PURPOSE: The use of tolerogenic dendritic cells (TolDCs) to control exacerbated immune responses may be a prophylactic and therapeutic option for application in autoimmune and allergic conditions. The objective of this work was to evaluate the effects of TolDC administration in a mouse model of allergic airway inflammation caused by mite extract. METHODS: Mouse bone marrow-derived TolDCs were induced by incubation with granulocyte-macrophage colony-stimulating factor (GM-CSF) and dexamethasone, and then characterized by flow cytometry and cytokine production by enzyme-linked immunosorbent assay (ELISA). For the in vivo model of Blomia tropicalis-induced allergy, mice transplanted with antigen-pulsed TolDCs were sensitized intraperitoneally with B. tropicalis mite extract (BtE) adsorbed to aluminium hydroxide. After challenge by nasal administration of BtE, bronchoalveolar lavage fluid (BALF), lungs, spleen and serum were collected for analysis. RESULTS: Induction of TolDCs was efficiently achieved as shown by low expression of major histocompatibility complex (MHC) II, programmed death-ligand (PD-L) 2 and pro-inflammatory cytokine production, and up-regulation of interleukin (IL)-10, upon LPS stimulation in vitro. Transplantation of 1 or 2 doses of BtE-pulsed TolDCs reduced the number of inflammatory cells in BALF and lungs as well as mucus deposition. Moreover, compared to saline-injected controls, TolDC-treated mice showed lower serum levels of anti-BtE immunoglobulin E (IgE) antibodies as well as reduced Gata3 and IL-4 gene expression in the lungs and decreased IFN-γ levels in the supernatant of splenocyte cultures Transplantation of TolDCs increased the percentage of the regulatory T cells in the spleen and the lungs. CONCLUSIONS: Preventive treatment with TolDCs protects against dust mite-induced allergy in a mouse model, reinforcing the use of tolerogenic dendritic cells for the management of allergic conditions.
Administration, Intranasal ; Animals ; Antibodies ; Antigens, Dermatophagoides ; Asthma ; Bronchoalveolar Lavage Fluid ; Dendritic Cells* ; Dexamethasone ; Dust* ; Enzyme-Linked Immunosorbent Assay ; Flow Cytometry ; Gene Expression ; Granulocyte-Macrophage Colony-Stimulating Factor ; Hypersensitivity ; Immunoglobulin E ; Immunoglobulins ; In Vitro Techniques ; Inflammation* ; Interleukin-4 ; Interleukins ; Lung ; Major Histocompatibility Complex ; Mice ; Mites* ; Mucus ; Spleen ; T-Lymphocytes, Regulatory ; Up-Regulation

Objective To evaluate the acaricidal activity of the essential oil obtained from roots of Derris floribunda (D. floribunda) (Miq.) Benth, and its main constituent nerolidol against the Mexican mite Tetranychus mexicanus (T. mexicanus) (McGregor). Methods The essential oil from the roots of D. floribunda collected in the Amazon region (Brazil) was obtained by hydrodistillation. Its chemical composition was determined by GC–MS analysis. The acaricidal activities of this essential oil and nerolidol, were evaluated by recording the number of dead females (mortality) and eggs (fertility). Results The essential oil showed sesquiterpenes as major volatile components. Nerolidol, the main component, represented 68.5% of the total composition of the essential oil. D. floribunda essential oil and nerolidol showed acaricidal activity, with LC