krn-7000 and Hypersensitivity

Topics: Allergens; Animals; Antigen Presentation; B-Lymphocytes; Cell Differentiation; Drug Design; Galactosylceramides; Humans; Hypersensitivity; Immunoglobulin E; Liposomes; T-Lymphocytes; T-Lymphocytes, Helper-Inducer; T-Lymphocytes, Regulatory; Vaccines

Valpha14 natural killer T (NKT) cells produce large amounts of both IL-4 and IFN-gamma upon stimulation with a ligand, alpha-galactosylceramide (alpha-GalCer), and play a crucial role in various immune responses, including allergic reactions. Interestingly, Valpha14 NKT cells are not essential for the induction of specific IgE response but they instead tend to induce suppression of specific IgE upon alpha-GalCer activation in vivo. The suppression in the IgE production is not detected either in Valpha14 NKT cell-deficient mice or in IFN-gamma-deficient mice. Therefore, activated Valpha14 NKT cells are able to exert a potent suppressive activity on Th2 cell differentiation and subsequent IgE production by producing a large amount of IFN-gamma. In an OVA-induced asthma model, alpha-GalCer administration inhibited airway inflammation and airway hyperreactivity by IFN-gamma from activated Valpha14 NKT cells, thus suggesting the negative regulation of Th2-responses by the activated Valpha14 NKT cells.

Topics: Animals; Antigens, Differentiation, B-Lymphocyte; Cell Differentiation; Galactosylceramides; Histocompatibility Antigens Class II; Humans; Hypersensitivity; Killer Cells, Natural; Lymphocyte Activation; Receptors, Immunologic; T-Lymphocyte Subsets; Th1 Cells; Th2 Cells

Natural killer T (NKT) cells constitute a T cell subpopulation that shares several characteristics with NK cells. NKT cells are characterized by a narrow T cell antigen receptor (TCR) repertoire, recognize glycolipid antigen in the context of the monomorphic CD1d antigen-presenting molecule, and have the unique capacity to rapidly produce large amounts of both T helper (Th) 1 and Th2 cytokines. Important roles of NKT cells have now been demonstrated in the regulation of autoimmune, allergic, antimicrobial, and antitumor immune responses. Here, we review the immunoregulatory role of NKT cells in disease and discuss NKT cell based immunotherapeutic strategies.

Topics: Adjuvants, Immunologic; Animals; Antigens, CD1; Antigens, CD1d; Autoimmune Diseases; Communicable Diseases; Galactosylceramides; Graft Survival; Humans; Hypersensitivity; Immunotherapy; Killer Cells, Natural; Mice; Neoplasms; T-Lymphocytes

Allergic conditions affect more than a quarter of the population in developed countries, but currently available treatments focus more on symptom relief than treating the underlying atopic condition. α-Galactosylceramide (α-GalCer) is a potent immunomodulating compound that has been shown to have a regulatory effect when delivered systemically in nanoparticles. Parenteral delivery is not preferred for chronic conditions, such as allergy, and therefore, the aim of this study was to determine whether a regulatory response could be induced through oral administration in a model of atopy through incorporation of α-GalCer into stable particulate formulations (cationic liposomes, polymerized liposomes and poly(lactic-co-glycolic acid) nanoparticles (PLGA NPs)). The formulations showed only minor changes in particle size, polydispersity index and retention of the model antigen ovalbumin (OVA) during incubation in simulated gastrointestinal (GI) conditions. Oral delivery of α-GalCer in cationic liposomes could induce immunostimulating effects systemically, as seen through increases in serum IgG antibody levels, whereas delivery of α-GalCer in polymerized liposomes and PLGA NPs induced local cytokine changes in the mesenteric lymph nodes (MLNs). The generated responses did not exhibit tolerogenic traits which could be useful for immunoregulation, but the responses generated varied between formulations and suggests that further characterization and optimization could lead to the desired immune response.

Topics: Administration, Oral; Animals; Drug Carriers; Drug Compounding; Galactosylceramides; Humans; Hypersensitivity; Mice, Inbred C57BL; Nanoparticles; Vaccines

Chronic inflammatory disorder of the airways causes asthma. Regulatory T cells (Treg cells) and Natural killer T cells (NKT cells) both play critical roles in the pathogenesis of asthma. Activation of Treg cells requires Foxp3, whereas whether Foxp3 may regulate the ratio of Treg and NKT cells to affect asthma is uncertain. In an ovalbumin (OVA)-induced mouse model of asthma, we either increased Treg cells by lentivirus-mediated forced expression of exogenous Foxp3, or increased NKT cells by stimulation with its activator α-GalCer. We found that the CD4+CD25+ Treg cells increased by forced Foxp3 expression, and decreased by α-GalCer, while the CD3+CD161+ NKT cells decreased by forced Foxp3 expression, and increased by α-GalCer. Moreover, forced Foxp3 expression, but not α-GalCer, significantly alleviated the hallmarks of asthma. Furthermore, forced Foxp3 increased levels of IL_10 and TGFβ1, and α-GalCer increased levels of IL_4 and INFγ in the OVA-treated lung. Taken together, our study suggests that Foxp3 may activate Treg cells and suppress NKT cells in asthma. Treg and NKT cells may antagonize the effects of each other in asthma.

Topics: Animals; Asthma; Cytokines; Disease Models, Animal; Forkhead Transcription Factors; Galactosylceramides; HEK293 Cells; Humans; Hypersensitivity; Lentivirus; Male; Mice, Inbred C57BL; Natural Killer T-Cells; Ovalbumin; T-Lymphocytes, Regulatory

Invariant natural killer T (iNKT) cells play important immunoregulatory functions in allergen-induced airway hyperresponsiveness and inflammation. To clarify the role of iNKT cells in allergic rhinitis (AR), we generated bone marrow-derived dendritic cells (BMDCs), which were pulsed by ovalbumin (OVA) and α-galactosylceramide (OVA/α-GalCer-BMDCs) and administered into the oral submucosa of OVA-sensitized mice before nasal challenge. Nasal symptoms, level of OVA-specific immunoglobulin (IgE), and T helper type 2 (Th2) cytokine production in cervical lymph nodes (CLNs) were significantly ameliorated in wild-type (WT) mice treated with OVA/α-GalCer-BMDCs, but not in WT mice treated with OVA-BMDCs. These anti-allergic effects were not observed in Jα18(-/-) recipients that lack iNKT cells, even after similar treatment with OVA/α-GalCer-BMDCs in an adoptive transfer study with CD4(+) T cells and B cells from OVA-sensitized WT mice. In WT recipients of OVA/α-GalCer-BMDCs, the number of interleukin (IL)-21-producing iNKT cells increased significantly and the Th1/Th2 balance shifted towards the Th1 dominant state. Treatment with anti-IL-21 and anti-interferon (IFN)-γ antibodies abrogated these anti-allergic effects in mice treated with α-GalCer/OVA-BMDCs. These results suggest that activation of iNKT cells in regional lymph nodes induces anti-allergic effects through production of IL-21 or IFN-γ, and that these effects are enhanced by simultaneous stimulation with antigen. Thus, iNKT cells might be a useful target in development of new treatment strategies for AR.

Topics: Animals; B-Lymphocytes; CD4-Positive T-Lymphocytes; Dendritic Cells; Epitopes; Female; Galactosylceramides; Hypersensitivity; Immunoglobulin E; Immunotherapy, Adoptive; Interferon-gamma; Interleukins; Lymph Nodes; Lymphocyte Activation; Mice; Mice, Inbred BALB C; Natural Killer T-Cells; Ovalbumin; Rhinitis; Th1 Cells; Th2 Cells

Epitope-based peptide vaccines encompass minimal immunogenic regions of protein antigens to allow stimulation of precisely targeted adaptive immune responses. However, because efficacy is largely determined by the functional status of antigen-presenting cells (APCs) that acquire and present peptides to cells of the adaptive immune system, adjuvant compounds are needed to enhance immunogenicity. We present here a vaccine consisting of an allergen-derived peptide conjugated to a prodrug of the natural killer-like T (NKT) cell agonist α-galactosylceramide, which is highly effective in reducing inflammation in a mouse model of allergic airway inflammation. Unlike other peptide-adjuvant conjugates that directly activate APCs through pattern recognition pathways, this vaccine encourages third-party interactions with NKT cells to enhance APC function. Therapeutic efficacy was correlated with marked increases in the number and functional activity of allergen-specific cytotoxic T lymphocytes (CTLs), leading to suppression of immune infiltration into the lungs after allergen challenge in sensitized hosts.

Topics: Adjuvants, Immunologic; Allergens; Animals; Anti-Inflammatory Agents; Antigen-Presenting Cells; Disease Models, Animal; Female; Galactosylceramides; Hypersensitivity; Immunoglobulin E; Inflammation; Male; Mice; Mice, Inbred C57BL; Molecular Conformation; Natural Killer T-Cells; Peptides; Prodrugs; T-Lymphocytes, Cytotoxic; Vaccines

One experimental approach for the treatment of allergic reactions is the stimulation of immunoregulatory NKT cells with the synthetic glycolipid αgalactosylceramide. For a first evaluation of the immunomodulatory potential of αGalCerMPEG a human in vitro allergy model was exploited. Acting as an adjuvant, the glycolipid induced an enhanced Th1-biased allergen-specific immune response of autologous lymphocytes. In a mouse model of allergic airway inflammation, αGalCerMPEG-activated NKT cells promoted a cytokine environment in the spleen, leading to priming of Th1 cells. The shift towards a Th1-dominated allergen-specific immune response thus might mediate the abrogation of allergic airway inflammation and thereby might provide a valid option for therapeutic intervention.

Topics: Adolescent; Adult; Animals; Cells, Cultured; Cytokines; Female; Galactosylceramides; Humans; Hypersensitivity; Immunologic Factors; Inflammation; Male; Mice; Mice, Inbred BALB C; Middle Aged; Natural Killer T-Cells; Spleen; Th1 Cells; Young Adult

Using an allergen-induced airway inflammation model, we show that an injection of alpha-galactosylceramide (alpha-GalCer), a ligand for invariant NK T (iNKT) cells, induced IL-27 and that this process is essential for the attenuation of the Th2 response. After the systemic administration of alpha-GalCer into the mice primed with OVA in alum, Th2 cytokine production of OVA-primed CD4(+) T cells in their lymph nodes, IgG1 and IgE Ab formation, and infiltration of eosinophils in bronchoalveolar lavage after the OVA challenge were suppressed. Systemic administration of rIFN-gamma into OVA-primed mice could not reproduce these effects of alpha-GalCer. IL-27p28 was detected both in the culture supernatant of alpha-GalCer-stimulated spleen cells and in the serum of the alpha-GalCer-treated mice, but not in the iNKT cell-deficient mice. Splenic iNKT cells produced IL-27p28 in the culture supernatant upon stimulation with PMA plus ionomycin, although the transcript of IL-27p28 in the iNKT cells was constitutively expressed regardless of the stimulation. By contrast, the transcript of IL-27EBI3 was induced in the iNKT cells upon stimulation with PMA plus ionomycin in vitro and with alpha-GalCer treatment in vivo, suggesting that IL-27 (p28/EBI3) could be produced by iNKT cells in an activation-dependent manner. Although repeated injections of rIL-27 did not substitute for the effects of a single injection of alpha-GalCer, administration of rIL-27 along with rIFN-gamma reproduced in vivo effects of the alpha-GalCer injection. These data indicate that production of both IL-27 and IFN-gamma by the alpha-GalCer treatment is responsible for suppression of the Th2 response and allergic inflammation.

Topics: Animals; Asthma; Cells, Cultured; Disease Models, Animal; Female; Galactosylceramides; Hypersensitivity; Immunosuppression Therapy; Inflammation Mediators; Injections, Intraperitoneal; Interferon-gamma; Interleukins; Ligands; Mice; Mice, Inbred BALB C; Mice, Knockout; Natural Killer T-Cells; Th2 Cells

We report here that the delivery of both alpha-galactosylceramide (alphaGalCer), a representative ligand for invariant natural killer T (iNKT) cells, and an antigenic polypeptide to marginal zone B cells induces the differentiation of regulatory cells in vivo, and suppresses the secondary antibody responses in mice. Splenic CD21+ CD23- B cells of mice treated with alphaGalCer-liposomes produce IL-10 when co-cultured with iNKT cells, whereas the cells treated with aqueous alphaGalCer fail to do so. Adoptive transfer of the B cells into syngenic mice leads to the expansion of splenic CD11c(low) CD45RB(high) cells, which convert naive CD4+ T cells from RAG2-deficient DO11.10 mice to CD4+ CD25(high) Foxp3+ T cells in the presence of OVA323-339 peptide. Administration of alphaGalCer-OVA-liposomes into OVA-primed mice causes the development of CD4+ CD25(high) Foxp3+ T cells that produce both IL-10 and IFN-gamma, and induced the antigen-specific suppression of the secondary antibody responses when boosted with OVA alone. These results indicate that antigen-containing alphaGalCer-liposomes can facilitate the development of tolerogenic antigen-presenting cells and inducible regulatory T cells that are involved in the suppression of immune responses to antigens.

Topics: Animals; Anti-Allergic Agents; CpG Islands; Crosses, Genetic; Dendritic Cells; Female; Galactosylceramides; Hypersensitivity; Immunotherapy; Liposomes; Male; Mice; Mice, Inbred BALB C; Mice, Inbred C57BL; Mice, Inbred DBA; Spleen; T-Lymphocytes; T-Lymphocytes, Regulatory

alpha-Galactosylceramide (alpha-GalCer) is a specific ligand of natural killer T cells (NKT cells) that regulates the immune responses such as tumor rejection and autoimmunity by producing interferon (IFN)-gamma and interleukin (IL)-4. However, it has not been determined whether alpha-GalCer-activated NKT cells modulate allergic inflammation. Because alpha-GalCer induces a large amount of IFN-gamma production by NKT cells, we hypothesized that an in vivo administration of alpha-GalCer could inhibit allergic airway inflammation in mice. Strikingly, a single intraperitoneal injection of alpha-GalCer almost completely abrogated an infiltrate with eosinophils in the lung tissue as well as in the bronchoalveolar lavage. This inhibition of allergic inflammation was associated with a significant decrease in the levels of IL-4, IL-5, and IL-13 in bronchoalveolar lavage fluid and in the number of goblet cells. In addition, this ligand significantly inhibited airway hyperresponsiveness to inhaled methacholine and raised the serum levels of ovalbumin-specific IgG2a with a decrease in those of ovalbumin-specific IgE. In IFN-gamma knockout mice, however, alpha-GalCer failed to exert such inhibitory effects in this asthma model. These results indicate that alpha-GalCer prevents allergic airway inflammation possibly through IFN-gamma production by ligand-activated NKT cells, suggesting the potential therapeutic application of alpha-GalCer in asthma.

Topics: Animals; Antigens; Asthma; Bronchoalveolar Lavage Fluid; Cytotoxicity, Immunologic; Disease Models, Animal; Enzyme-Linked Immunosorbent Assay; Galactosylceramides; Goblet Cells; Hyperplasia; Hypersensitivity; Immunoglobulin E; Immunoglobulin G; Inflammation; Interferon-gamma; Killer Cells, Natural; Ligands; Lung; Mice; Mice, Inbred BALB C; Mice, Knockout; Ovalbumin; T-Lymphocytes; Th2 Cells; Time Factors

Allergic asthma is a multifaceted syndrome consisting of eosinophil-rich airway inflammation, bronchospasm, and airway hyper-responsiveness (AHR). Using a mouse model of allergic asthma, we previously reported that invariant NKT (iNKT) cells increase the severity of this disease. Herein, we demonstrate that a single i.v. injection of alpha-galactosylceramide (alpha-GalCer), 1 h before the first airway allergen challenge of OVA-sensitized mice, abrogates elicitation of AHR, airway eosinophilia, IL-4 and IL-5 production in bronchoalveolar lavage fluid, and specific anti-OVA IgE antibodies. Further, alpha-GalCer administered intranasally also strongly inhibited the major symptoms of asthma in sensitized and challenged mice. Alpha-GalCer treatment induces iNKT cell accumulation in the lungs, and shifts their cytokine profile from pro-asthmatic IL-4 to a protective IFN-gamma production. The role of IFN-gamma from iNKT cells in protection was shown by adoptive transfer of sorted iNKT cells from OVA-sensitized and alpha-GalCer-treated mice which protected immunized recipients from manifesting asthma by an IFN-gamma-dependent pathway. Our findings demonstrate for the first time that alpha-GalCer administered locally inhibits asthma symptoms, even in predisposed asthmatic mice, through an iNKT cell- and IFN-gamma-dependent pathway.

Topics: Administration, Intranasal; Adoptive Transfer; Animals; Asthma; Bronchial Hyperreactivity; Bronchoalveolar Lavage Fluid; Cytokines; Disease Models, Animal; Flow Cytometry; Galactosylceramides; Hypersensitivity; Injections, Intravenous; Interferon-alpha; Killer Cells, Natural; Male; Mice; Ovalbumin