text: Acute ablation of Langerhans cells enhances skin immune responses.
  Understanding the function of Langerhans cells (LCs) in vivo has been complicated by conflicting results from LC-deficient mice. Human Langerin-DTA mice constitutively lack LCs and develop exaggerated contact hypersensitivity (CHS) responses. Murine Langerin-diphtheria toxin receptor (DTR) mice allow for the inducible elimination of LCs and Langerin(+) dermal dendritic cells (dDCs) after administration of diphtheria toxin, which results in reduced CHS. When Langerin(+) dDCs have partially repopulated the skin but LCs are still absent, CHS returns to normal. Thus, LCs appear to be suppressive in human Langerin-DTA mice and redundant in murine Langerin-DTR mice. To determine whether inducible versus constitutive LC ablation explains these results, we engineered human Langerin-DTR mice in which diphtheria toxin ablates LCs without affecting Langerin(+) dDCs. The inducible ablation of LCs in human Langerin-DTR mice resulted in increased CHS. Thus, LC-mediated suppression does not require their absence during ontogeny or during the steady-state and is consistent with a model in which LCs actively suppress Ag-specific CHS responses.
  
entities: ['Langerhans cells']
entities: Cell
entities: PMID-20855870_T1
entities: ['skin']
entities: Organ
entities: PMID-20855870_T2
entities: ['Langerhans cells']
entities: Cell
entities: PMID-20855870_T3
entities: ['LCs']
entities: Cell
entities: PMID-20855870_T4
entities: ['LC']
entities: Cell
entities: PMID-20855870_T5
entities: ['LCs']
entities: Cell
entities: PMID-20855870_T6
entities: ['LCs']
entities: Cell
entities: PMID-20855870_T7
entities: ['Langerin(+) dermal dendritic cells']
entities: Cell
entities: PMID-20855870_T8
entities: ['dDCs']
entities: Cell
entities: PMID-20855870_T9
entities: ['Langerin(+) dDCs']
entities: Cell
entities: PMID-20855870_T10
entities: ['skin']
entities: Organ
entities: PMID-20855870_T11
entities: ['LCs']
entities: Cell
entities: PMID-20855870_T12
entities: ['LCs']
entities: Cell
entities: PMID-20855870_T13
entities: ['LC']
entities: Cell
entities: PMID-20855870_T14
entities: ['LCs']
entities: Cell
entities: PMID-20855870_T15
entities: ['Langerin(+) dDCs']
entities: Cell
entities: PMID-20855870_T16
entities: ['LCs']
entities: Cell
entities: PMID-20855870_T17
entities: ['LC']
entities: Cell
entities: PMID-20855870_T18
entities: ['LCs']
entities: Cell
entities: PMID-20855870_T19