CD103+CD11b− salivary gland dendritic cells have antigen cross‐presenting capacity

Dendritic cells (DCs) in lymphoid and non‐lymphoid tissues are professional antigen‐presenting cells that are essential for effective immunity and tolerance. However, the presence and characteristics of DCs in steady‐state salivary glands (SGs) currently remain unknown. We herein identified CD64^?CD11c⁺ classical DCs (cDCs) as well as CD64⁺ macrophages among CD45⁺MHC class II⁺ antigen‐presenting cells in steady‐state murine SGs. SG cDCs were divided into CD103⁺CD11b^? and CD103^?CD11b⁺ cDCs. CD103⁺CD11b^? cDCs expressed XCR1, CLEC9A, and interferon regulatory factor 8, whereas CD103^?CD11b⁺ cDCs strongly expressed CD172a. Both cDC subsets in SGs markedly expanded in response to the Flt3 ligand (Flt3L), were replenished by bone marrow‐derived precursors, and differentiated from common DC precursors, but not monocytes. Furthermore, ovalbumin‐pulsed SG CD103⁺CD11b^? cDCs induced the proliferation of naïve ovalbumin‐specific CD8⁺ T cells and production of interferon‐γ from proliferating T cells. SG CD103⁺CD11b^? cDCs expanded by Flt3L in vivo exhibited the same properties. These results indicate that bona fide cDCs reside in steady‐state murine SGs and cDCs with the CD103⁺CD11b^? phenotype possess antigen cross‐presenting capacity. Moreover, Flt3L enhances protective immunity by expanding cDCs. Taken together, SG cDCs might play an important role in maintaining immune homeostasis in the tissues.     

Interleukin‐2‐mediated inhibition of dendritic cell development correlates with decreased CD135 expression and increased monocyte/macrophage precursors

We have previously shown that interleukin-2 (IL-2) inhibits dendritic cell (DC) development from mouse bone marrow (BM) precursors stimulated with the ligand for FMS-like tyrosine kinase 3 receptor (Flt3L), and have provided evidence that this inhibition occurs at the monocyte DC precursor stage of DC development. Here, we explored the mechanism of IL-2-mediated inhibition of DC development. First, we showed that these in vitro cultures accurately model DCs that develop in vivo by comparing gene and protein expression of the three main Flt3L-induced DC subsets from the BM, CD11b⁺ and CD24⁺ conventional DCs (cDCs) and plasmacytoid DCs (pDCs) with their respective ex vivo spleen DC subsets (CD11b⁺, CD8⁺ and pDCs). Next, gene expression changes were quantified in Flt3L DC subsets that developed in the presence of IL-2. These changes included increased expression of Bcl2l11, which encodes the apoptosis-inducing protein Bim, and decreased expression of Flt3 (CD135), the receptor that initiates DC development. Interleukin-2 also significantly reduced Flt3 protein expression on all three Flt3L DC subsets, and attenuated Flt3L-induced STAT3 phosphorylation in DCs. Based on these data, we hypothesized that decreased Flt3 signalling may divert BM precursors down monocyte and macrophage lineages. Indeed, addition of IL-2 led to increases in Flt3⁻ cells, including cKit⁺ Ly6C⁺ CD11b⁻ populations consistent with the recently identified committed monocyte/macrophage progenitor. Therefore, IL-2 can inhibit DC development via decreased signalling through Flt3 and increased monocyte/macrophage development.     

A novel Flt3‐deficient HIS mouse model with selective enhancement of human DC development

Humanized mice harboring human immune systems (HIS) represent a platform to study immune responses against pathogens and to screen vaccine candidates and novel immunotherapeutics. Innate and adaptive immune responses are suboptimal in HIS mice, possibly due to poor reconstitution of human antigen‐presenting cells, including dendritic cells (DCs). DC homeostasis is regulated by cytokine availability, and Flt3‐ligand (Flt3L) is one factor that conditions this process. Mouse myelopoiesis is essentially normal in most current HIS models. As such, developing mouse myeloid cells may limit human DC reconstitution by reducing available Flt3L and by cellular competition for specific “niches.” To address these issues, we created a novel HIS model that compromises host myeloid cell development via deficiency in the receptor tyrosine kinase Flk2/Flt3. In Balb/c Rag2^?/?Il2rg^?/?Flt3^?/? (BRGF) recipients, human conventional DCs and plasmacytoid DCs develop from hCD34⁺ precursors and can be specifically boosted with exogenous Flt3L. Human DCs that develop in this context normally respond to TLR stimulation, and improved human DC homeostasis is associated with increased numbers of human NK and T cells. This new HIS‐DC model should provide a means to dissect human DC differentiation and represents a novel platform to screen immune adjuvants and DC targeting therapies.     

HIV gag protein is efficiently cross‐presented when targeted with an antibody towards the DEC‐205 receptor in Flt3 ligand‐mobilized murine DC

DC present exogenous proteins to MHC class I‐restricted CD8⁺ T cells. This function does not require endogenous antigen synthesis within DC, providing the potential to elicit CD8⁺ T‐cell responses to immune complexes, inactivated microbes, dying cells, and proteins such as OVA. In mice, the CD8⁺ or DEC‐205⁺ DC are specialized for cross‐presentation, and this subset can be increased 10‐fold in numbers following Fms‐like tyrosine kinase 3 ligand (Flt3L) treatment in vivo. Therefore, we studied cross‐presentation by abundant Flt3L DC using HIV gag protein. When enriched by positive selection with anti‐CD11c beads, cells from Flt3L mice are not only more abundant but are also more highly enriched in CD11c^high DC, particularly the DEC‐205⁺ subset. DC cross‐present HIV gag to primed CD8⁺ T cells, but when the antigen is delivered within an antibody to DEC‐205 receptor, cross‐presentation becomes 100‐fold more efficient than non‐targeted antigen. This finding requires gag to be engineered into anti‐DEC antibody, not just mixed with antibody. Flt3L DC are a valuable tool to study cross‐presentation, since their use overcomes the obstacle posed by the low number of cross‐presenting DC in the steady state. These findings support future experiments to use Flt3L to enhance presentation of DC‐targeted vaccines.     

The inflammatory cytokine,GM‐CSF,alters the developmental outcome of murine dendritic cells

Fms‐like tyrosine kinase 3 ligand (Flt3L) is a major cytokine that drives development of dendritic cells (DCs) under steady state, whereas GM‐CSF becomes a prominent influence on differentiation during inflammation. The influence GM‐CSF exerts on Flt3L‐induced DC development has not been thoroughly examined. Here, we report that GM‐CSF alters Flt3L‐induced DC development. When BM cells were cultured with both Flt3L and GM‐CSF, few CD8+ equivalent DCs or plasmacytoid DCs developed compared to cultures supplemented with Flt3L alone. The disappearance of these two cell subsets in GM‐CSF + Flt3L culture was not a result of simple inhibition of their development, but a diversion of the original differentiation trajectory to form a new cell population. As a consequence, both DC progeny and their functions were altered. The effect of GM‐CSF on DC subset development was confirmed in vivo. First, the CD8+ DC numbers were increased under GM‐CSF deficiency (when either GM‐CSF or its receptor was ablated). Second, this population was decreased under GM‐CSF hyperexpression (by transgenesis or by Listeria infection). Our finding that GM‐CSF dominantly changes the regulation of DC development in vitro and in vivo has important implications for inflammatory diseases or GM‐CSF therapy.     

Origin and development of dendritic cells

Summary: Dendritic cells (DCs) are specialized antigen-presenting cells and essential mediators of immunity and tolerance. This group of cells is heterogeneous in terms of cell-surface markers, anatomic location, and function. Here, we review the development and function of DCs found in lymphoid and non-lymphoid tissues in the steady state. DC and monocyte lineages originate from a common progenitor, the monocyte and dendritic cell progenitor (MDP). The two cell types diverge when MDPs give rise to monocytes and committed DC progenitors (CDPs) in the bone marrow. CDPs give rise to pre-DCs, which migrate from the bone marrow to lymphoid and non-lymphoid tissues to produce the two major subpopulations of lymphoid tissue DCs and non-lymphoid tissue CD103⁺ DCs. Within tissues and during development, DC division and homeostasis are regulated by the hormone Flt3L.     

Differential requirements of CD4+ T‐cell signals for effector cytotoxic T‐lymphocyte (CTL) priming and functional memory CTL development at higher CD8+ T‐cell precursor frequency

Increased CD8⁺ T‐cell precursor frequency (PF) precludes the requirement of CD4⁺ helper T (Th) cells for primary CD8⁺ cytotoxic T‐lymphocyte (CTL) responses. However, the key questions of whether unhelped CTLs generated at higher PF are functional effectors, and whether unhelped CTLs can differentiate into functional memory cells at higher PF are unclear. In this study, ovalbumin (OVA) ‐pulsed dendritic cells (DC_OVA) derived from C57BL/6, CD40 knockout (CD40^?/?) or CD40 ligand knockout (CD40L^?/?) mice were used to immunize C57BL/6, Ia^b?/?, CD40^?/? or CD40L^?/? mice, whose PF was previously increased with transfer of 1 × 10⁶ CD8⁺ T cells derived from OVA‐specific T‐cell receptor (TCR) transgenic OTI, OTI(CD40^?/?) or OTI(CD40L^?/?) mice. All the immunized mice were then assessed for effector and memory CTL responses. Following DC immunization, relatively comparable CTL priming occurred without CD4⁺ T‐cell help and Th‐provided CD40/CD40L signalling. In addition, the unhelped CTLs were functional effectors capable of inducing therapeutic immunity against established OVA‐expressing tumours. In contrast, the functional memory development of CTLs was severely impaired in the absence of CD4⁺ T‐cell help and CD40/CD40L signalling. Finally, unhelped memory CTLs failed to protect mice against lethal tumour challenge. Taken together, these results demonstrate that CD4⁺ T‐cell help at higher PF, is not required for effector CTL priming, but is required for functional memory CTL development against cancer. Our data may impact the development of novel preventive and therapeutic approaches in cancer patients with compromised CD4⁺ T‐cell functions.     

CD4+ T‐cell activation is differentially modulated by bacteria‐primed dendritic cells,but is generally down‐regulated by n‐3 polyunsaturated fatty acids

Appropriate activation of CD4⁺ T cells is fundamental for efficient initiation and progression of acquired immune responses. Here, we showed that CD4⁺ T‐cell activation is dependent on changes in membrane n‐3 polyunsaturated fatty acids (PUFAs) and is dynamically regulated by the type of signals provided by dendritic cells (DCs). Upon interaction with DCs primed by different concentrations and species of gut bacteria, CD4⁺ T cells were activated according to the type of DC stimulus. The levels of CD80 were found to correlate to the levels of expression of CD28 and to the proliferation of CD4⁺ T cells, while the presence of CD40 and CD86 on DCs inversely affected inducible costimulator (ICOS) and cytotoxic T‐lymphocyte antigen‐4 (CTLA‐4) levels in CD4⁺ T cells. For all DC stimuli, cells high in n‐3 PUFAs showed reduced ability to respond to CD28 stimulation, to proliferate, and to express ICOS and CTLA‐4. Diminished T‐cell receptor (TCR) and CD28 signalling was found to be responsible for n‐3 PUFA effects. Thus, the dietary fatty acid composition influences the overall level of CD4⁺ T‐cell activation induced by DCs, while the priming effect of the DC stimuli modulates CD80, CD86 and CD40 levels, thereby affecting and shaping activation of acquired immunity by differential regulation of proliferation and costimulatory molecule expression in CD4⁺ T cells.     

DC‐induced CD8+ T‐cell response is inhibited by MHC class II‐dependent DX5+CD4+ Treg

CD4⁺ T cells are important for CD8⁺ T‐cell priming by providing cognate signals for DC maturation. We analyzed the capacity of CD4⁺ T cells to influence CD8⁺ T‐cell responses induced by activated DC. Surprisingly, mice depleted for CD4⁺ cells were able to generate stronger antigen‐specific CD8⁺ T‐cell responses after DC vaccination than non‐depleted mice. The same observation was made when mice were vaccinated with MHC class II^?/? DC, indicating the presence of a MHC class II‐dependent CD4⁺ T‐cell population inhibiting CD8⁺ T‐cell responses. Recently we described the expansion of DX5⁺CD4⁺ T cells, a T‐cell population displaying immune regulatory properties, upon vaccination with DC. Intriguingly, we now observe an inverse correlation between CD8⁺ T‐cell induction and expansion of DX5⁺CD4⁺ T cells as the latter cells did not expand after vaccination with MHC class II^?/? DC. In vitro, DX5⁺CD4⁺ T cells were able to limit proliferation, modulate cytokine production and induce Foxp3⁺ expression in OVA‐specific CD8⁺ T cells. Together, our data show an inhibitory role of CD4⁺ T cells on the induction of CD8⁺ T‐cell responses by activated DC and indicate the involvement of DX5⁺CD4⁺, but not CD4⁺CD25⁺, T cells in this process.     

Cross‐presenting dendritic cells are required for control of Leishmania major infection

Leishmania major infection induces self‐healing cutaneous lesions in C57BL/6 mice. Both IL‐12 and IFN‐γ are essential for the control of infection. We infected Jun dimerization protein p21SNFT (Batf3 ^?/? ) mice (C57BL/6 background) that lack the major IL‐12 producing and cross‐presenting CD8α⁺ and CD103⁺ DC subsets. Batf3^?/? mice displayed enhanced susceptibility with larger lesions and higher parasite burden. Additionally, cells from draining lymph nodes of infected Batf3^?/? mice secreted less IFN‐γ, but more Th2‐ and Th17‐type cytokines, mirrored by increased serum IgE and Leishmania‐specific immunoglobulin 1 (Th2 indicating). Importantly, CD8α⁺ DCs isolated from lymph nodes of L. major‐infected mice induced significantly more IFN‐γ secretion by L. major‐stimulated immune T cells than CD103⁺ DCs. We next developed CD11c‐diptheria toxin receptor: Batf3^?/? mixed bone marrow chimeras to determine when the DCs are important for the control of infection. Mice depleted of Batf‐3‐dependent DCs from day 17 or wild‐type mice depleted of cross‐presenting DCs from 17–19 days after infection maintained significantly larger lesions similar to mice whose Batf‐3‐dependent DCs were depleted from the onset of infection. Thus, we have identified a crucial role for Batf‐3‐dependent DCs in protection against L. major.     

Mammalian target of rapamycin controls dendritic cell development downstream of Flt3 ligand signaling

Dendritic cells (DCs) comprise distinct functional subsets including CD8? and CD8(+) classical DCs (cDCs) and interferon-secreting plasmacytoid DCs (pDCs). The cytokine Flt3 ligand (Flt3L) controls the development of DCs and is particularly important for the pDC and CD8(+) cDC and their CD103(+) tissue counterparts. We report that mammalian target of rapamycin (mTOR) inhibitor rapamycin impaired Flt3L-driven DC development in vitro, with the pDCs and CD8(+)-like cDCs most profoundly affected. Conversely, deletion of the phosphoinositide 3-kinase (PI3K)-mTOR negative regulator Pten facilitated Flt3L-driven DC development in culture. DC-specific Pten targeting in vivo caused the expansion of CD8(+) and CD103(+) cDC numbers, which was reversible by rapamycin. The increased CD8(+) cDC numbers caused by Pten deletion correlated with increased susceptibility to the intracellular pathogen Listeria. Thus, PI3K-mTOR signaling downstream of Flt3L controls DC development, and its restriction by Pten ensures optimal DC pool size and subset composition.     

Compartmentalization of dendritic cell and T‐cell interactions in the lymph node: Anatomy of T‐cell fate decisions

Upon receiving cognate and co‐stimulatory priming signals from antigen (Ag)‐presenting dendritic cells (DCs) in secondary lymphoid tissues, naïve CD4⁺ T cells differentiate into distinct effector and memory populations. These alternate cell fate decisions, which ultimately control the T‐cell functional attributes, are dictated by programming signals provided by Ag‐bearing DCs and by other cells that are present in the microenvironment in which T‐cell priming occurs. We know that DCs can be subdivided into multiple populations and that the various DC subsets exhibit differential capacities to initiate development of the different CD4⁺ T‐helper populations. What is less well understood is why different subanatomic regions of secondary lymphoid tissues are colonized by distinct populations of Ag‐presenting DCs and how the location of these DCs influences the type of T‐cell response that will be generated. Here we review how chemokine receptors and their ligands, which position allergen and nematode‐activated DCs within different microdomains of secondary lymphoid tissues, contribute to the establishment of IL‐4 committed follicular helper T and type 2 helper cell responses.     

Lactobacillus crispatus strain SJ‐3C‐US induces human dendritic cells (DCs) maturation and confers an anti‐inflammatory phenotype to DCs

Lactobacillus crispatus is one of the most predominant species in the healthy vagina microbiota. Nevertheless, the interactions between this commensal bacterium and the immune system are largely unknown. Given the importance of the dendritic cells (DCs) in the regulation of the immunity, this study was performed to elucidate the influence of vaginal isolated L. crispatus SJ‐3C‐US from healthy Iranian women on DCs, either directly by exposure of DCs to ultraviolet‐inactivated (UVI) and heat‐killed (HK) L. crispatus SJ‐3C‐US or indirectly to its cell‐free supernatant (CFS), and the outcomes of immune response. In this work we showed that L. crispatus SJ‐3C‐US induced strong dose‐dependent activation of dendritic cells and production of high levels of IL‐10, whereas IL‐12p70 production was induced at low level in an inverse dose‐dependent manner. This stimulation skewed T cells polarization toward CD4⁺ CD25⁺ FOXP3⁺ Treg cells and production of IL‐10 in a dose‐dependent manner in mixed leukocyte reaction (MLR) test. The mode of bacterial inactivation did not affect the DCs activation pattern, upon encounter with L. crispatus SJ‐3C‐US. Moreover, while DCs stimulated with CFS showed moderate phenotypic maturation and IL‐10 production, it failed to skew T cells polarization toward CD4⁺ CD25⁺ FOXP3⁺ regulatory T cells (Treg) and production of IL‐10. This study showed that L. crispatus SJ‐3C‐US confers an anti‐inflammatory phenotype to DCs through up‐regulation of anti‐inflammatory/regulatory IL‐10 cytokine production and induction of CD4⁺ CD25⁺ FOXP3⁺ T cells at optimal dosage. Our findings suggest that L. crispatus SJ‐3C‐US could be a potent candidate as protective probiotic against human immune‐mediated pathologies, such as chronic inflammation, vaginitis or pelvic inflammatory disease (PID).     

Butyrate and retinoic acid imprint mucosal‐like dendritic cell development synergistically from bone marrow cells

Accumulating data show that the phenotypes and functions of distinctive mucosal dendritic cells (DCs) in the gut are regulated by retinoic acid (RA). Unfortunately, the exact role of butyrate in RA‐mediated mucosal DC differentiation has not been elucidated thoroughly to date. Mucosal‐like dendritic cell differentiation was completed in vitro by culturing bone marrow cells with growth factors [granulocyte–macrophage colony‐stimulating factor (GM‐CSF/interleukin (IL)‐4], RA and/or butyrate. The phenotypes, cytokine secretion, immune functions and levels of retinal dehydrogenase of different DCs were detected using quantitative polymerase chain reaction (qPCR), enzyme‐linked immunosorbent assay (ELISA) and flow cytometry, respectively. The results showed that RA‐induced DCs (RA‐DCs) showed mucosal DC properties, including expression of CD103 and gut homing receptor α₄β₇, low proinflammatory cytokine secretion and low priming capability to antigen‐specific CD4⁺ T cells. Butyrate‐treated RA‐DCs (Bu‐RA‐DCs) decreased CD11c, but increased CD103 and α₄β₇ expression. Moreover, the CD4⁺ T priming capability and the levels of retinal dehydrogenase of RA‐DCs were suppressed significantly by butyrate. Thus, butyrate and retinoic acid have different but synergistic regulatory functions on mucosal DC differentiation, indicating that immune homeostasis in the gut depends largely upon RA and butyrate to imprint different mucosal DC subsets, both individually and collectively.     

IL‐10 promotes homeostatic proliferation of human CD8+ memory T cells and,when produced by CD1c+ DCs,shapes naive CD8+ T‐cell priming

IL‐10 is an anti‐inflammatory cytokine that inhibits maturation and cytokine production of dendritic cells (DCs). Although mature DCs have the unique capacity to prime CD8⁺ CTL, IL‐10 can promote CTL responses. To understand these paradoxic findings, we analyzed the role of IL‐10 produced by human APC subsets in T‐cell responses. IL‐10 production was restricted to CD1c⁺ DCs and CD14⁺ monocytes. Interestingly, it was differentially regulated, since R848 induced IL‐10 in DCs, but inhibited IL‐10 in monocytes. Autocrine IL‐10 had only a weak inhibitory effect on DC maturation, cytokine production, and CTL priming with high‐affinity peptides. Nevertheless, it completely blocked cross‐priming and priming with low‐affinity peptides of a self/tumor‐antigen. IL‐10 also inhibited CD1c⁺ DC‐induced CD4⁺ T‐cell priming and enhanced Foxp3 induction, but was insufficient to induce T‐cell IL‐10 production. CD1c⁺ DC‐derived IL‐10 had also no effect on DC‐induced secondary expansions of memory CTL. However, IL‐15‐driven, TCR‐independent proliferation of memory CTL was enhanced by IL‐10. We conclude that DC‐derived IL‐10 selects high‐affinity CTL upon priming. Moreover, IL‐10 preserves established CTL memory by enhancing IL‐15‐dependent homeostatic proliferation. These combined effects on CTL priming and memory maintenance provide a plausible mechanism how IL‐10 promotes CTL responses in humans.     

Fms-like tyrosine kinase 3 ligand-dependent dendritic cells in autoimmune inflammation

Dendritic cells (DCs) are specialized in capture, processing and presentation of antigens to T cells. Depending on the type of DC and its activation state, the interaction of DCs with naive T cells can lead to different types of immune response, or to T-cell tolerance. The existence of many specialized subtypes of DCs with particular functions has raised the need to distinguish DCs formed in steady-state from those produced during an inflammatory response. In patients with autoimmune disease and in experimental animal models of autoimmunity, DCs show abnormalities in both numbers and activation state, expressing immunogenic levels of co-stimulatory molecules and pro-inflammatory cytokines. Initial in vitro studies of cytokines in DC development revealed distinct and important roles for the receptor tyrosine kinases, granulocyte-macrophage colony-stimulating factor (GM-CSF), macrophage colony-stimulating factor (M-CSF, also called CSF1) and fms-like tyrosine kinase 3 ligand (Flt3L) in the generation of DCs. Flt3L is critical for instructing DC generation throughout different organs and regulates DC development from Flt3⁺ lymphoid and myeloid-committed progenitors to DCs in vivo. The aim of this review is to provide an overview of the role of Flt3L-dependent DCs in the immunopathogenesis of autoimmunity and chronic inflammation and its potential as therapeutic targets.     

Dendritic cell SIRPα regulates homeostasis of dendritic cells in lymphoid organs

Signal regulatory protein α (SIRPα), an immunoglobulin superfamily protein that is expressed predominantly in myeloid lineage cells such as dendritic cells (DCs) or macrophages, mediates cell–cell signaling. In the immune system, SIRPα is thought to be important for homeostasis of DCs, but it remains unclear whether SIRPα intrinsic to DCs is indeed indispensable for such functional role. Thus, we here generated the mice, in which SIRPα was specifically ablated in CD11c⁺ DCs (Sirpa^ΔDC). Sirpa^ΔDC mice manifested a marked reduction of CD4⁺ CD8α^– conventional DCs (cDCs) in the secondary lymphoid organs, as well as of Langerhans cells in the epidermis. Such reduction of cDCs in Sirpa^ΔDC mice was comparable to that apparent with the mice, in which SIRPα was systemically ablated. Expression of SIRPα in DCs was well correlated with that of either endothelial cell‐selective adhesion molecule (ESAM) or Epstein–Barr virus‐induced molecule 2 (EBI2), both of which were also implicated in the regulation of DC homeostasis. Indeed, ESAM⁺ or EBI2⁺ cDCs were markedly reduced in the spleen of Sirpa^ΔDC mice. Thus, our results suggest that SIRPα intrinsic to CD11c⁺ DCs is essential for homeostasis of cDCs in the secondary lymphoid organs and skin.     

Migratory properties of pulmonary dendritic cells are determined by their developmental lineage

The chemokine receptor, CCR7, directs the migration of dendritic cells (DCs) from peripheral tissue to draining lymph nodes (LNs). However, it is unknown whether all pulmonary DCs possess migratory potential. Using novel Ccr7^gfp reporter mice, we found that Ccr7 is expressed in CD103⁺ and a CD14^med/lo subset of CD11b^hi classical (c)DCs but not in monocyte-derived (mo)DCs, including Ly-6C^hiCD11b^hi inflammatory DCs and CD14^hiCD11b^hi DCs. Consequently, cDCs migrated to lung-draining LNs but moDCs did not. Mice lacking the chemokine receptor, CCR2, also lacked inflammatory DCs in the lung after lipopolysaccharide inhalation but retained normal levels of migratory DCs. Conversely, the lungs of fms-like tyrosine kinase 3 ligand (Flt3L)-deficient mice lacked cDCs but retained moDCs, which were functionally mature but did not express Ccr7 and were uniformly non-migratory. Thus, the migratory properties of pulmonary DCs are determined by their developmental lineage.