Immature monocyte-derived dendritic cells (DC) strongly express the endocytic mannose receptor (MR). Addition of a specific anti-MR mAb (clone PAM-1) for 24 h to cultures of immature DC induced phenotypical and functional maturation of the cells, assessed as up-regulation of costimulatory molecules and CD83, and chemotactic response to CCL19. A different isotype-matched anti-MR mAb (clone 19.2) had no significant effect. Engagement of MR with mAb PAM-1 induced the production of the anti-inflammatory cytokines IL-10, IL-1R antagonist, and of the nonsignaling IL-1R type II. In contrast IL-1β, TNF, and IL-12 were not produced. PAM-1-treated DC were unable to polarize Th1 effector cells and did not secrete the chemokines CXCL10 and CCL19; in turn, they produced large amounts of CCL22 and CCL17, thus favoring the amplification of Th2 circuits. T cells cocultured with PAM-1-matured DC initially proliferated but later became anergic and behaved as suppressor/regulatory cells. Natural ligands binding to MR had differential effects. MUC III (a partially purified mucin), biglycan (a purified complex proteoglycan), and mannosylated lipoarabinomannan from Mycobacterium tuberculosis affected cytokine production with high IL-10, IL-1R antagonist, IL-1R type II, and inhibition of IL-12. In contrast, mannan, dextran, and thyroglobulin had no significant effect. In conclusion, the appropriate engagement of the MR by mAb PAM-1 and selected natural ligands elicit a secretory program in mono-derived DC characterized by a distinct profile of cytokines/chemokines with the ability to dampen inflammation and to inhibit the generation of Th1-polarized immune responses.

Macrophage‐derived chemokine (MDC)/CCL22 is a CC chemokine active on dendritic cells (DC), NK cells and Th2 lymphocytes. The present study was aimed at comprehensively investigating MDC production in vitro and in vivo. DC were the most potent producers of MDC among leukocytes tested. Endothelial cells did not produce MDC under a variety of conditions. Signals that induce maturation (lipopolysaccharide, IL‐1, TNF, CD40 ligand, recognition of bacteria and yeast) dramatically augmented MDC production, and dexamethasone and vitamin D3 blocked it. Prostaglandin E2, which blocked the acquisition of IL‐12 production and the capacity to promote Th1 generation, did not affect MDC production. Using mass spectrometry‐based techniques, DC supernatants were found to contain N‐terminally truncated forms of MDC [MDC(3–69), MDC(5–69) and MD(C7–69)] as well as the full‐length molecule. In vivo, CD1a+, CD83+, MDC+ DC were found in reactive lymph nodes, and in Langerhans' cell histiocytosis. Skin lesions of atopic dermatitis patients showed that CD1a+ or CD1b+ DC, and DC with a CD83+ phenotype were responsible for MDC production in this Th2‐oriented disorder. Thus, DC are the predominant source of MDC in vitro and in vivo under a variety of experimental and clinical conditions. Processing of MDC to MDC(3–69) and shorter forms which do not recognize CCR4 is likely to represent a feedback mechanism of negative regulation.

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Ac cu mu la ti ng evi den ce shows that chro nic in fl am ma tion is as so cia ted to in crea sed ri sk of can cer. An in fl am ma to ry com po ne nt is pre se nt al so in the mic roen vi ron me nt of tu mou rs epi de mio lo gi cal ly un re la ted to in fl am ma tion. Exten si ve in ves ti ga tio ns over the pa st de ca de ha ve un co ve red ma ny of the im por ta nt mec ha nis tic pat hways un der lyi ng can ce r-re la ted in fl am ma tion. Pat hways lin ki ng in fl am ma tion and can cer ha ve been iden ti fi ed: an in trin sic one (dri ven by ge ne tic even ts that cau se neop la sia) and an extrin sic one (dri ven by in fl am ma to ry con di tio ns whi ch pre dis po se to can cer). Smoul de ri ng in fl am ma tion is a com po ne nt of the tu mour mic roen vi ron me nt and is a re cog ni zed hal lma rk of can cer. Key or ches tra to rs at the in tersec tion of the in trin sic and extrin sic pat hways in clu de tran scrip tion fac to rs (e.g. Nuc lear Fac tor kap pa-B, NFκB) that mo du la te the in fl am ma to ry res pon se throu gh so lub le me dia to rs (cyto ki nes, che mo ki nes) and cel lu lar com po nen ts (e.g. tu mo r-as so cia ted mac rop ha ges), pro mo ti ng tu mo ri gene sis. NFκB aids in the pro li fe ra tion and sur vi val of ma lig na nt cel ls, pro mo tes an gio ge ne sis and me tas ta sis, sub ver ts adap ti ve im mu ni ty, and al te rs res pon ses to hor mo nes and che mot he ra peu tic agen ts. Emer gi ng evi den ce al so sug ges ts that per sis te nt in fl am ma tion pro mo tes ge ne tic in sta bi li ty. Thus, can ce r-re la ted in fl am ma tion rep re sen ts a tar get for in no va ti ve diag nos tic and the ra peu tic stra te gies. Key wor ds: can ce r-re la ted in fl am ma tion; cyto ki nes; che mo ki nes; mac rop ha ges Re cei ved: July 29, 2011 Ac cep ted: Septem ber 19, 2011 Mo le cu lar pat hways in can ce r-re la ted in fl am ma tion In tro duc tionThe Ger man Pat ho lo gi st Vir chow is cre di ted wi th sug ges ti ng the ca sual li nk be tween in fl am ma tion and can cer in the 19 th cen tu ry (1). This con clu sion was ba sed on the ob ser va tion that tu mou rs of ten de ve lo ped in the set ti ng of chro nic in fl am ma tion and that in fl am ma to ry cel ls we re pre se nt in tumour biop sy spe ci me ns. Epi de mio lo gi cal stu dies ha ve re vea led that chro nic in fl am ma tion pre dis poses to diff e re nt types of can cer. It is es ti ma ted that un der lyi ng in fec tio ns and in fl am ma to ry res pon ses are lin ked to 15-20% of all dea th from can cer worldwi de (2,3). The trig ge rs of chro nic in fl am ma tion whi ch in crea se can cer ri sk in clu de mic ro bial in fectio ns (e.g. He li co bac ter pylo ri for gas tric can cer and mu co sal lympho ma), au toim mu ne di sea ses (e.g. in fl am ma to ry bowel di sea se for co lon can cer), and crypto ge nic in fl am ma to ry con di tio ns of un cer tain ori gin (e.g. pros ta ti tis for pros ta te can cer). The stron ge st evi den ce in hu ma ns of the ro le of infl am ma tion in can cer has been pro vi ded by s...

Gene‐targeted mice were used to evaluate the role of the gamma isoform of phosphoinositide 3‐kinase (PI3Kγ) in dendritic cell (DC) migration and induction of specific T‐cell‐mediated immune responses. DC obtained from PI3Kγ−/− mice showed a reduced ability to respond to chemokines in vitro and ex vivo and to travel to draining lymph nodes under inflammatory conditions. PI3Kγ−/− mice had a selective defect in the number of skin Langerhans cells and in lymph node CD8α− DC. Furthermore, PI3Kγ−/− mice showed a defective capacity to mount contact hypersensitivity and delayed‐type hypersensitivity reactions. This defect was directly related to the reduced ability of antigen‐loaded DC to migrate from the periphery to draining lymph nodes. Thus, PI3Kγ plays a nonredundant role in DC trafficking and in the activation of specific immunity. Therefore, PI3Kγ may be considered a new target to control exaggerated immune reactions.

Junctional adhesion molecule-A (JAM-A) is a transmembrane adhesive protein expressed at endothelial junctions and in leukocytes. In the present work, we found that DCs also express JAM-A. To evaluate the biological relevance of this observation, Jam-A(-/-) mice were generated and the functional behavior of DCs in vitro and in vivo was studied. In vitro, Jam-A(-/-) DCs showed a selective increase in random motility and in the capacity to transmigrate across lymphatic endothelial cells. In vivo, Jam-A(-/-) mice showed enhanced DC migration to lymph nodes, which was not observed in mice with endothelium-restricted deficiency of the protein. Furthermore, increased DC migration to lymph nodes was associated with enhanced contact hypersensitivity (CHS). Adoptive transfer experiments showed that JAM-A-deficient DCs elicited increased CHS in Jam-A(+/+) mice, further supporting the concept of a DC-specific effect. Thus, we identified here a novel, non-redundant role of JAM-A in controlling DC motility, trafficking to lymph nodes, and activation of specific immunity.

Trafficking of dendritic cells (DCs) to peripheral tissues and to secondary lymphoid organs depends on chemokines and lipid mediators. Here, we show that bone marrow-derived DCs (BM-DCs) express functional leukotriene B 4 (LTB 4 ) receptors as observed in dose-dependent chemotaxis and calcium mobilization responses. LTB 4 , at low concentrations, promoted the migration of immature and mature DCs to CCL19 and CCL21, which was associated with a rapid (30-minute) increase of CCR7 expression at the mem- IntroductionDendritic cells (DCs) play a unique role in the activation of antigen-specific naive T lymphocytes. 1,2 To perform this function, antigen-loaded DCs travel from peripheral tissues to lymph nodes. This migration is dependent on the expression of CCR7 by DCs and the production of CCR7 ligands, namely CCL19, by stromal cells and mature DCs in the lymph node and CCL21 by afferent lymphatic cells. [3][4][5][6][7] However, the expression of CCR7 is not sufficient to ensure the migration of mature DCs. [8][9][10] Experimental evidence generated in vitro and in vivo has shown that CCR7 function is dependent on the presence of costimulatory signals, including cysteinyl-leukotrienes and their membrane transporter (MRP1), as well as prostaglandin E 2 . 9,10 These results indicate that in vivo, the local inflammatory microenvironment acts critically in regulating the migration of maturing DCs. Inflammatory cytokines and microbial agents are known to induce phospholipid metabolism and the activation of arachidonic acid cascade. 11 Leukotriene B 4 (LTB 4 ) is a potent chemoattractant generated by sequential actions of cytosolic phospholipase A 2 , 5-lipoxygenase and leukotriene A 4 hydrolase on membrane phospholipids. 11,12 Previous studies have shown that LTB 4 is a mediator of innate immunity, based on its chemotactic effect for phagocytic leukocytes. 13,14 Two distinct G protein-coupled receptors, the high affinity BLT1 15 and the low affinity BLT2, 16 have been identified as LTB 4 receptors. In this study, we show that LTB 4 is also a key mediator of adaptive immunity through the regulation of DC migration to secondary lymphoid organs. Materials and methodsAll animal studies and procedures were approved by the Animal Care and Use Committee of University of Louisville Research Resources Center. ReagentsMurine CCL3, CCL19, and CCL21 were from PeproTech (Rocky Hill, NJ). Recombinant murine granulocyte macrophage-colony-stimulating factor (rmGM-CSF), human Fms-like kinase-3 (Flt-3) ligand (hFlt3L), and recombinant murine tumor necrosis factor ␣ (rmTNF-␣) were from R&D Systems (Minneapolis, MN). Cytokines were endotoxin free as assessed by Limulus amebocyte assay (BioWhittaker, Walkersville. MD). LTB 4 was purchased from Cayman Chemical (Ann Arbor, MI). Dendritic cell cultureBLT1 Ϫ/Ϫ and BLT1/2 Ϫ/Ϫ17 mice backcrossed onto B6 background for 7 generations and C57/B6 mice from the National Cancer Institute (NCI) (wild-type [WT]) were used at 8 to 12 weeks of age. CD34 ϩ -derived myeloid DCs were generated by positive i...

IntroductionDendritic cells (DCs) are professional antigen-presenting cells and key regulators of T-cell functions. 1,2 In the airway epithelium, DCs form an extensive network, where they continuously sense environmental antigens. After antigen capture, lung DCs migrate to mediastinal lymph nodes, where antigens are presented to T cells. Activation of a T helper cell 2 (Th2)-skewed response by airway DCs is responsible for allergic immune responses in the lung. 3,4 Chemokine receptors play a crucial role in the migration of maturing DCs to secondary lymphoid organs, 5,6 and several studies have shown that this process is a crucial event for the appropriate activation of the immune response. 7-10 DC migration to lymph nodes relies on the functional expression of CCR7 5,6 as well as other chemotactic receptors, such as CCR8 and BLT1. [9][10][11] In addition, lung DC migration is also regulated by PD1, one of the 2 PGD2 receptors, and by the transcription factors PPR␥ and Runx3. [12][13][14] However, as a difference from DCs localized in other anatomical compartments, the homing of lung DCs to lymph nodes is independent of the action of MRP1, the LTC4 transporter that regulates CCR7 functions. 11 This finding indicates that DC trafficking is regulated in a tissue-specific manner.Chemokine CC motif receptor-like 2 (CCRL2), also known as L-CCR (lipopolysaccharide [LPS]-inducible CC chemokinerelated gene and Eo1), is a heptahelic serpentine receptor that shares the highest homology with the chemokine receptors, CCR1 and CCR5. CCRL2 is structurally characterized by the presence of a noncanonical DRYLAIV motif. CCRL2 was originally identified in the mouse macrophage cell line RAW 264.7 15 and was recently reported to bind the chemotactic protein chemerin, though in the absence of any detectable intracellular signaling. 16 CCRL2 expression at the mRNA level has been described in murine macrophages, 15 glial cells, astrocytes, and microglia stimulated with LPS 17,18 and in mast cells. 16 CCRL2 was also reported to be up-regulated in lung macrophages and epithelial cells after in vivo sensitization. 19 The human gene most closely related to CCRL2 is HCR with its 2 splicing variants, CRAM-A and CRAM-B.Here, we describe that CCRL2 is rapidly induced during mouse DC maturation with a kinetics that precedes CCR7 induction. To evaluate the relevance of this receptor in DC biology, we generated CCRL2-deficient mice and used them in an established model of allergen-induced airway inflammation, in which DCs are known to play a crucial role. 20 The results reported here highlight a nonredundant role for CCRL2 in the migration of lung DCs to regional lymph nodes and in the induction of Th2-oriented airway allergic inflammation. These results propose CCRL2 as a new potential target for therapeutic strategies aimed at controlling lung hypersensitivity. The online version of this article contains a data supplement.The publication costs of this article were defrayed in part by page charge payment. Therefore, and solely to indicate this ...