α-Galactosylceramide (α-GalCer) is a ligand of invariant Vα14+ NKT cells and is presented by CD1d molecule on APC. NKT cells produce a large amount of Th1 and Th2 cytokines in response to α-GalCer-presented APC. In this study, we assessed whether α-GalCer could act as an effective nasal vaccine adjuvant for mucosal vaccine that would be capable of inducing systemic as well as mucosal immune responses. When α-GalCer was administered with OVA via the intranasal route to C57BL/6 and BALB/c mice, significant OVA-specific mucosal secretory IgA, systemic IgG, and CTL responses were induced with mixed Th1 and Th2 cytokine profiles seen in both strains of mice. Interestingly, as BALB/c mice were intranasally immunized with PR8 hemagglutinin Ag isolated from influenza virus A/PR/8/34 together with α-GalCer, significant protection was afforded against influenza viral infection. When α-GalCer was coimmunized with a replication-deficient live adenovirus to BALB/c mice, it significantly induced both humoral and cellular immune responses. In addition, intranasal administration of OVA with α-GalCer showed complete protection against EG7 tumor challenge in C57BL/6. The adjuvant effects induced by intranasal coadministration with α-GalCer were blocked in CD1d−/− mice, indicating that the immune responses were exclusively mediated by CD1d molecule on APC. Most interestingly, intranasally coadministered α-GalCer activated naive T cells and triggered them to differentiate into functional effector T cells when CFSE-labeled OT-1 cells were adoptively transferred into syngeneic mice. Overall, our results are the first to show that α-GalCer can act as a nasal vaccine adjuvant inducing protective immune responses against viral infections and tumors.

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Genetic and epigenetic programming of T helper (Th) cell subsets during their polarization from naive Th cells establishes long-lived memory Th cells that stably maintain their lineage signatures. However, whether memory Th cells can be redifferentiated into another Th lineage is unclear. In this study, we show that Ag-specific memory Th cells were redifferentiated into Foxp3 + T cells by TGF-β when stimulated in the presence of all-trans retinoic acid and rapamycin. The "converted" Foxp3 + T cells that were derived from Th2 memory cells downregulated GATA-3 and IRF4 and produced little IL-4, IL-5, and IL-13. Instead, the converted Foxp3 + T cells suppressed the proliferation and cytokine production of Th2 memory cells. More importantly, the converted Foxp3 + T cells efficiently accumulated in the airways and significantly suppressed Th2 memory cell-mediated airway hyperreactivity, eosinophilia, and allergen-specific IgE production. Our findings reveal the plasticity of Th2 memory cells and provide a strategy for adoptive immunotherapy for the treatment of allergic diseases.all-trans retinoic acid | immune tolerance | immunotherapy | plasticity | rapamycin

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PurposeThe prevalence of allergic diseases is known to be associated with both demographic and environmental factors. Herein, we aimed to determine significant factors associated with the prevalence of allergic diseases and with total immunoglobulin E (tIgE) and specific immunoglobulin E (sIgE) levels in Korea.MethodsWe analyzed unweighted data collected by the 2010 Korea National Health and Nutrition Examination Survey for 2,342 subjects who underwent serum tests for tIgE and sIgE to Dermatophagoides farinae, dog, and Blattella germanica, representing a sample of 16,003,645 citizens, by considering the sample weight and stratification.ResultsThe overall prevalence of self-reported allergic diseases was 37.6%. The prevalence rates of allergic rhinitis and atopic dermatitis decreased with age, whereas the asthma prevalence was not affected by the age of the subjects. When analyzed according to the type of allergic diseases, the prevalence of self-reported allergic disease was significantly associated with various factors (e.g. age, occupation, living in urban areas, and depression). The tIgE level decreased with age, but later increased. Elevation of tIgE was significantly associated with male sex, type of occupation, obesity, and smoking status. However, the risk factors for the increased sIgE levels to each allergen were quite different. Sensitization to D. farinae was more likely in young subjects, whereas the prevalence of sensitization to B. germanica was significantly higher in subjects with male sex, residing in a house (houses), and with glucose intolerance. Finally, young age and the smoking status were significantly associated with sensitization to dog.ConclusionsVarious demographic and environmental factors were significantly associated with the prevalence of self-reported allergic diseases and the levels of tIgE and sIgE to D. farinae, B. germanica, and dog in Korea.