Batf3-Dependent CD11blow/− Peripheral Dendritic Cells Are GM-CSF-Independent and Are Not Required for Th Cell Priming after Subcutaneous Immunization

et al. (2011) Batf3-Dependent CD11blow/2 Peripheral Dendritic Cells Are GM-CSF-Independent and Are Not Required for Th Cell Priming after Subcutaneous Immunization. PLoS ONE 6(10): e25660. doi:10.1371/journal.pone.0025660 low/2 Batf3 -Dependent CD11b Peripheral Dendritic Cells Are GM-CSF-Independent and Are Not Required for Th Cell Priming after Subcutaneous Immunization Brian T. Edelson 0 1 Tara R. Bradstreet 0 1 Wumesh KC 0 1 Kai Hildne 0 1 r 0 1 Jeremy W. Herzog 0 1 Julia Sim 0 1 John H. Russell 0 1 Theresa L. Murphy 0 1 Emil R. Unanue 0 1 Kenneth M. Murphy 0 1 Charalampos Babis Spilianakis, University of Crete, Greece 0 Current address: Department of Internal Medicine, Medical Clinic 1, University of Erlangen-Nu rnberg , Erlangen , Germany 1 1 Department of Pathology and Immunology, Washington University School of Medicine , St. Louis , Missouri, United States of America, 2 Howard Hughes Medical Institute, Washington University School of Medicine , St. Louis , Missouri, United States of America, 3 Department of Developmental Biology, Washington University School of Medicine , St. Louis, Missouri , United States of America Dendritic cells (DCs) subsets differ in precursor cell of origin, functional properties, requirements for growth factors, and dependence on transcription factors. Lymphoid-tissue resident CD8a+ conventional DCs (cDCs) and CD11blow/2CD103+ non-lymphoid DCs are developmentally related, each being dependent on FMS-like tyrosine kinase 3 ligand (Flt3L), and requiring the transcription factors Batf3, Irf8, and Id2 for development. It was recently suggested that granulocyte/ macrophage colony stimulating factor (GM-CSF) was required for the development of dermal CD11blow/2Langerin+CD103+ DCs, and that this dermal DC subset was required for priming autoreactive T cells in experimental autoimmune encephalitis (EAE). Here, we compared development of peripheral tissue DCs and susceptibility to EAE in GM-CSF receptor deficient (Csf2rb2/2) and Batf32/2 mice. We find that Batf3-dependent dermal CD11blow/2Langerin+ DCs do develop in Csf2rb2/2 mice, but that they express reduced, but not absent, levels of CD103. Further, Batf32/2 mice lacking all peripheral CD11blow/2 DCs show robust Th cell priming after subcutaneous immunization and are susceptible to EAE. Our results suggest that defective T effector priming and resistance to EAE exhibited by Csf2rb2/2 mice does not result from the absence of dermal CD11blow/2Langerin+CD103+ DCs. - Funding: KMM was supported by the Howard Hughes Medical Institute (www.hhmi.org), BTE by a Burroughs Wellcome Fund Career Award for Medical Scientists (www.bwfund.org), a Jack H. Ladenson Fellowship in Experimental Clinical Pathology at Washington University School of Medicine, and an American Society of Hematology Scholar Award (www.hematology.org), KH by the Emmy Noether Program of the German Research Foundation (www.dfg.de/index.jsp), ERU by a grant from the National Institutes of Health (www.nih.gov, AI024742), and JHR by a grant from the National Multiple Sclerosis Society (www.nationalmssociety. org, RG 4352). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript. Competing Interests: The authors have declared that no competing interests exist. GM-CSF regulates the development and activity of several myeloid cell types and influences both the initiation and maintenance of adaptive immune responses [1]. Mice lacking GM-CSF or its receptor show decreased antigen specific T cell priming against the encephalitogenic peptide of myelin oligodendrocyte glycoprotein (MOG3555) and are resistant to EAE [2]. Beyond this role in priming adaptive immune responses, GM-CSF acts to sustain ongoing effector responses, both in EAE initiated by MOG3555 peptide [2] and in collagen-induced arthritis [3]. Similarly, in a murine model of autoimmune myocarditis, GMCSF acts during priming of Th17 responses by promoting IL-6 and IL-23 production from DCs and during ongoing autoimmune responses by promoting survival of autoreactive CD4+ T cells [4]. Several recent studies indicate that it is GM-CSF rather than IL-17 that is the primary Th17-derived cytokine responsible for the development of EAE [57]. Initially, it was thought that IL-17 production would explain why Th17 cells and RORct were required for EAE. However, in vivo neutralization of IL-17 only reduced EAE severity but did not eliminate disease, and non-IL-17 and non-IFN-c pathways have been implicated [810]. IL-23, but not IL-6 or TGF-b, was found to be critical for regulating the pathogenicitiy of Th17 cells [11,12]. GM-CSF derived from T cells, but not other CNS-resident or peripheral immune cells, was required for development of EAE [5], and acted during the effector phase to augment pathogenicity of Th17 cells [6,7]. IL-23 induced Th17 cells to increase production of GM-CSF, which further enhanced IL-23 production by antigen-presenting cells [6]. RORct was shown to induce GM-CSF, which acted on infiltrating myeloid cells entering the CNS, rather than resident microglia, during the development of EAE [7]. These studies suggest a model of EAE in which pathogenic T cells secrete GM-CSF that activates myeloid cells infiltrating the CNS to produce pathogenic lesions and further amplifies IL-23 production by DCs [13]. A recent report has suggested that the role for GM-CSF in EAE was based on its requirement for the development of dermal CD11blow/2Langerin+CD103+ DCs [14]. Dermal CD11blow/2 Langerin+CD103+ DCs represent one anatomic subtype of peripheral tissue CD11blow/2CD103+ DCs, all of which share with lymphoid tissue CD8a+ cDCs developmental dependence on Batf3, Irf8, and Id2 [15,16]. CD8a+ cDCs are cross-presenting DCs, characterized by consistent expression of DEC205, and variable expression of CD103 which can be regulated by GM-CSF, IL-3, and TGF-b1 [1719]. Mice lacking GM-CSF or the GM-CSF irne+cCepDto1r03+weDreCs rienpotrhteedskitno alnadckpedrieprhmearall ClyDm1p1hblnowo/d2eLsaunngdeerrsteady state and inflammatory conditions, and were resistant to EAE [14]. In addition, radiation chimeras expressing the human diphtheria toxin receptor (DTR) controlled by the Langerin promoter [20] and depleted of peripheral CD11blow/2Langerin+CD103+ DCs were resistant to EAE and had reduced priming of MOG3555 -specific T cells [14]. This study concluded that GMCSF was required for the initiation of EAE because it was required for the development of dermal CD11blow/2Langerin+CD103+ DCs, which were required to prime pathogenic T cells [14]. To test whether loss of GM-CSF receptor protects from EAE by eliminating dermal CD11blow/2Langerin+CD103+ DCs, we asked if Batf32/2 mice, which also lack this DC subset, are also protected from EAE. We find that Batf32/2 mice develop EAE after immunization and have increased numbers of MOG3555 peptidespecific T cells, excluding a requirement for either peripheral CD11blow/2CD103+ DC (...truncated)