Enhanced expression of B7.2 (CD86) by percutaneous sensitization with house dust mite antigen

Topical application of siRNA targeting cutaneous dendritic cells in allergic skin disease

RNA interference is a promising method for silencing specific genes and has great potential for therapeutic applications. However, the major hurdle for therapeutic application is the limited stability of double-strand RNA (dsRNA) and the absence of a reliable delivery method to target cells. Skin appears to be a favorable target for small interfering RNA (siRNA) therapy. Dendritic cells (DCs) exist in the skin and mucosae on the front lines of defense; these cells capture antigens and play a crucial role in inducing immunity and tolerance.In our recent work, we have shown a successful treatment using CD86 siRNA targeting cutaneous DCs. A costimulatory molecule, CD86, is induced on DCs in situ after antigen uptake, and CD86-expressing DCs migrate to the regional lymph nodes to present antigens to T cells. Topical application of cream-emulsified CD86 siRNA ameliorated the clinical manifestations in murine contact hypersensitivity (CH) and atopic dermatitis (AD)-like disease. Our method may be advantageous for the treatment of allergic skin diseases.

Improvement of atopic dermatitis and reduction of skin allergic responses by oral intake of konjac ceramide

Although topical application of ceramide is effective in the treatment of atopic dermatitis, its effect is transient. Thus, the effect of oral intake of ceramide on atopic dermatitis was studied. Two groups of 25 children with moderate atopic dermatitis, who were allergic to house dust mite took either milk sugar (control group) or 1.8 mg/day of konjac ceramide in milk sugar (ceramide group) once a day for 2 weeks. Before and after 2 weeks, skin symptoms were assessed using the SCORAD index, while allergic skin responses to house dust mite were assessed by skin prick test. Moreover, production of allergen-specific IgE and various cytokines by mononuclear cells was measured. After 2 weeks, SCORAD index score, allergic skin responses to house dust mite and house dust mite-specific IgE production were significantly reduced in the ceramide group, but not in the control group. Moreover, house dust mite-induced cytokine production was skewed towards the Th1 type, since production of Th1 cytokine, IFN-gamma, and IL-12, was increased, while production of Th2 cytokine, IL-4, and IL-13, was decreased. In contrast, no change of these parameters was found in control group. Collectively, oral intake of konjac ceramide improved skin symptoms and reduced allergic responses with concomitant skewing of the cytokine pattern towards the Th1 type.

Long-term anergy in orally tolerized mice is linked to decreased B7.2 expression on B cells

Durable antigen (Ag)-specific T- and B-cell anergy induced by oral tolerance is an attractive strategy for immunotherapy of allergic diseases. Here, we address the lasting effect of oral tolerance induction in naïve or primed mice to ovalbumin (OVA) on antibody production. Single feeding with OVA prior to immunization or double feeding, before and after Ag priming, in A/Sn mice, induced a long-lasting suppression of IgE, IgG1 and IgG2a responses up to 8 months after immunization. In contrast, primed-fed mice had transient IgE inhibition. Naive and double-treated mice showed marked Ag-specific unresponsiveness and scarce cytokines production. Inhibition of IL-2 and IFN-gamma secretion in naïve-fed mice were restored in the presence of anti-CD28 mAb plus Ag stimulation. The durable inhibition of Ab production in OVA-fed mice was related to the persistent decrease of B7.2 expression on B cells. Ag feeding in naive and primed status may be a prophylactic measure to avoid later Ag sensitization.

Alveolar macrophages from systemic sclerosis patients: evidence for IL-4-mediated phenotype changes

The mechanism of chronic lung inflammation leading to lung fibrosis is unknown and does not have a characteristic inflammatory macrophage phenotype. This study was undertaken to determine whether a change in macrophage phenotype could account for chronic lung inflammation. In this study, human alveolar macrophages (AM) from subjects with systemic sclerosis (SSc) were obtained from bronchoalveolar lavage (BAL) and characterized on the basis of function (response to LPS), phenotype, and relative cell-surface B7 expression. AM from the subjects' disease-involved and noninvolved lung lobes were compared with each other and to AM from normal volunteer BAL. AM from involved SSc lobes produced significantly more interleukin (IL)-1β and PGE2than AM from uninvolved lobes in response to LPS, but there was no spontaneous production of either mediator. The activator AM phenotype designated by RFD1+ surface epitope was significantly elevated in SSc BAL samples compared with normal BAL, although there were no differences comparing involved vs. noninvolved lobes within SSc subjects. The major histocompatibility complex II costimulatory molecule B7.2 was also significantly elevated in SSc AM compared with normal AM, again with no differences between involved and noninvolved lobes. In an attempt to determine environmental influences on AM phenotypes, normal AM were cultured in vitro with IFN-γ, IL-3, IL-4, IL-10, IL-12, or dexamethasone for 6 days. Of the cytokines examined, only IL-4 induced significant increases in both the activator phenotype RFD1+ and B7.2 expression. Taken together, these results indicate that IL-4 could account for proinflammatory AM phenotype changes and B7 surface-marker shifts, as seen in subjects with SSc.