1,25-Dihydroxyvitamin D3 Inhibits the Differentiation and Migration of TH17 Cells to Protect against Experimental Autoimmune Encephalomyelitis

BACKGROUND: Vitamin D(3), the most physiologically relevant form of vitamin D, is an essential organic compound that has been shown to have a crucial effect on the immune responses. Vitamin D(3) ameliorates the onset of the experimental autoimmune encephalomyelitis (EAE); however, the direct effect of vitamin D(3) on T cells is largely unknown. METHODOLOGY/PRINCIPAL FINDINGS: In an in vitro system using cells from mice, the active form of vitamin D(3) (1,25-dihydroxyvitamin D(3)) suppresses both interleukin (IL)-17-producing T cells (T(H)17) and regulatory T cells (Treg) differentiation via a vitamin D receptor signal. The ability of 1,25-dihydroxyvitamin D(3) (1,25(OH)(2)D(3)) to reduce the amount of IL-2 regulates the generation of Treg cells, but not T(H)17 cells. Under T(H)17-polarizing conditions, 1,25(OH)(2)D(3) helps to increase the numbers of IL-10-producing T cells, but 1,25(OH)(2)D(3)'s negative regulation of T(H)17 development is still defined in the IL-10(-/-) T cells. Although the STAT1 signal reciprocally affects the secretion of IL-10 and IL-17, 1,25(OH)(2)D(3) inhibits IL-17 production in STAT1(-/-) T cells. Most interestingly, 1,25(OH)(2)D(3) negatively regulates CCR6 expression which might be essential for T(H)17 cells to enter the central nervous system and initiate EAE. CONCLUSIONS/SIGNIFICANCE: Our present results in an experimental murine model suggest that 1,25(OH)(2)D(3) can directly regulate T cell differentiation and could be applied in preventive and therapeutic strategies for T(H)17-mediated autoimmune diseases

Live Vaccinia Virus-Coated Microneedle Array Patches for Smallpox Vaccination and Stockpiling

Although smallpox has been eradicated globally, the potential use of the smallpox virus in bioterrorism indicates the importance of stockpiling smallpox vaccines. Considering the advantages of microneedle-based vaccination over conventional needle injections, in this study, we examined the feasibility of microneedle-based smallpox vaccination as an alternative approach for stockpiling smallpox vaccines. We prepared polylactic acid (PLA) microneedle array patches by micromolding and loaded a second-generation smallpox vaccine on the microneedle tips via dip coating. We evaluated the effect of excipients and drying conditions on vaccine stability in vitro and examined immune responses in female BALB/c mice by measuring neutralizing antibodies and interferon (IFN)-γ-secreting cells. Approximately 40% of the virus titer was reduced during the vaccine-coating process, with or without excipients. At −20 °C, the smallpox vaccine coated on the microneedles was stable up to 6 months. Compared to natural evaporation, vacuum drying was more efficient in improving the smallpox vaccine stability. Microneedle-based vaccination of the mice elicited neutralizing antibodies beginning 3 weeks after immunization; the levels were maintained for 12 weeks. It significantly increased IFN-γ-secreting cells 12 weeks after priming, indicating the induction of cellular immune responses. The smallpox-vaccine-coated microneedles could serve as an alternative delivery system for vaccination and stockpiling

Lack of retinoic acid leads to increased langerin-expressing dendritic cells in gut-associated lymphoid tissues.

International audienceThese results suggest that generation of langerin(+) DCs in the GALT is tightly regulated by RA and that the microenvironment of tissues determines the phenotype of DCs

Effects of Various LED Light Colors on Growth and Immune Response in Broilers

We evaluated the effects of different light-emitting diode (LED) colors between blue and green on growth performance and the immune response in broilers. A total of 1,200 1-day-old Ross broilers were divided randomly into six groups and exposed to pure blue (PB), bright blue (BB), sky blue (SB), greenish blue (GB), pure green (PG), or white (W) using LEDs for 6 weeks. Consequently, body weights were higher in chickens reared under PB and GB on day (d) 7 and SB on d 21 than the other groups. Chickens in the PB group on d 42 were the heaviest among the groups, followed by the BB group and were significantly heavier than the W group. Splenocyte proliferation was significantly enhanced in chickens reared under PB followed by BB on d 42 and proliferation of peripheral blood mononuclear cells was significantly enhanced in chickens reared under BB on d 42. In addition, chickens in the BB group showed significantly elevated nitric oxide production on d 42, indicating activation of macrophages. These results suggest that immune function and growth of broilers can be improved at the later stage by rearing under shorter wavelength LEDs such as PB and BB

The inhibitory mechanism of 1,25(OH)₂D₃ is independent of the STAT1 signal.

<p>Naïve CD4⁺ T cells from STAT1^+/+ and STAT1^−/− mice (B6 background) were cultured with anti-CD3 Abs (1 µg/ml) in the presence of CD3-depleted splenocytes for 4 days under various cytokine treatment conditions (IL-27, 10 ng/ml; TGF-β, 1 ng/ml; IL-6, 20 ng/ml; anti-IFN-γ, 10 mg/ml; or anti-IL-4, 10 mg/ml) with 1,25(OH)₂D₃ (100 nM) and then stained intracellularly for IL-17A and IL-10. Data are representative of three independent experiments with at least three mice per group. **p<0.01 compared with cytokine-alone group.</p

1,25(OH)₂D₃ negatively regulates Treg and T_H17 induction in OVA-specific CD4⁺ T cells.

<p>(<b>A</b>) Naïve CD4⁺ T cells from Rag2^−/− DO11.10 mice (BALB/c background) were cultured with 0.25 µM OVA_323–339 peptide in the presence of CD3⁺ T cell-depleted splenocytes for 4 days under polarizing conditions (Treg, T_H17, or T_H1) together with retinoic acid (RA, 100 nM) or 1,25(OH)₂D₃ (VitD, 100 nM) as described for <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0012925#pone-0012925-g002" target="_blank">Figure 2</a>. Then cells were stained intracellularly for Foxp3, IL-17, or IFN-γ, respectively. The plots shown are gated on CD4⁺KJ1-26⁺ cells with quadrants drawn based on isotype controls. The numbers in the quadrants indicate cell percentages (left). Means ± SD of triplicate samples are plotted (right). Data are representative of five independent experiments with at least three mice per group. **p<0.01 compared with each cytokine-alone group. (<b>B</b>) Expression of Foxp3 and IL-17 genes was analyzed by quantitative PCR. Data are representative of five independent experiments with at least three mice per group.</p

Exogenous IL-2 recovers the decreased Treg but not T_H17 generation by 1,25(OH)₂D₃.

<p>Naïve CD4⁺ T cells from Rag2^−/− DO11.10 mice (BALB/c background) were cultured with 0.25 µM OVA_323–339 peptide in the presence of CD3⁺ T cell-depleted splenocytes for 4 days. (<b>A</b>) Under Treg-polarizing conditions with 1,25(OH)₂D₃ (0.1, 1, 10, and 100 nM), culture supernatants were analyzed for IL-2 production by ELISA. (<b>B</b>) Under Treg-polarizing conditions, IL-2 cytokine was added in 1,25(OH)₂D₃-treated groups in a dose-dependent manner (IL-2: 0.1, 1, 10, and 20 ng/ml); 4 days later the CD4⁺ T cells were stained intracellularly for Foxp3. (<b>C</b>) Under T_H17-polarizing conditions, 1,25(OH)₂D₃ (100 nM) and IL-2 (0.1, 1, 10, and 20 ng/ml) were added. The average frequency of IL-17A⁺ T cells in gated CD4⁺KJ1-26⁺ cells is shown. Means ± SD of triplicate samples are plotted. Data are representative of three independent experiments with at least three mice per group. *p<0.05, ***p<0.001 compared with cytokine-alone group.</p

1,25(OH)₂D₃ inhibits the onset of EAE and modulates the composition of T_H cells.

<p>(<b>A</b>) Disease scores are shown for EAE in B6 mice at various time points after subcutaneous immunization with MOG_35–55 peptide in CFA and pertussis toxin. Results shown are mean ± SD. **p<0.01, ***p<0.001, compared with EAE-PBS group. (<b>B</b>) At 20 days after challenge, total mononuclear cells obtained from the brains of MOG_35–55-immunized wild-type mice and vitamin D_3-treated mice and stained with anti-CD4 and anti-CD3 Abs. Data are representative of three independent experiments with at least five mice per group. ***p<0.001, compared with EAE-PBS group. (<b>C</b>) Mononuclear cells from brains or splenocytes were restimulated <i>in vitro</i> with PMA/ionomycin for 5 hr, then stained intracellularly for Foxp3, IL-17A, IL-10, and IFN-γ. Data are representative of three independent experiments with at least five mice per group. *p<0.05, compared with splenocytes of EAE-PBS group.</p