play an essential role in antigen presentation and latter development of immune response into pro-allergic (Th2), cellular (Th1) or regulatory (Tr1) responses. Since toll-like receptors govern decisive points in immune regulation, an extensive research focuses on agents interfering with their immunomodulatory activities. In this report, we review information on the potential use of microbial products in allergy prevention and therapy, which are believed to target toll-like receptor network. Current toll-like receptor-based approaches, as well as potential use of lipopolysaccharide (and derivates), oligonucleotides, mycobacteria, bacterial extracts, and probiotics are discussed herein.     

Mechanism underlying the effect of combined therapy using glucosamine and low-dose cyclosporine A on the development of atopic dermatitis-like skin lesions in NC/Nga mice

Combination therapy is often used in the treatment of atopic dermatitis (AD) to improve clinical efficacy or to spare the dose of each drug. Cyclosporine A (CsA) is a calcineurin inhibitor that was developed for the treatment of AD. Glucosamine (Glu) is a potent immunosuppressant that inhibits Th2-mediated immunity. We previously reported that Glu has an ameliorative effect on the development of the pathology in NC/Nga mice. The aims of our study were to investigate the therapeutic efficacy of combination of Glu and low-dose CsA in dermatophagoides farina (Df)-induced AD-like skin lesions in NC/Nga mice and to determine the underlying therapeutic mechanisms. The Df-induced NC/Nga mice with a clinical score of 7 were used for treatment with Glu (500 mg/kg) alone, low-dose CsA (2, 5, and 10 mg/kg) or in combination. The clinical scores were reduced significantly by the combination treatment with Glu and low-dose CsA. The suppression of dermatitis by combined therapy was accompanied by decrease in the plasma level of IgE and in the splenic level of IL-4, IL-5, IL-13, TARC and eotaxin. Histological analysis of the skin also revealed that combination treatment significantly reduced the inflammatory cellular infiltrate, including mast cells and eosinophils. Particularly, immunological evaluation reveals an increase of CD4⁺CD25⁺ Treg cells in the combined treatment. The induction of TSLP, which leads to systemic Th2 response, was reduced in the skin on combination treatment. The protein expression of filaggrin and involucrin was recovered by combination treatment in the skin lesions, whereas the protein expression of keratin-10 and keratin-14 decreased in the combination treatment. Collectively, our findings suggest that combination treatment of Glu and low-dose CsA leads to the therapeutic effects in Df-induced AD-like skin lesion in NC/Nga mice through inhibition of IgE, inflammatory cellular infiltrate, and recovery of skin barrier function via a mechanism that may inhibition of Th2-mediated immune responses, in part, increment of CD4⁺CD25⁺ Treg cells. These results suggest that this combined immunosuppressive treatment may provide important implications for the design of therapeutic strategies aimed at AD treatment.     

Topical application of Pleurotus eryngii extracts inhibits 2,4-dinitrochlorobenzene-induced atopic dermatitis in NC/Nga mice by the regulation of Th1/Th2 balance

Pleurotus eryngii is a nutritional and medicinal food rich in polysaccharides that enhance the host immune system as a response to various diseases. The present study investigated the effects of P. eryngii extracts (PEE) on the progress of atopic dermatitis (AD)-like skin lesions in NC/Nga mice induced by 2,4-dinitrochlorobenzene (DNCB). We evaluated skin dermatitis severity, ear thickness, histopathological examination, and cytokines level in DNCB-applied mice treated with PEE. Continuous treatment of PEE inhibited the development of the AD-like skin lesions. PEE suppressed DNCB-induced dermatitis severity, serum level of IgE and thymus and activation-regulated chemokine (TARC), and mRNA expression of TNF-α, INF-γ, IL-4, IL-5, and IL-13 in mice. In addition, PEE reduced thickness of the dermis and dermal infiltration of inflammatory cells and mast cells in histopathological examination. These results indicate that PEE inhibits allergic contact dermatitis through the modulating of T helper (Th)1 and Th2 responses and diminishing the inflammatory cells and mast cells infiltration in the skin lesions in NC/Nga mice.     

2′-fucosyllactose inhibits imiquimod-induced psoriasis in mice by regulating Th17 cell response via the STAT3 signaling pathway

Psoriasis is a chronic immune-mediated inflammatory cutaneous disorder with Th17 cells and Th17-related cytokines playing an important role in its development. 2′-FL (2′-fucosyllactose), which makes up about 30% of all HMOs (human milk oligosaccharides) in blood type secretor positive maternal milk, plays an essential role in supporting aspects of immune development and regulation. To explore the immunomodulatory effect of 2′-FL in psoriasis, we employed the imiquimod (IMQ)-induced psoriasis-like mouse model. Our data showed that mice administered with 2′-FL exhibited attenuated skin damage and inflammation, characterized by significantly decreased erythema and thickness and reduced recruitment of pro-inflammatory cytokines, when compared to control mice. The alleviated skin inflammation in 2′-FL treated mice was associated with a reduced proportion of Th17 cells and decreased production of Th17-related cytokines. Furthermore, we have demonstrated that 2′-FL reduced the phosphorylation of STAT3 in the skin tissue from mice with IMQ stimulation, which could account for the decreasing recruitment of Th17 cells. In vitro studies showed that 2′-FL inhibited differentiation of Th17 cells, phosphorylation of STAT3, and RORγt mRNA levels in T cells under Th17 polarization. Our results indicate that 2′-FL ameliorates IMQ-induced psoriasis by inhibiting Th17 cell immune response and Th17-related cytokine secretion via modulation of the STAT3 signaling pathway.     

A novel Syk kinase-selective inhibitor blocks antigen presentation of immune complexes in dendritic cells

The initiation of antigen presentation by dendritic cells requires proper internalization of antigens through various mechanisms. Internalization of immune complexes via Fc receptors has been shown to be around 100 times more efficient than the internalization of non-complexed antigens. Spleen tyrosine kinase (Syk) plays an essential role in the signaling cascade initiated by immunoglobulin receptors. We used a selective Syk inhibitor, 7-(3,4-dimethoxyphenyl)-N-1H-indazol-6-ylimidazo[1,2-c]pyrimidin-5-amine dihydrochloride (compound-D), to evaluate the role of Syk in antigen presentation by mouse bone marrow-derived dendritic cells. In line with our expectation, compound-D concentration-dependently inhibited the internalization of immune complexes but not that of antigen itself. Furthermore, when dendritic cells were pretreated with compound-D, the ability of dendritic cells to present immune complex antigens to Th2 cells was attenuated, parallel by a reduced release of interleukin-4 production in Th2 cells. Therefore, Syk kinase activity is a critical component in the process of Fcgamma receptor-mediated internalization of immune complex antigens in dendritic cells, and Syk kinase inhibitors may be beneficial in selectively suppressing antibody-mediated antigen presentation in allergic diseases.     

Biodegradable nanoparticle delivery of a Th2-biased peptide for induction of Th1 immune responses

The type of immune response developed against the hepatitis B virus (HBV) is crucial in determining the outcome of the disease. The protective effects of vaccine-induced antibody responses against subsequent exposure to HBV are well-established. After the establishment of chronic HBV infection, cell-mediated immune response is curative while humoral response is detrimental. A therapeutic vaccine that could switch the type of response could lead to disease resolution. Hepatitis B core antigen (HBcAg)(129-140) has been identified as a Th2-biased peptide in H-2(b) mice when it is administered along with complete Freund's adjuvant (CFA). We formulated HBcAg(129-140) along with monophosphoryl lipid A in poly(D,L-lactic-co-glycolic acid) (PLGA) nanoparticles. Naive mice immunized with the nanoparticle formulation developed a strong Th1-type response while mice immunized with the control formulation of CFA and peptide did not. We then primed mice with CFA and peptide to establish a Th2-type immune response before administering the nanoparticle formulation. Mice receiving the nanoparticle formulation being primed with CFA still developed a strong Th1-type response, while mice that received incomplete Freund's adjuvant and peptide instead of nanoparticles did not. The ability of PLGA nanoparticles to alter the type of immune response elicited by a peptide, even in the context of an ongoing immune response, makes PLGA nanoparticles a strong candidate for the formulation of therapeutic vaccines.