Oral tolerance modulates the skin transcriptome in mice with induced atopic dermatitis.

Defective gut immune reactions have been implicated in the development of atopic dermatitis (AD), whereas oral tolerance (OT), that is, the immune unresponsiveness induced by oral antigen administration, protects mice against AD. To investigate this protective role of OT, the transcriptomic profiles of skin were obtained by RNA sequencing from mice that were epicutaneously sensitized, orally tolerized prior to epicutaneous sensitization, or neither (control). Oral tolerance inhibited the upregulation of keratin- and allergic inflammation-associated genes that occurred in the epicutaneously sensitized group. Compared to the controls, mice that were orally tolerized and epicutaneously sensitized showed an upregulation of genes that regulate inflammation or keratinocyte differentiation. Knocking down two of those genes, SCGB1A1 and TSC22D3, upregulated Th2 inflammatory mediators and downregulated a cornified cell envelope-related gene. Based on our findings, OT may protect skin against allergic inflammation by promoting the expression of genes that regulate Th2 inflammatory responses and skin barrier function.

Oral tolerance inhibits atopic dermatitis-like type 2 inflammation in mice by modulating immune microenvironments.

BACKGROUND: Oral tolerance is immune unresponsiveness induced by oral administration of innocuous antigens. Oral administration of allergens has been shown to be effective for suppressing IgE production in allergic responses. However, whether oral tolerance has a role in protection from allergic skin inflammation has not been fully investigated. Here, we evaluated the potential protective role of oral tolerance in a murine model of atopic dermatitis (AD) and investigated the underlying immunologic mechanisms. METHODS: Mice were fed with ovalbumin (OVA) in drinking water then epicutaneously sensitized by repeated application of OVA to tape-stripped skin. Skin biopsies were analyzed for immunohistopathologic features. Levels of antibodies in sera and intestinal washes were measured by ELISA. Flow cytometry and real-time PCR analysis of the skin and mesenteric lymph nodes (MLN) were performed to investigate the immunologic effects of oral tolerance in epicutaneous (EC) sensitization-induced allergic responses. RESULTS: Induction of oral tolerance effectively inhibited inflammatory responses provoked by EC sensitization. Tolerogenic immune mediators were significantly increased in the skin and MLN of EC-sensitized mice following induction of oral tolerance. A marked increase in Il5 and Il13 expression and infiltration of eosinophils and type 2 innate lymphoid cells (ILC2) in the skin of EC-sensitized mice were significantly inhibited by oral tolerance. CONCLUSIONS: Oral tolerance plays a protective role in the development of AD in a murine model by modulating immune microenvironments to be more favorable for immune regulation. This modulation involves inhibition of ILC2 infiltration in skin lesions.

Production of human papillomavirus type 33 L1 major capsid protein and virus-like particles from Bacillus subtilis to develop a prophylactic vaccine against cervical cancer.

We developed a bacterial expression system to produce human papillomavirus (HPV) type 33 L1 major capsid protein and virus-like particles from a recombinant Bacillus subtilis strain. For the first time, we have isolated self-assembled virus-like particles (VLPs) of HPV type 33 from B. subtilis, a strain generally recognized as safe (GRAS). The gene encoding the major capsid protein L1 of HPV type 33 was amplified from viral DNA isolated from a Korean patient and expressed in B. subtilis; a xylose-induction system was used to control gene activity. HPV33 L1 protein was partially purified by 40% (w/v) sucrose cushion centrifugation and strong cation exchange column chromatography. Eluted samples exhibited immunosignaling in fractions of 0.5-1.0 M NaCl. The HPV33 L1 protein was shown to be approximately 56 kDa in size by SDS-PAGE and Western blotting; recovery and purity were quantified by indirect immuno-ELISA assay. The final yield and purity were approximately 20.4% and 10.3%, respectively. Transmission electron microscopic analysis of fractions immunoactive by ELISA revealed that the L1 protein formed self-assembled VLPs with a diameter of approximately 20-40 nm. Humoral and cellular immune responses provoked by the B. subtilis/HPV33 L1 strain were approximately 100- and 3-fold higher than those of the empty B. subtilis strain as a negative control, respectively. Development of a VLP production and delivery system using B. subtilis will be helpful, in that the vaccine may be convenient production as an antigen delivery system. VLPs thus produced will be safer for human use than those purified from Gram-negative strains such as Escherichia coli. Also, use of B. subtilis as a host may aid in the development of either live or whole cell vaccines administered by antigen delivery system.