Search

To cite this article: Lu M, Dawicki W, Zhang X, Huang H, Nayyar A, Gordon JR. Therapeutic induction of tolerance by IL-10-differentiated dendritic cells in a mouse model of house dust mite-asthma. Allergy 2011; 66: 612–620. Abstract Background: It has been reported that retrovirally transduced IL-10-expressing dendritic cells can reverse the asthma phenotype in mice, but that i.v. delivery of dendritic cells differentiated with IL-10 alone (DC10) does not. We report herein DC10 can be highly effective therapeutically in experimental asthma. Methods: BALB/c mice were sensitized by airway exposure to house dust mite (HDM) without use of adjuvants, then treated with 106 allergen-presenting DC10. We assessed the airway hyperresponsiveness (AHR) to methacholine, circulating levels of IgE and IgG1, and airway recall responses to HDM allergen, including eosinophilia and Th2 cytokines. We also asked whether the DC10 treatments induced tolerance through activation of pulmonary regulatory T cell activities. Results: In vitro, cognate-, but not irrelevant-, allergen-presenting DC10 productively engaged pulmonary Th2-phenotype CD4+ cells magnetically sorted from HDM-asthmatic mice in Forster (or fluorescence) resonance energy transfer assays. In vivo, treatment of HDM-asthmatic mice with HDM, but not ovalbumin-presenting DC10 abrogated AHR within 4 weeks, and significantly reduced airway eosinophilia, IL-4, IL-5, and IL-13 responses, and circulating HDM-specific IgE and IgG1 levels (each, P ≤ 0.01 versus control mice). CD4+CD25+Foxp3+ cells from the lungs of the DC10-treated mice, but not those from asthmatic animals, up-regulated expression of the activated regulatory T cell markers CTLA4 and LAG3, and passive transfer of pulmonary CD4+ T cells from these mice induced allergen tolerance in HDM-asthmatic recipients. Conclusions: These findings indicate that allergen-presenting DC10 treatments up-regulate T cell regulatory activities and thereby induce allergen-specific tolerance in a relevant model of human asthma.

Background Allergen-presenting dendritic cells differentiated with IL-10 (DC10) reverse the asthma phenotype in mice by converting their Th2 cells to regulatory T cells (Tregs). DC10 express elevated levels of IL-10, but substantially reduced levels of MHCII and costimulatory molecules, so the relationships between these factors with each other and tolerogenicity have not been clearly elucidated. Methods We assessed the roles of these inputs in DC10 reversal of OVA-associated asthma-like disease by treating affected mice with OVA-pulsed DC10 generated from wild-type or IL-10-sufficient MHCII−/− or CD80/CD86−/− mice, or with MHCII-intact IL-10-silenced DC10. Results IL-10 silencing did not discernibly affect the cells' immunobiology (e.g., costimulatory molecules, chemokines), but it eliminated IL-10 secretion and the cell's abilities to induce tolerance, as determined by assessments of airway hyper-responsiveness, eosinophilia, and Th2 responses to recall OVA challenge. MHCII−/− DC10 expressed normal levels of IL-10, but, nevertheless, were unable to induce allergen tolerance in asthma phenotype mice, while tolerance induced by CD80/CD86−/− DC10 was attenuated but not eliminated. We also assessed the induction of multiple Treg cell markers (e.g., ICOS, PD-1, GITR) on pulmonary CD25+Foxp3+ cells in the treated mice. Wild-type DC10 treatments upregulated expression of each marker, while neither IL-10-silenced nor MHCII−/− DC10 did so, and the CD80/86−/− DC10 induced an intermediate Treg cell activation phenotype. Conclusion Both IL-10 and MCHII expression by DC10 are requisite, but not sufficient for tolerance induction, suggesting that DC10 and Th2 effector T cells must be brought together in a cognate fashion in order for their IL-10 to induce tolerance.