2-4-dinitrofluorobenzene-sulfonic-acid and Dermatitis--Allergic-Contact

Soyasaponins (SSs) are abundant in soybeans and display inhibitory activity against contact hypersensitivity (CHS), which is often used as a mouse model for allergic contact dermatitis (ACD); however, their therapeutic mechanisms remain unknown. Here, we attempted to clarify the role of gut microbiota in the inhibition of CHS by dietary soyasaponins. For antibiotic treatment, mice were administered a mixture of ciprofloxacin and metronidazole or vancomycin. These antibiotics and SSs were given to mice via drinking water 3-weeks prior to CHS induction with 2,4-dinitrofluorobenzene, and the mice were analysed for ear swelling, tissue oedema, infiltration of Gr-1-positive immune cells, the composition of faecal microbiota and regulatory T (T

Topics: Animals; Anti-Bacterial Agents; Cells, Cultured; Dermatitis, Allergic Contact; Dermatitis, Contact; Diet; Dinitrofluorobenzene; Disease Models, Animal; Edema; Female; Gastrointestinal Microbiome; Glycine max; Humans; Mice; Mice, Inbred BALB C; Saponins; T-Lymphocytes, Regulatory

The murine local lymph node assay (LLNA) is a validated method for identifying skin sensitization hazard. Vehicle choice can influence the sensitization potential of haptens in both the LLNA and in humans, therefore selection of an appropriate vehicle is important. Suggested vehicles for the LLNA include organic solvents and organic-aqueous mixtures. However, due to its high surface tension and poor wetting qualities, water is not recommended and therefore testing aqueous soluble materials can be problematic. The aims of this investigation were to identify a water-based vehicle that possesses better skin wetting properties than water alone, and to assess its performance relative to other solvents in the LLNA using aqueous soluble haptens. The selected wetting agent was the surfactant Pluronic(R) L92 (L92). Concentrations of L92 of up to 50% did not induce positive responses in the LLNA. 1% aqueous L92 was chosen for further examination. Dose-response analyses were performed with dinitrobenzene sulfonic acid (DNBS) and formaldehyde formulated either in water, 1% L92, dimethyl sulfoxide (DMSO) or dimethyl formamide (DMF). Potassium dichromate (PDC) and nickel sulfate were tested in 1% L92, DMSO or DMF. The highest concentration of potassium dichromate was retested in each vehicle and in water to assess the effect of the wetting agent. Estimates of the relative sensitizing potency in each vehicle were determined by calculation of EC3 values (the estimated concentration required to induce a threshold positive response). While DNBS and formaldehyde produced positive responses in all four vehicles, their relative potency varied among the vehicles. The rank ordering of potencies for both materials was, from highest to lowest, DMF > or = DMSO > 1% L92 > water. Compared with water, use of 1% L92 resulted in >2-fold increase in potency for DNBS and >3-fold increase for formaldehyde. PDC was positive in DMF, DMSO and 1% L92. The potency ranking was DMF > or = DMSO > 1% L92. Re-evaluation of 0.5% PDC confirmed that formulations of both DMSO and DMF induced strong proliferative responses, whereas somewhat less proliferation was recorded with the 1% L92 vehicle. PDC in water was without activity. The performance of 1% L92 as a vehicle for nickel sulfate was assessed relative to DMSO and DMF. In DMSO, nickel sulfate produced a stimulation index (SI) >3 at only the highest level. Testing in DMF induced low levels of proliferation, but failed to produce a SI of 3 at any c

Topics: Allergens; Animals; Dermatitis, Allergic Contact; Dimethyl Sulfoxide; Dimethylformamide; Dinitrofluorobenzene; Female; Haptens; Lipoproteins; Lymph Nodes; Lymphocyte Activation; Mice; Mice, Inbred CBA; Nickel; Potassium Dichromate; Solubility; Solvents; Water; Wetting Agents

Interleukin-17 (IL-17) is a proinflammatory cytokine produced by T cells. The involvement of IL-17 in human diseases has been suspected because of its detection in sera from asthmatic patients and synovial fluids from arthritic patients. In this study, we generated IL-17-deficient mice and investigated the role of IL-17 in various disease models. We found that contact, delayed-type, and airway hypersensitivity responses, as well as T-dependent antibody production, were significantly reduced in the mutant mice, while IL-17 deficiency of donor T cells did not affect acute graft-versus-host reaction. The results suggest that impaired responses were caused by the defects of allergen-specific T cell activation. Our findings indicate that IL-17 plays an important role in activating T cells in allergen-specific T cell-mediated immune responses.

Topics: Acute Disease; Animals; Antibody Formation; B-Lymphocytes; Bronchial Hyperreactivity; CD4-Positive T-Lymphocytes; Cells, Cultured; Coculture Techniques; Dendritic Cells; Dermatitis, Allergic Contact; Dinitrofluorobenzene; Female; Graft vs Host Reaction; Haptens; Hypersensitivity, Delayed; Immunity, Cellular; Interleukin-17; Lymphocyte Activation; Lymphocyte Cooperation; Male; Mice; Mice, Inbred BALB C; Mice, Inbred C57BL; Mice, Knockout; Mitogens; Models, Animal; Nickel; Picryl Chloride; Specific Pathogen-Free Organisms; Spleen; T-Lymphocyte Subsets; Tumor Necrosis Factor-alpha

Contact sensitivity is a T-cell-mediated immune disease that can occur when low-molecular-weight chemicals penetrate the skin. In vivo topical application of chemical sensitizers results in morphological modification of Langerhans cells (LC). Moreover, within 18 h, LC increase their major histocompatibility complex (MHC) class II antigens expression and migrate to lymph nodes where they present the sensitizer to T lymphocytes. We wanted to determine if such an effect could also be observed in vitro. However, because of the high genetic diversity encountered in humans, assays were performed with dendritic cells (DC) obtained from a Balb/c mouse strain. The capacity of a strong sensitizer, DNBS (2,4-dinitrobenzene sulfonic acid), to modulate the phenotype of bone marrow-derived DC in vitro, was investigated. A specific and marked increase of MHC class II molecules expression was observed within 18 h. To eliminate the use of animals in sensitization studies, the XS52 DC line was tested at an immature stage. A 30-min contact with the strong sensitizers DNBS and oxazolone, or the moderate mercaptobenzothiazole, resulted in upregulation of MHC class II molecules expression, analyzed after 18-h incubation. This effect was not observed with irritants (dimethyl sulfoxide and sodium lauryl sulfate) nor with a neutral molecule (sodium chloride). These data suggested the possibility of developing an in vitro model for the identification of the sensitizing potential of chemicals, using a constant and non animal-consuming material.

Topics: Animal Testing Alternatives; Animals; Antigens, CD; Antigens, Surface; Benzothiazoles; Bone Marrow Cells; Cell Adhesion; Cell Line; Cells, Cultured; Dendritic Cells; Dermatitis, Allergic Contact; Dimethyl Sulfoxide; Dinitrofluorobenzene; Female; Gene Expression Regulation; Genes, MHC Class II; Haptens; Histocompatibility Antigens Class II; Immunophenotyping; Irritants; Mice; Mice, Inbred BALB C; Oxazolone; Sodium Chloride; Sodium Dodecyl Sulfate; Thiazoles

The mechanisms underlying the induction of immunological tolerance after feeding soluble exogenous antigens, including proteins and haptens, are still unclear. Using a model of oral tolerance to the contact-sensitizing hapten 2,4-dinitrochlorobenzene (DNCB), we have compared the ability-of intestinal epithelial cells and of Peyer's patch APC to present DNCB in vitro or ex vivo after oral feeding, to specific peripheral lymph node T cells from DNCB-sensitized mice. In contrast to Peyer's patch APC, which induce efficient hapten-specific T cell activation upon exposure to the hapten either in vitro or in vivo, mature MHC class-II-positive intestinal epithelial cells were unable to induce T cell activation in either case. Interestingly, enterocytes from DNCB-fed mice exerted a dramatic inhibitory effect on the proliferative response of hapten-primed T cells in response to dinitrobenzene sulfonate presented by syngeneic spleen cells. This inhibitory effect, which was also observed with supernatant of intestinal epithelial cells from DNCB-fed mice, could be reversed by neutralizing anti-transforming growth factor (TGF)-beta antibodies. In addition, pre-incubation of hapten-sensitized T cells with enterocytes from DNCB-fed mice induced T cell anergy, which could be reversed by exogenous interleukin-2 or interleukin-4. These data demonstrate that intestinal epithelial cells activated in vivo by oral administration of DNCB are able to block proliferation of activated T cells through secretion of immunosuppressive cytokines such as TGF-beta. It is proposed that intestinal epithelial cells may play a significant role in oral tolerance by limiting T cell-mediated hypersensitivity responses.

Topics: Administration, Oral; Animals; Antigen-Presenting Cells; Culture Media, Conditioned; Dermatitis, Allergic Contact; Dinitrochlorobenzene; Dinitrofluorobenzene; Epithelial Cells; Female; Haptens; Histocompatibility Antigens Class II; Immune Tolerance; Immunization; Interleukin-2; Interleukin-4; Intestinal Absorption; Intestinal Mucosa; Lymph Nodes; Lymphocyte Activation; Mice; Mice, Inbred C3H; Peyer's Patches; Spleen; T-Lymphocyte Subsets; Transforming Growth Factor beta

The epicutaneous application of haptens results in a functional activation of the antigen-presenting Langerhans cells (LCs) which is necessary for the induction of contact sensitivity. In this ultrastructural study, we investigated the effects of the immune response on these cellular properties of the LCs by using 2 strains of guinea pigs with genetically determined high and non responsiveness, respectively, to the strong sensitizer 2,4-dinitrochlorobenzene (DNCB). After skin painting, both strains showed a similar cellular and endocytotic activation of the LCs and a similar intraepidermal localization of DNCB on immunoelectron microscopical visualization. There were however few LC-lymphoid cell interactions in the non responders, in contrast to numerous such appositions in the other strain. Intravenous tolerization with 2,4-dinitrobenzene-1-sulfonic acid, which is known to block the DNCB receptor of T cells, hampered the lymphoid cell interactions in the DNCB treated high responders, but it did not affect the LC activation. These in vivo observations demonstrate that the hapten-induced changes of the LC properties is the initial, T-cell independent event in contact sensitization.

Topics: Administration, Cutaneous; Animals; Cell Adhesion; Cyclopropanes; Dermatitis, Allergic Contact; Dinitrochlorobenzene; Dinitrofluorobenzene; Disease Susceptibility; Endocytosis; Epidermis; Female; Genetic Predisposition to Disease; Guinea Pigs; Immune Tolerance; Injections, Intravenous; Langerhans Cells; Lymphocyte Culture Test, Mixed; Microscopy, Electron; Oxazolone; T-Lymphocyte Subsets