Abstract
It has been postulated that low-level interleukin (IL)-12 production of antigen-presenting cells is associated with the risk of developing atopic asthma. To study the relationship between IL-12 production capacity of dendritic cells (DCs) and development of T helper type 2 (Th2) responses in the lung, we genetically engineered DCs to constutively overexpress bioactive IL-12. Retrovirally mediated overexpression of IL-12 in DCs strongly polarized naive ovalbumin (OVA)-specific CD4+ T cells toward Th1 effector cells in vitro. After intratracheal injection, OVA-pulsed IL-12-overexpressing DCs failed to induce Th2 responses in vivo and no longer primed mice for Th2-dependent eosinophilic airway inflammation upon OVA aerosol challenge, readily observed in mice immunized with sham-transfected, OVA-pulsed DCs. Analysis of a panel of cytokines and chemokines in the lung demonstrated that the lack of Th2 sensitization was accompanied by increased production of the Th1 cytokine interferon-gamma (IFN-gamma), chemokines induced by IFN-gamma, and the immunoregulatory cytokine IL-10. When Th2 priming was induced using OVA/alum prior to intratracheal DC administration, DCs constitutively expressing IL-12 were no longer capable of preventing eosinophilic airway inflammation and even enhanced it. These data show directly that high-level expression of IL-12 in DCs prevents the development of Th2 sensitization. Enhancing IL-12 production in DCs should be seen as a primary prevention strategy for atopic disorders. Enhancing IL-12 production in DCs is less likely to be of benefit in already Th2-sensitized individuals.
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Disclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.