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Stoeckle C, Sommandas V, Adamopoulou E, Belisle K, Schiekofer S, Melms A, Weber E, Driessen C, Boehm BO, Tolosa E, Burster T. Cathepsin G is differentially expressed in primary human antigen-presenting cells. Cell Immunol 2008; 255:41-5. [PMID: 19036358 DOI: 10.1016/j.cellimm.2008.10.001] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2008] [Revised: 10/06/2008] [Accepted: 10/08/2008] [Indexed: 11/18/2022]
Abstract
Cathepsins are required for the processing of antigens in order to make them suitable for loading on major histocompatibility complex (MHC) class II molecules, for subsequent presentation to CD4(+) T cells. It was shown that antigen processing in monocyte-derived dendritic cells (DC), a commonly used DC model, is different from that of primary human DC. Here, we report that the two subsets of human myeloid DC (mDC) and plasmacytoid DC (pDC) differ in their cathepsin distribution. The serine protease cathepsin G (CatG) was detected in mDC1, mDC2, pDC, cortical thymic epithelial cells (cTEC) and high levels of CatG were determined in pDC. To address the role of CatG in the processing and presentation of a Multiple Sclerosis-associated autoantigen myelin basic protein (MBP), we used a non-CatG expressing fibroblast cell line and fibroblasts, which were preloaded with purified CatG. We find that preloading fibroblasts with CatG results in a decrease of MBP84-98-specific T cell proliferation, when compared to control cells. Our data suggest a different processing signature in primary human antigen-presenting cells and CatG may be of functional importance.
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Affiliation(s)
- Christina Stoeckle
- Hertie Institute for Clinical Brain Research, University of Tübingen, Germany
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2
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Lin YC, Chen CL, Nakano T, Goto S, Kao YH, Hsu LW, Lai CY, Jawan B, Cheng YF, Tateno C, Yoshizato K. Immunological role of indoleamine 2,3-dioxygenase in rat liver allograft rejection and tolerance. J Gastroenterol Hepatol 2008; 23:e243-50. [PMID: 17645734 DOI: 10.1111/j.1440-1746.2007.05036.x] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/09/2022]
Abstract
BACKGROUND AND AIM Indoleamine 2,3-dioxygenase (IDO) is expressed in the placenta and plays an essential role in maternal tolerance. Recent data showed that giving IDO inhibitor blocked liver allograft tolerance. However, the immunological role of IDO in rat liver allograft models has not been characterized. In the present study, the time-course of IDO expression and the localization of IDO were analyzed to address the role of IDO in the induction of tolerance. METHODS Rat orthotopic liver transplantations (OLT) were performed and IDO gene expression of OLT livers was analyzed. Immunohistochemistry was used to evaluate the localization of IDO-expressed cells in the liver. RESULTS The IDO gene was detected in the allogeneic liver graft at the acute phase but the signal could not be detected when these OLT rats were treated with cyclosporinee A. The time-course of IDO gene expression in liver grafts of the spontaneous tolerant OLT model revealed that the IDO mRNA was expressed in both the rejection phase and the induction phase of tolerance, but the signal was gradually lowered during the maintenance phase of tolerance. Immunohistochemistry confirmed that the IDO protein was detected in antigen-presenting cells but not in hepatocytes. CONCLUSION Our results demonstrated that IDO is induced in antigen-presenting cells of rat liver allografts under drug-free status, suggesting that indirect or direct recognition of donor antigen and further T-cell activation may be inhibited. IDO may act as a local immunosuppressive molecule to protect transplanted cells, tissues and organs from immune attack.
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MESH Headings
- Animals
- Antigen-Presenting Cells/enzymology
- Antigen-Presenting Cells/immunology
- Blotting, Western
- Cells, Cultured
- Cyclosporine/pharmacology
- Disease Models, Animal
- Gene Expression Regulation, Enzymologic
- Graft Rejection/enzymology
- Graft Rejection/genetics
- Graft Rejection/immunology
- Graft Rejection/prevention & control
- Immune Tolerance/drug effects
- Immunohistochemistry
- Immunosuppressive Agents/pharmacology
- Indoleamine-Pyrrole 2,3,-Dioxygenase/genetics
- Indoleamine-Pyrrole 2,3,-Dioxygenase/metabolism
- Liver/drug effects
- Liver/enzymology
- Liver/immunology
- Liver/surgery
- Liver Transplantation
- Male
- RNA, Messenger/metabolism
- Rats
- Rats, Inbred Lew
- T-Lymphocytes/immunology
- Time Factors
- Transplantation, Homologous
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Affiliation(s)
- Yu-Chun Lin
- Department of Biological Science, Developmental Biology Laboratory, Graduate School of Science, Hiroshima University, Hiroshima, Japan.
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3
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Abstract
A novel structure shows tissue transglutaminase in its catalytically active form, revealing the mode of action of this crosslinking enzyme and facilitating the development of specific inhibitors for use in various diseases in which transglutaminases are implicated.
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Affiliation(s)
- Frits Koning
- Department of Immunohematology and Blood Transfusion, Leiden University Medical Center, Leiden, The Netherlands.
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4
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Aizu K, Li W, Yajima T, Arai T, Shimoda K, Nimura Y, Yoshikai Y. An important role of Tyk2 in APC function of dendritic cells for priming CD8+ T cells producing IFN-gamma. Eur J Immunol 2007; 36:3060-70. [PMID: 17048270 DOI: 10.1002/eji.200636173] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
Tyrosine kinase 2 (Tyk2) contributes to the signals triggered by IL-12 for IFN-gamma production by NK cells and T cells. We found in this study that Tyk2-deficient (-/-) mice showed increased susceptibility at the early stage after an i.p. infection with Listeria monocytogenes, accompanied by impaired IFN-gamma production. The numbers of both MHC class Ib (H2-M3)- or MHC class Ia (Kb)-restricted CD8+ T cells producing IFN-gamma and exhibiting cytotoxicity were significantly decreased in Tyk2-/- mice after infection with L. monocytogenes. Using an adoptive transfer system of OT-I cells expressing OVA(257-264)/Kb-specific TCR into Tyk2-/- mice followed by challenge with recombinant L. monocytogenes expressing OVA, we found that the defective Tyk2 signaling in the host environment was at least partially responsible for the impaired CD8+ T cytotoxic-1 (Tc1) cell responses in Tyk2-/- mice following the infection. Adoptive transfer with MHC class Ib- or MHC class Ia-binding peptide-pulsed BM-derived DC from Tyk2-/- mice induced lower levels of the Ag-specific CD8+ Tc1 cells producing IFN-gamma. These results suggest that Tyk2 signaling is also important for DC function in the induction of MHC class Ia- and class Ib-restricted CD8+ Tc1 cells following L. monocytogenes infection.
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Affiliation(s)
- Keiji Aizu
- Division of Host Defense, Research Center of Prevention of Infectious Diseases, Medical Institute of Bioregulation, Kyushu University, Fukuoka, Japan
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5
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Brännström J, Hässler S, Peltonen L, Herrmann B, Winqvist O. Defect internalization and tyrosine kinase activation in Aire deficient antigen presenting cells exposed to Candida albicans antigens. Clin Immunol 2006; 121:265-73. [PMID: 16982213 DOI: 10.1016/j.clim.2006.08.005] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2006] [Revised: 07/10/2006] [Accepted: 08/08/2006] [Indexed: 01/12/2023]
Abstract
Patients with Autoimmune polyendocrine syndrome type I (APS I) present with multiple endocrine failures due to organ-specific autoimmune disease, thought to be T-cell-mediated. Paradoxically, APS I patients suffer from chronic mucocutaneous candidiasis. The mutated gene has been identified as the Autoimmune regulator (AIRE). Aire is expressed in medullary epithelial cells of the thymus and in antigen presenting cells in the periphery. T cells from Aire deficient mice and men displayed an enhanced proliferative response against Candida antigen in vitro, suggesting that Aire deficient T cells are competent in recognizing Candida albicans. In contrast, monocytes from APS I patients displayed a decreased and delayed internalization of zymosan. Furthermore, Candida antigen activated monocytes from APS I patients show decreased and altered phoshotyrosine kinase activation. In conclusion, Aire deficient APCs have a defect receptor mediated internalization of Candida which affects kinase activation, likely altering the innate Candida immune response.
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Affiliation(s)
- Johan Brännström
- Karolinska Institutet, Department of Medicine, Unit of Clinical Allergy Research L2:04, Karolinska Hospital, SE-171 76 Stockholm, Sweden
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6
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Labuda T, Christensen JP, Rasmussen S, Bonnesen B, Karin M, Thomsen AR, Odum N. MEK kinase 1 is a negative regulator of virus-specific CD8(+) T cells. Eur J Immunol 2006; 36:2076-84. [PMID: 16761309 DOI: 10.1002/eji.200535163] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
MEK kinase 1 (MEKK1) is a potent JNK-activating kinase, a regulator of T helper cell differentiation, cytokine production and proliferation in vitro. Using mice deficient for MEKK1 activity (Mekk1(DeltaKD)) exclusively in their hematopoietic system, we show that MEKK1 has a negative regulatory role in the generation of a virus-specific immune response. Mekk1(DeltaKD) mice challenged with vesicular stomatitis virus (VSV) showed a fourfold increase in splenic CD8(+) T cell numbers. In contrast, the number of splenic T cells in infected WT mice was only marginally increased. The CD8(+) T cell expansion in Mekk1(DeltaKD) mice following VSV infection is virus-specific and the frequency of virus-specific T cells is significantly higher (more than threefold) in Mekk1(DeltaKD) as compared to WT animals. Moreover, the hyper-expansion of T cells seen in Mekk1(DeltaKD) mice after VSV infection is a result of increased proliferation, since a significantly higher percentage of virus-specific Mekk1(DeltaKD) CD8(+) T cells incorporated BrdU as compared to virus-specific WT CD8(+) T cells. In contrast, similar levels of apoptosis were detected in Mekk1(DeltaKD) and WT T cells following VSV infection. These results strongly suggest that MEKK1 plays a negative regulatory role in the expansion of virus-specific CD8(+) T cells in vivo.
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Affiliation(s)
- Tord Labuda
- Department of Medical Microbiology and Immunology, University of Copenhagen, Copenhagen, Denmark.
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7
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Abstract
Induction of T cell responses following engagement of the Ag-specific TCR depends on TCR-initiated rearrangements of the cellular actin cytoskeleton and highly coordinated and tightly regulated interactions and of diverse intracellular signaling proteins. In this study, we show that filamin A (FLNa), an actin-binding and signal mediator scaffolding protein, is required for T cell activation. Following Ag stimulation, FLNa was recruited to the T cell-APC contact area, where it colocalized with protein kinase C-theta (PKCtheta). Depletion of FLNa by RNA interference did not affect TCR-induced early tyrosine phosphorylation or actin polymerization but, nevertheless, resulted in impaired IL-2 expression by human primary T cells and reduced activation of NF-kappaB, AP-1, and NFAT reporter genes in transfected T cells. TCR stimulation induced stable physical association of FLNa with PKCtheta. Furthermore, the TCR/CD28-induced membrane translocation of PKCtheta was inhibited in FLNa-depleted T cells. These results reveal novel role for FLNa in the TCR/CD28 signaling pathway leading to transcription factor activation and IL-2 production, and suggest that this role is mediated, in part, through the inducible interaction of FLNa with PKCtheta.
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Affiliation(s)
- Keitaro Hayashi
- Division of Cell Biology, La Jolla Institute for Allergy and Immunology, San Diego, CA 92121, USA
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8
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Abstract
Dendritic cells from patients with cancer are deficient in number and functional activity, leading to inadequate tumor immunosurveillance as a result of poor induction of T-cell antitumor responses. Loaded dendritic cell therapy is a vaccination strategy aimed at eliciting tumor antigen-specific, T-cell immune responses. Loaded dendritic cell therapy using prostatic acid phosphatase (APC8015; Provenge, Dendreon Corp., Seattle, WA) as an immunogen has shown a survival benefit in patients with metastatic hormone-refractory prostate cancer in a randomized phase III trial. This review will summarize the prostate cancer clinical trials using APC8015 and discuss the potential future role of APC8015 in prostate cancer treatment.
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Affiliation(s)
- Amy M Lin
- Department of Medicine, University of California, San Francisco, San Francisco, CA 94115, USA
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9
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Abstract
Whether specific proteases influence MHC class II antigen presentation is still not clearly defined. Cathepsin D, one of the most abundant lysosomal proteases, is thought to be dispensable for MHC class II antigen presentation, yet in vitro digestions of antigen substrates with endosomes/lysosomes from antigen-presenting cells sometimes reveal a dominant role for pepstatin-sensitive aspartyl proteases of which cathepsin D is the major representative. We tested whether the aspartyl protease substrate myoglobin requires cathepsin D activity for presentation to T cells. Surprisingly, in dendritic cells (DC) lacking cathepsin D, presentation of two different myoglobin T cell epitopes was enhanced rather than hindered. This paradox is resolved by the finding that pepstatin-sensitive myoglobin processing activity persists in lysosomes from cathepsin D-null DC and that this reduced activity, most likely due to cathepsin E, is closer to the optimum level required for myoglobin antigen presentation. Our results indicate redundancy among lysosomal aspartyl proteases and show that while processing activities can be productive for MHC class II T cell epitope generation at one level, they can become destructive above an optimal level.
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Affiliation(s)
- Catherine X Moss
- Division of Cell Biology & Immunology, Wellcome Trust Biocentre, University of Dundee, Dundee, UK
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10
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Maemura K, Yanagawa Y, Obata K, Dohi T, Egashira Y, Shibayama Y, Watanabe M. Antigen-presenting cells expressing glutamate decarboxylase 67 were identified as epithelial cells in glutamate decarboxylase 67-GFP knock-in mouse thymus. ACTA ACUST UNITED AC 2006; 67:198-206. [PMID: 16573556 DOI: 10.1111/j.1399-0039.2006.00548.x] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
Glutamate decarboxylase (GAD), which has two isoforms, GAD65, and GAD67, is responsible for synthesis of the major inhibitory neurotransmitter, gamma-aminobutyric acid. GAD is expressed predominantly in the central nervous system; recent reports suggest that GAD is also expressed in non-neuronal organs including the pancreas. In the pancreatic islets, GAD serves as one of the autoantigens in type I diabetes mellitus. Recent flow cytometric analyses have shown that a variety of self-antigens, including GAD, are ectopically transcribed and expressed in particular cell populations of the thymus, although consensus concerning the cellular phenotype has not been obtained. The aim of this study was to clarify the localization and cellular phenotype of GAD67-expressing cells in the thymus at a cellular level with a novel approach using GAD67-green fluorescent protein (GFP) knock-in mice, in which GFP is expressed specifically in GAD67-positive cells. GFP-positive cells were detected in the thymic medulla and were identified as epithelial cells by immunohistochemistry. Almost all GFP-positive cells were positive for major histocompatibility complex (MHC) class II antigen staining and were positive for both cytokeratin and Ulex Europaeus Agglutinin I, markers of medullary thymic epithelial cells, but were negative for CD11c, Gr-1, and CD45, markers of dendritic cells, macrophages, and B-lymphocytes, respectively.
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Affiliation(s)
- K Maemura
- Department of Anatomy, Osaka Medical College, Japan
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11
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Abstract
The endosomal pathway of antigen presentation leads to the display of peptides on major histocompatibility complex (MHC) class II molecules at the cell surface of antigen-presenting cells (APCs). The pathway involves two major steps, invariant chain degradation and antigen processing, which take place in the late endosomes/lysosomes. So far, of the known lysosomal proteases, only cathepsin L and cathepsin S have been shown to have a non-redundant role in endosomal presentation in vivo. Besides being engaged in the degradation of invariant chain, these enzymes also mediate the processing of antigens in distinct cell types. Surprisingly, these enzymes are active in different types of APCs, and this defined expression pattern seems to be enforced by regulatory mechanisms acting on multiple levels.
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Affiliation(s)
- Lianne C Hsing
- Department of Immunology, Howard Hughes Medical Institute, University of Washington School of Medicine, Seattle, WA 98195, USA
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12
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Abstract
Although the endpoint of the class II antigen-processing pathway is well characterized, the processing events that lead to the production of class II major histocompatibility complex (MHC)/peptide complexes are not. It is generally assumed that protease action on native antigen substrates leads to unfolding and capture of either long or short peptides. Whether specific protease activities are needed for presentation of particular T-cell epitopes is largely unknown. Here, we review our recent studies that aim to identify the processing enzymes that initiate processing of different antigens. We suggest a general strategy that can potentially identify preferred relationships between substrates and processing enzymes in vitro and suggest ways in which these relationships can be tested in vivo. We draw heavily on the example of asparaginyl endopeptidase, which is involved in both productive and destructive processing of different antigen substrates. Overall, while there is undoubtedly redundancy in class II MHC antigen processing, the contributions of individual enzymes can be clearly dissected.
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Affiliation(s)
- Colin Watts
- Division of Cell Biology and Immunology, School of Life Science, University of Dundee, Dundee, UK.
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13
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Ise W, Nakamura K, Shimizu N, Goto H, Fujimoto K, Kaminogawa S, Hachimura S. Orally tolerized T cells can form conjugates with APCs but are defective in immunological synapse formation. J Immunol 2005; 175:829-38. [PMID: 16002680 DOI: 10.4049/jimmunol.175.2.829] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
Oral tolerance is systemic immune hyporesponsiveness induced by the oral administration of soluble Ags. Hyporesponsiveness of Ag-specific CD4 T cells is responsible for this phenomenon. However, the molecular mechanisms underlying the hyporesponsive state of these T cells are not fully understood. In the present study, we investigated the ability of orally tolerized T cells to form conjugates with Ag-bearing APCs and to translocate TCR, protein kinase C-theta (PKC-theta), and lipid rafts into the interface between T cells and APCs. Orally tolerized T cells were prepared from the spleens of OVA-fed DO11.10 mice. Interestingly, the orally tolerized T cells did not show any impairment in the formation of conjugates with APCs. The conjugates were formed in a LFA-1-dependent manner. Upon antigenic stimulation, the tolerized T cells could indeed activate Rap1, which is critical for LFA-1 activation and thus cell adhesion. However, orally tolerized T cells showed defects in the translocation of TCR, PKC-theta, and lipid rafts into the interface between T cells and APCs. Translocation of TCR and PKC-theta to lipid raft fractions upon antigenic stimulation was also impaired in the tolerized T cells. Ag-induced activation of Vav, Rac1, and cdc42, which are essential for immunological synapse and raft aggregation, were down-regulated in orally tolerized T cells. These results demonstrate that orally tolerized T cells can respond to specific Ags in terms of conjugate formation but not with appropriate immunological synapse formation. This may account for the hyporesponsive state of orally tolerized T cells.
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Affiliation(s)
- Wataru Ise
- Department of Applied Biological Chemistry, University of Tokyo, Bunkyo-ku, Tokyo 113-8657, Japan
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14
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Maehr R, Hang HC, Mintern JD, Kim YM, Cuvillier A, Nishimura M, Yamada K, Shirahama-Noda K, Hara-Nishimura I, Ploegh HL. Asparagine Endopeptidase Is Not Essential for Class II MHC Antigen Presentation but Is Required for Processing of Cathepsin L in Mice. J Immunol 2005; 174:7066-74. [PMID: 15905550 DOI: 10.4049/jimmunol.174.11.7066] [Citation(s) in RCA: 84] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Class II MHC molecules survey the endocytic compartments of APCs and present antigenic peptides to CD4 T cells. In this context, lysosomal proteases are essential not only for the generation of antigenic peptides but also for proteolysis of the invariant chain to allow the maturation of class II MHC molecules. Recent studies with protease inhibitors have implicated the asparagine endopeptidase (AEP) in class II MHC-restricted Ag presentation. We now report that AEP-deficient mice show no differences in processing of the invariant chain or maturation of class II MHC products compared with wild-type mice. In the absence of AEP, presentation to primary T cells of OVA and myelin oligodendrocyte glycoprotein, two Ags that contain asparagine residues within or in proximity to the relevant epitopes was unimpaired. Cathepsin (Cat) L, a lysosomal cysteine protease essential for the development to CD4 and NK T cells, fails to be processed into its mature two-chain form in AEP-deficient cells. Despite this, the numbers of CD4 and NK T cells are normal, showing that the single-chain form of Cat L is sufficient for its function in vivo. We conclude that AEP is essential for processing of Cat L but not for class II MHC-restricted Ag presentation.
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MESH Headings
- Animals
- Antigen Presentation/genetics
- Antigen Presentation/immunology
- Antigen-Presenting Cells/enzymology
- Antigen-Presenting Cells/immunology
- Antigen-Presenting Cells/metabolism
- Antigens, Differentiation, B-Lymphocyte/immunology
- Antigens, Differentiation, B-Lymphocyte/metabolism
- CD4-Positive T-Lymphocytes/cytology
- CD4-Positive T-Lymphocytes/enzymology
- Cathepsin L
- Cathepsins/deficiency
- Cathepsins/genetics
- Cathepsins/metabolism
- Cell Differentiation/genetics
- Cell Differentiation/immunology
- Cysteine Endopeptidases/deficiency
- Cysteine Endopeptidases/genetics
- Cysteine Endopeptidases/metabolism
- Cysteine Endopeptidases/physiology
- Histocompatibility Antigens Class II/genetics
- Histocompatibility Antigens Class II/immunology
- Histocompatibility Antigens Class II/metabolism
- Isoenzymes/deficiency
- Isoenzymes/metabolism
- Killer Cells, Natural/cytology
- Killer Cells, Natural/enzymology
- Mice
- Mice, Inbred C57BL
- Mice, Knockout
- Mice, Transgenic
- Myelin Proteins
- Myelin-Associated Glycoprotein/immunology
- Myelin-Associated Glycoprotein/metabolism
- Myelin-Oligodendrocyte Glycoprotein
- Ovalbumin/immunology
- Ovalbumin/metabolism
- Protein Processing, Post-Translational/genetics
- Protein Processing, Post-Translational/immunology
- T-Lymphocyte Subsets/cytology
- T-Lymphocyte Subsets/enzymology
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Affiliation(s)
- René Maehr
- Department of Pathology, Harvard Medical School, Boston, MA 02115, USA
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15
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Canadien V, Tan T, Zilber R, Szeto J, Perrin AJ, Brumell JH. Cutting edge: microbial products elicit formation of dendritic cell aggresome-like induced structures in macrophages. J Immunol 2005; 174:2471-5. [PMID: 15728449 DOI: 10.4049/jimmunol.174.5.2471] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
In response to a maturation stimulus, dendritic cells undergo the formation of ubiquitinated protein aggregates known as dendritic cell aggresome-like induced structures (DALIS). DALIS are thought to act as Ag storage structures, allowing for the prioritized degradation of proteins during infection. In this study, we demonstrate that murine macrophages can also form ubiquitinated protein aggregates that are indistinguishable from DALIS. These were formed in a dose- and time-dependent manner, and in response to a variety of microbial products. Surprisingly, the proteasome did not accumulate on these ubiquitinated protein structures, further underlining the difference between DALIS and aggresomes. Our studies suggest that DALIS formation is important for the function of Ag-presenting immune cells during infection.
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Affiliation(s)
- Veronica Canadien
- Infection, Immunity, Injury, and Repair Program, Hospital for Sick Children, University of Toronto, Toronto, Ontario, Canada
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16
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Cong Y, Konrad A, Iqbal N, Hatton RD, Weaver CT, Elson CO. Generation of antigen-specific, Foxp3-expressing CD4+ regulatory T cells by inhibition of APC proteosome function. J Immunol 2005; 174:2787-95. [PMID: 15728488 DOI: 10.4049/jimmunol.174.5.2787] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
We tested the hypothesis that immature APC, whose NF-kappaB-signaling pathway and thus maturation was blocked by the proteosome inhibitor benzyloxycarbonyl-isoleucyl-glutamyl(O-tert-butyl)-alanyl-leucinal (PSI), could be a source of Ag-specific regulatory T (Treg) cells. DO11.10 CD4(+) T cells that were incubated with Ag- and PSI-pulsed APC proliferated poorly, produced less IL-2, IFN-gamma, and IL-10 in secondary cultures, and inhibited the response of both naive and memory CD4(+) T cells stimulated by Ag-pulsed APC. The generation of PSI-APC Treg cells required IL-10 production by APC. PSI-APC Treg cell inhibition required cell-cell contact but not IL-10 or TGF-beta. Addition of IL-2 did not reverse, but Ab to CTLA-4 did reverse partially the inhibitory effect. Depletion of CD25(+) T cells before initial culture with PSI-APC did not affect Treg generation. PSI-APC Treg cells expressed high levels of Foxp3, inhibited proliferation of naive DO11.10 T cells in vivo, and abrogated colitis driven by a memory Th1 response to bacterial-associated Ag. We conclude that NF-kappaB-blocked, immature APC are able to induce the differentiation of Treg cells that can function in vitro and in vivo in an Ag-specific manner.
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Affiliation(s)
- Yingzi Cong
- Division of Gastroenterology and Hepatology, Department of Medicine, University of Alabama, Birmingham, AL 35294, USA
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17
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Abstract
Antigen-presenting cells (APCs) internalize antigens and present antigen-derived peptides to T cells. Although APCs have been thought to exhibit a well-developed capacity for lysosomal proteolysis, here we found that they can exhibit two distinct strategies upon antigen encounter. Whereas macrophages contained high levels of lysosomal proteases and rapidly degraded internalized proteins, dendritic cells (DCs) and B lymphocytes were protease-poor, resulting in a limited capacity for lysosomal degradation. Consistent with these findings, DCs in vivo degraded internalized antigens slowly and thus retained antigen in lymphoid organs for extended periods. Limited lysosomal proteolysis also favored antigen presentation. These results help explain why DCs are able to efficiently accumulate, process, and disseminate antigens and microbes systemically for purposes of tolerance and immunity.
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Affiliation(s)
- Lélia Delamarre
- Department of Cell Biology and Department of Immunobiology, Ludwig Institute for Cancer Research, Yale University School of Medicine, 333 Cedar Street, Post Office Box 208002, New Haven, CT 06520-8002, USA
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18
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Neijssen J, Herberts C, Drijfhout JW, Reits E, Janssen L, Neefjes J. Cross-presentation by intercellular peptide transfer through gap junctions. Nature 2005; 434:83-8. [PMID: 15744304 DOI: 10.1038/nature03290] [Citation(s) in RCA: 343] [Impact Index Per Article: 18.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2004] [Accepted: 12/14/2004] [Indexed: 11/09/2022]
Abstract
Major histocompatibility complex (MHC) class I molecules present peptides that are derived from endogenous proteins. These antigens can also be transferred to professional antigen-presenting cells in a process called cross-presentation, which precedes initiation of a proper T-cell response; but exactly how they do this is unclear. We tested whether peptides can be transferred directly from the cytoplasm of one cell into the cytoplasm of its neighbour through gap junctions. Here we show that peptides with a relative molecular mass of up to approximately 1,800 diffuse intercellularly through gap junctions unless a three-dimensional structure is imposed. This intercellular peptide transfer causes cytotoxic T-cell recognition of adjacent, innocent bystander cells as well as activated monocytes. Gap-junction-mediated peptide transfer is restricted to a few coupling cells owing to the high cytosolic peptidase activity. We present a mechanism of antigen acquisition for cross-presentation that couples the antigen presentation system of two adjacent cells and is lost in most tumours: gap-junction-mediated intercellular peptide coupling for presentation by bystander MHC class I molecules and transfer to professional antigen presenting cells for cross-priming.
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Affiliation(s)
- Joost Neijssen
- Division of Tumor Biology, The Netherlands Cancer Institute, Plesmanlaan 121, 1066 CX Amsterdam, The Netherlands.
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19
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Abstract
Chlamydia trachomatis is a global human pathogen causing diseases ranging from blinding trachoma to pelvic inflammatory disease. To explore how innate and adaptive immune responses cooperate to protect against systemic infection with C. trachomatis L2, we investigated the role of macrophages (Mphi) and dendritic cells (DCs) in the stimulation of C. trachomatis-specific CD8(+) T cells. We found that C. trachomatis infection of Mphi and DCs is far less productive than infection of nonprofessional APCs, the typical targets of infection. However, despite the limited replication of C. trachomatis within Mphi and DCs, infected Mphi and DCs process and present C. trachomatis CD8(+) T cell Ag in a proteasome-dependent manner. These findings suggest that although C. trachomatis is a vacuolar pathogen, some Ags expressed in infected Mphi and DCs are processed in the host cell cytosol for presentation to CD8(+) T cells. We also show that even though C. trachomatis replicates efficiently within nonprofessional APCs both in vitro and in vivo, Ag presentation by hematopoietic cells is essential for initial stimulation of C. trachomatis-specific CD8(+) T cells. However, when DCs infected with C. trachomatis ex vivo were adoptively transferred into naive mice, they failed to prime C. trachomatis-specific CD8(+) T cells. We propose a model for priming C. trachomatis-specific CD8(+) T cells whereby DCs acquire C. trachomatis Ag by engulfing productively infected nonprofessional APCs and then present the Ag to T cells via a mechanism of cross-presentation.
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Affiliation(s)
- Lisa N Steele
- Department of Microbiology and Molecular Genetics, Harvard Medical School, 200 Longwood Avenue, Boston, MA 02115, USA
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20
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Salerno-Gonçalves R, Fernandez-Viña M, Lewinsohn DM, Sztein MB. Identification of a human HLA-E-restricted CD8+ T cell subset in volunteers immunized with Salmonella enterica serovar Typhi strain Ty21a typhoid vaccine. J Immunol 2004; 173:5852-62. [PMID: 15494539 DOI: 10.4049/jimmunol.173.9.5852] [Citation(s) in RCA: 130] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Our previous studies in volunteers immunized with Salmonella enterica serovar Typhi (S. Typhi) have suggested an important role for CD8+ T cells in host defense. In this study we describe a novel subset of nonclassical human HLA-E-restricted S. Typhi-specific CD8+ T cells derived from PBMC of Ty21a typhoid vaccinees. CD3+CD8+CD4-CD56- T cells effectively killed S. Typhi-infected targets regardless of whether they share classical HLA class I molecules with them, by a FAS-independent, granule-dependent mechanism, as evidenced by induction of granzyme B release and the blocking effects of concanamycin and strontium ions. The expression of HLA-E Ags, but not CD1-a, -b, or -c, on the membrane of S. Typhi-infected targets rendered them susceptible to lysis. Moreover, anti-HLA-E Abs partially blocked these responses. We also demonstrated that presentation of S. Typhi Ags via HLA-E could stimulate IFN-gamma production. Increases in the net frequency of IFN-gamma spot-forming cells were observed in the presence of targets coated with peptides that contain S. Typhi GroEL HLA-E binding motifs. These results demonstrate that HLA-E binds nonamer peptides derived from bacterial proteins and trigger CD8+-mediated lysis and IFN-gamma production when exposed to infected targets, raising the possibility that this novel effector mechanism might contribute to host defense against intracellular bacterial infections.
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MESH Headings
- Adult
- Antibodies, Blocking/metabolism
- Antibodies, Monoclonal/metabolism
- Antigen Presentation/immunology
- Antigen-Presenting Cells/enzymology
- Antigen-Presenting Cells/immunology
- Antigens, Bacterial/immunology
- Antigens, Bacterial/metabolism
- Binding Sites, Antibody
- CD3 Complex/biosynthesis
- CD56 Antigen/biosynthesis
- CD8-Positive T-Lymphocytes/immunology
- CD8-Positive T-Lymphocytes/microbiology
- Cell Line
- Cell Line, Transformed
- Cytoplasmic Granules/enzymology
- Cytoplasmic Granules/immunology
- Cytoplasmic Granules/microbiology
- Cytotoxicity Tests, Immunologic/methods
- HLA Antigens/immunology
- HLA Antigens/metabolism
- Histocompatibility Antigens Class I/immunology
- Histocompatibility Antigens Class I/metabolism
- Humans
- Lymphocyte Count
- Middle Aged
- Peptide Fragments/immunology
- Peptide Fragments/metabolism
- Proteasome Endopeptidase Complex/metabolism
- Protein Binding/immunology
- Protein Processing, Post-Translational/immunology
- Salmonella typhi/immunology
- T-Lymphocytes, Cytotoxic/immunology
- T-Lymphocytes, Cytotoxic/microbiology
- Typhoid-Paratyphoid Vaccines/administration & dosage
- Typhoid-Paratyphoid Vaccines/immunology
- HLA-E Antigens
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21
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Lu J, Higashimoto Y, Appella E, Celis E. Multiepitope Trojan antigen peptide vaccines for the induction of antitumor CTL and Th immune responses. J Immunol 2004; 172:4575-82. [PMID: 15034075 DOI: 10.4049/jimmunol.172.7.4575] [Citation(s) in RCA: 55] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
We describe in this study a strategy to produce synthetic vaccines based on a single polypeptide capable of eliciting strong immune responses to a combination CTL and Th epitopes with the purpose of treating malignancies or preventing infectious diseases. This strategy is based on the capacity of Trojan Ags to deliver exogenous Ags into the intracellular compartments, where processing into MHC-binding peptides takes place. Our previous work demonstrated that Trojan Ags containing a CTL epitope localized to intracellular compartments, where MHC class I-binding peptides were generated in a TAP-independent fashion by the action of various exopeptidases and the endopeptidase furin. In this study, we report that Trojan Ags containing several CTL epitopes joined via furin-sensitive linkers generated all of the corresponding MHC class I-binding peptides, which were recognized by CTL. However, Trojan Ags prepared with furin-resistant linkers failed to produce the MHC class I-binding peptides. We also present data indicating that Trojan Ags bearing both CTL and Th epitopes can generate the corresponding MHC class I- and II-binding peptides, which are capable of stimulating T cell responses. Most significantly, in vivo vaccination of mice with a single injection of multiepitope Trojan Ags resulted in strong CTL and Th responses that translated into significant antitumor responses in a model of malignant melanoma. The overall results indicate that Trojan Ags prepared with furin-sensitive linkers are ideal candidates for producing synthetic multiepitope vaccines for the induction of CTL and Th responses that could be used against a variety of diseases, including cancer.
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MESH Headings
- Animals
- Antigen Presentation
- Antigen-Presenting Cells/enzymology
- Antigen-Presenting Cells/immunology
- Antigen-Presenting Cells/metabolism
- Cancer Vaccines/administration & dosage
- Cancer Vaccines/immunology
- Cell Line, Tumor
- Cytotoxicity, Immunologic/immunology
- Egg Proteins/immunology
- Epitopes, T-Lymphocyte/administration & dosage
- Epitopes, T-Lymphocyte/immunology
- Female
- Furin/pharmacology
- Injections, Subcutaneous
- Mastocytoma/immunology
- Mastocytoma/prevention & control
- Melanoma, Experimental/immunology
- Melanoma, Experimental/prevention & control
- Mice
- Mice, Inbred C57BL
- Mice, Transgenic
- Neoplasm Transplantation
- Ovalbumin/immunology
- Peptide Fragments/immunology
- T-Lymphocytes, Cytotoxic/immunology
- T-Lymphocytes, Cytotoxic/metabolism
- T-Lymphocytes, Helper-Inducer/immunology
- Transfection
- Vaccines, Subunit/administration & dosage
- Vaccines, Subunit/immunology
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Affiliation(s)
- Jun Lu
- Department of Immunology and Cancer Center, Mayo College of Medicine, Mayo Clinic, Rochester, MN 55905, USA
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22
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Garçon F, Bismuth G, Isnardon D, Olive D, Nunès JA. Tec Kinase Migrates to the T Cell-APC Interface Independently of Its Pleckstrin Homology Domain. J Immunol 2004; 173:770-5. [PMID: 15240663 DOI: 10.4049/jimmunol.173.2.770] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Tec is the prototypical member of the Tec tyrosine kinases family, which plays an important role in T cell signaling. We show in this study that Tec translocates to the immunological synapse when a T cell contacts a dendritic cell. Surprisingly, the presence of the pleckstrin homology (PH) domain of Tec is not required for this accumulation, and despite a strong activation of 3'-phosphorylated phosphoinositide lipids synthesis during the synapse formation, the Tec PH domain is not redistributed to the T cell plasma membrane. In contrast, we demonstrate that an active Src homology 3 domain is absolutely required, underlining the essential role played by this part of the molecule in the recruitment and/or stabilization of Tec at the immunological synapse. Our results nevertheless suggest that the PH domain controls the kinase activity of the molecule in vivo. We finally demonstrate that the two domains are necessary to trigger transcriptional events following Ag presentation. These data support a model in which the plasma membrane recruitment of the PH-containing protein Tec is not dependent on the production of 3'-phosphorylated phosphoinositide lipids by the PI3K, but rather on an intact Src homology 3 domain.
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Affiliation(s)
- Fabien Garçon
- Institut National de la Santé et de la Recherche Médicale Unité Mixte de Recherche 599, Université de la Méditerranée, Marseille, France
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23
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Morrison AC, Wilson CB, Ray M, Correll PH. Macrophage-stimulating protein, the ligand for the stem cell-derived tyrosine kinase/RON receptor tyrosine kinase, inhibits IL-12 production by primary peritoneal macrophages stimulated with IFN-gamma and lipopolysaccharide. J Immunol 2004; 172:1825-32. [PMID: 14734766 DOI: 10.4049/jimmunol.172.3.1825] [Citation(s) in RCA: 63] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
IL-12, produced by APCs during the initial stages of an immune response, plays a pivotal role in the induction of IFN-gamma by NK and gammadeltaT cells and in driving the differentiation of Th1 cells, thus providing a critical link between innate and acquired immunity. Due to the unique position occupied by IL-12 in the regulation of immunity, many mechanisms have evolved to modulate IL-12 production. We have shown previously that macrophage-stimulating protein (MSP), the ligand for the stem cell-derived tyrosine kinase/recepteur d'origine nantais (RON) receptor, inhibits NO production by macrophages in response to IFN-gamma and enhances the expression of arginase. Mice lacking RON exhibit increased inflammation in a delayed-type hypersensitivity reaction and increased susceptibility to endotoxic shock. In this study we demonstrate that pretreatment of macrophages with MSP before IFN-gamma and LPS results in the complete inhibition of IL-12 production due to suppression of p40 expression. This response is mediated by the RON receptor, and splenocytes from RON(-/-) animals produce increased levels of IFN-gamma. MSP pretreatment of macrophages resulted in decreased tyrosine phosphorylation of Stat-1 and decreased expression of IFN consensus sequence binding protein in response to inflammatory cytokines. In addition to IL-12, the expression of IL-15 and IL-18, cytokines that are also dependent on IFN consensus sequence binding protein activation, is inhibited by pretreatment with MSP before IFN-gamma and LPS. We also show that the ability of MSP to inhibit IL-12 production is independent of IL-10. Taken together, these results suggest that MSP may actively suppress cell-mediated immune responses through its ability to down-regulate IL-12 production and thus inhibit classical activation of macrophages.
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Affiliation(s)
- Amy C Morrison
- Department of Veterinary Science, Graduate Program in Biochemistry, Microbiology, and Molecular Biology, Pennsylvania State University, University Park, PA 16802, USA
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24
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Burster T, Beck A, Tolosa E, Marin-Esteban V, Rötzschke O, Falk K, Lautwein A, Reich M, Brandenburg J, Schwarz G, Wiendl H, Melms A, Lehmann R, Stevanovic S, Kalbacher H, Driessen C. Cathepsin G, and Not the Asparagine-Specific Endoprotease, Controls the Processing of Myelin Basic Protein in Lysosomes from Human B Lymphocytes. J Immunol 2004; 172:5495-503. [PMID: 15100291 DOI: 10.4049/jimmunol.172.9.5495] [Citation(s) in RCA: 62] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
The asparagine-specific endoprotease (AEP) controls lysosomal processing of the potential autoantigen myelin basic protein (MBP) by human B lymphoblastoid cells, a feature implicated in the immunopathogenesis of multiple sclerosis. In this study, we demonstrate that freshly isolated human B lymphocytes lack significant AEP activity and that cleavage by AEP is dispensable for proteolytic processing of MBP in this type of cell. Instead, cathepsin (Cat) G, a serine protease that is not endogenously synthesized by B lymphocytes, is internalized from the plasma membrane and present in lysosomes from human B cells where it represents a major functional constituent of the proteolytic machinery. CatG initialized and dominated the destruction of intact MBP by B cell-derived lysosomal extracts, degrading the immunodominant MBP epitope and eliminating both its binding to MHC class II and a MBP-specific T cell response. Degradation of intact MBP by CatG was not restricted to a lysosomal environment, but was also performed by soluble CatG. Thus, the abundant protease CatG might participate in eliminating the immunodominant determinant of MBP. Internalization of exogenous CatG represents a novel mechanism of professional APC to acquire functionally dominant proteolytic activity that complements the panel of endogenous lysosomal enzymes.
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Affiliation(s)
- Timo Burster
- Department of Medicine II, University of Tübingen, Tübingen, Germany
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25
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Abstract
MHC-class-I-presented peptides are predominantly generated by the proteasome system. IFN-gamma strongly influences the processing efficiency by inducing immunoproteasome formation and proteasome activator PA28 synthesis. Depending on the protein substrate, the presence of immunoproteasomes and PA28 influence epitope liberation either positively or negatively. Abundantly occurring defective ribosomal products are a major source for proteasome-dependent antigen processing; however, antigen presentation is relatively inefficient. This is in part due to the existence of a panel of cytosolic aminopeptidases, such as bleomycin hydrolase (BH), puromycin-sensitive aminopeptidase (PSA) and thimet oligoendopeptidase (TOP), that can destroy epitopes or their precursors. Other aminopeptidases, such as leucine aminopeptidase (LAP) and endoplasmic reticulum aminopeptidase 1 (ERAP 1), can trim epitope precursors from the amino terminus to their correct size for MHC class I binding to enhance antigen presentation. Recent evidence suggests that tripeptidyl peptidase II (TPPII), a large peptidase with exo-and endo-proteolytic activities, is also involved in antigen processing and may generate a specific set of MHC class I epitopes.
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Affiliation(s)
- Peter Michael Kloetzel
- Institut für Biochemie, Charité-Medizinische Fakultät der Humboldt Universität zu Berlin, Monbijoustrasse 2, 10117 Berlin, Germany.
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26
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Suzuki N, Suzuki S, Eriksson U, Hara H, Mirtosis C, Chen NJ, Wada T, Bouchard D, Hwang I, Takeda K, Fujita T, Der S, Penninger JM, Akira S, Saito T, Yeh WC. IL-1R-Associated Kinase 4 Is Required for Lipopolysaccharide- Induced Activation of APC. J Immunol 2003; 171:6065-71. [PMID: 14634120 DOI: 10.4049/jimmunol.171.11.6065] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
The bacterial product LPS is a critical stimulus for the host immune system in the response against the corresponding bacterial infection. LPS provides an activation stimulus for macrophages and a maturation signal for dendritic cells to set up innate and adaptive immune responses, respectively. The signaling cascade of myeloid differentiation factor 88-->IL-1R-associated kinase (IRAK)-->TNFR-associated factor 6 has been implicated in mediating LPS signaling. In this report, we studied the function of IRAK-4 in various LPS-induced signals. We found that IRAK-4-deficient cells were severely impaired in producing some IFN-regulated genes as well as inflammatory cytokines in response to LPS. Among the critical downstream signaling pathways induced by LPS, NF-kappaB activation but not IFN regulatory factor 3 or STAT1 activation was defective in cells lacking IRAK-4. IRAK-4 was also required for the proper maturation of dendritic cells by LPS stimulation, particularly in terms of cytokine production and the ability to stimulate Th cell differentiation. Our results demonstrate that IRAK-4 is critical for the LPS-induced activations of APCs.
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Affiliation(s)
- Nobutaka Suzuki
- Advanced Medical Discovery Institute, University Health Network and Department of Medical Biophysics, University of Toronto, Toronto, Ontario, Canada
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27
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Affiliation(s)
- Andrew L Mellor
- Department of Medicine, Medical College of Georgia, Augusta GA 30912, USA
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28
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29
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Sinnathamby G, Eisenlohr LC. Presentation by recycling MHC class II molecules of an influenza hemagglutinin-derived epitope that is revealed in the early endosome by acidification. J Immunol 2003; 170:3504-13. [PMID: 12646611 DOI: 10.4049/jimmunol.170.7.3504] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
We investigated the roles of nascent and recycling MHC class II molecules (MHC II) in the presentation of two well-defined I-E(d)-restricted epitopes that are within distinct regions of the influenza virus hemagglutinin (HA) protein. The site 3 epitope (S3; residues 302-313) lies in the stalk region that unfolds in response to mild acidification, while the site 1 epitope (S1; residues 107-119) is situated in the stable globular domain. In a murine B lymphoma cell line and an I-E(d)-transfected fibroblast cell line, presentation from inactivated virus of S3 is inhibited by primaquine, a compound that prevents recycling of cell surface proteins, including MHC II, while S1 presentation is unaffected. In contrast, brefeldin A, an agent that inhibits exit of proteins from the endoplasmic reticulum, selectively inhibited S1 presentation without affecting S3 presentation, suggesting that S1 presentation requires nascent MHC II. The use of agents that perturb endosomal function revealed a requirement for acidification of internalized viral particles for presentation of both epitopes. Notably, all compounds tested had similar effects on presentation of the two epitopes derived from endogenously synthesized HA. Thus, recycling I-E(d) molecules appear to be crucial for capturing and presenting an epitope that is revealed in mild acidic conditions following the uptake of virions or the synthesis of Ag, while nascent I-E(d) molecules are required for presentation of a second epitope located in a structurally constrained region of the same polypeptide. Viral glycoproteins, such as HA, may have been a major impetus for the evolutionary establishment of this recycling pathway.
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Affiliation(s)
- Gomathinayagam Sinnathamby
- Department of Microbiology and Immunology, Kimmel Cancer Institute, Thomas Jefferson University, Philadelphia, PA 19107-5541, USA
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30
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Ascherman DP, Oriss TB, Oddis CV, Wright TM. Critical requirement for professional APCs in eliciting T cell responses to novel fragments of histidyl-tRNA synthetase (Jo-1) in Jo-1 antibody-positive polymyositis. J Immunol 2002; 169:7127-34. [PMID: 12471150 DOI: 10.4049/jimmunol.169.12.7127] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Polymyositis (PM) is an autoimmune muscle disease characterized by oligoclonal T cell infiltrates mediating myocytotoxicity. Although antigenic triggers for this process remain undefined, clinically homogeneous subsets of PM patients are characterized by autoantibodies directed against nuclear and cytoplasmic Ags that include histidyl-tRNA synthetase (Jo-1). Available evidence suggests that formation of anti-Jo-1 autoantibodies is Ag-driven and therefore dependent on CD4(+) T cells that may also direct cytolytic CD8(+) T cells involved in myocyte destruction. To assess peripheral blood T cell responses to Jo-1, we first subcloned full-length human Jo-1 as well as novel fragments of Jo-1 into the maltose-binding protein expression vector pMALc2. Expressed proteins were then used in standard proliferation assays with either PBMC or autologous DCs as sources of APCs. Although PBMC-derived APCs and DCs both supported peripheral blood T cell proliferation when primed with full-length human Jo-1, only DCs promoted proliferative responses to a unique amino-terminal fragment of Jo-1. mAb blockade of different HLA Ags revealed that these responses were MHC class II dependent. Therefore, for the first time, these studies demonstrate anti-Jo-1 T cell responses in Jo-1 Ab-positive PM patients as well as in healthy control subjects. More importantly, this work underscores the critical importance of APC type in dictating T cell responses to a novel antigenic fragment of Jo-1.
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Affiliation(s)
- Dana P Ascherman
- Division of Rheumatology and Clinical Immunology, University of Pittsburgh School of Medicine, Pittsburgh, PA 15261, USA.
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31
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Bausinger H, Lipsker D, Ziylan U, Manié S, Briand JP, Cazenave JP, Muller S, Haeuw JF, Ravanat C, de la Salle H, Hanau D. Endotoxin-free heat-shock protein 70 fails to induce APC activation. Eur J Immunol 2002; 32:3708-13. [PMID: 12516564 DOI: 10.1002/1521-4141(200212)32:12<3708::aid-immu3708>3.0.co;2-c] [Citation(s) in RCA: 196] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Previous work has suggested that the peptide-carrier, heat-shock protein (hsp)70, could directly activate APC. Here we show that this ability is related to endotoxin contamination of the human rhsp70 produced in Escherichia coli. Hence, the ability of 1-3 microg/ml of rhsp70 to induce the maturation of human monocyte-derived DC is abrogated in the presence of the LPS-antagonist polymyxin B or when the rhsp70 contains less than 60 IU/mg endotoxin. Such a level of contamination of the rhsp70 is, however, sufficient - in the presence of soluble rCD14, the LPS co-receptor - to induce cytokine secretion from monocytes and DC, despite the presence of polymyxin B. However, when endotoxin contamination is below 10 IU/mg, rhsp70 does not induce cytokine secretion - even in the presence of soluble rCD14 - or activate p38 mitogen-activated protein kinase signaling pathways, thus showing that an "endotoxin free" hsp70 does not activate APC.
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Affiliation(s)
- Huguette Bausinger
- 1INSERM, Equipe Propre 99-08, Etablissement Français du Sang-Alsace, Strasbourg, France
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32
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Abstract
The mammalian legumain, also called asparaginyl endopeptidase (AEP), is critically involved in the processing of bacterial antigens for MHC class II presentation. In order to investigate the substrate specificity of AEP in the P1' position, we created a peptide library and digested it with purified pig kidney AEP. Digestion was less efficient only when proline was in the P1' position. Maximum AEP activity was found in lysosomal fractions of different types of antigen presenting cells (APC). When the multiple sclerosis-associated autoantigen myelin basic protein (MBP) was digested with AEP, the immunodominant epitope 83-99 was destroyed. Myoglobin as an alternative substrate was AEP resistant. These results suggest an important, but not necessarily critical role for AEP in lysosomal antigen degradation.
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Affiliation(s)
- Gerold Schwarz
- Institute of Physiological Chemistry, University of Tübingen, Ob dem Himmelreich 7, D-72074 Tübingen, Germany
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33
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Munn DH, Sharma MD, Lee JR, Jhaver KG, Johnson TS, Keskin DB, Marshall B, Chandler P, Antonia SJ, Burgess R, Slingluff CL, Mellor AL. Potential regulatory function of human dendritic cells expressing indoleamine 2,3-dioxygenase. Science 2002; 297:1867-70. [PMID: 12228717 DOI: 10.1126/science.1073514] [Citation(s) in RCA: 736] [Impact Index Per Article: 33.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
Antigen-presenting cells (APCs) can induce tolerance or immunity. We describe a subset of human APCs that express indoleamine 2,3-dioxygenase (IDO) and inhibit T cell proliferation in vitro. IDO-positive APCs constituted a discrete subset identified by coexpression of the cell-surface markers CD123 and CCR6. In the dendritic cell (DC) lineage, IDO-mediated suppressor activity was present in fully mature as well as immature CD123+ DCs. IDO+ DCs could also be readily detected in vivo, which suggests that these cells may represent a regulatory subset of APCs in humans.
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Affiliation(s)
- David H Munn
- Institute of Molecular Medicine and Genetics, Medical College of Georgia, Augusta, GA 30912, USA.
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34
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Aandahl EM, Moretto WJ, Haslett PA, Vang T, Bryn T, Tasken K, Nixon DF. Inhibition of antigen-specific T cell proliferation and cytokine production by protein kinase A type I. J Immunol 2002; 169:802-8. [PMID: 12097383 DOI: 10.4049/jimmunol.169.2.802] [Citation(s) in RCA: 72] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
cAMP inhibits biochemical events leading to T cell activation by triggering of an inhibitory protein kinase A (PKA)-C-terminal Src kinase pathway assembled in lipid rafts. In this study, we demonstrate that activation of PKA type I by Sp-8-bromo-cAMPS (a cAMP agonist) has profound inhibitory effects on Ag-specific immune responses in peripheral effector T cells. Activation of PKA type I inhibits both cytokine production and proliferative responses in both CD4(+) and CD8(+) T cells in a concentration-dependent manner. The observed effects of cAMP appeared to occur endogenously in T cells and were not dependent on APC. The inhibition of responses was not due to apoptosis of specific T cells and was reversible by a PKA type I-selective cAMP antagonist. This supports the notion of PKA type I as a key enzyme in the negative regulation of immune responses and a potential target for inhibiting autoreactive T cells.
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Affiliation(s)
- Einar Martin Aandahl
- Gladstone Institute of Virology and Immunology, University of California, San Francisco, CA 94141, USA.
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35
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Sancho D, Montoya MC, Monjas A, Gordón-Alonso M, Katagiri T, Gil D, Tejedor R, Alarcón B, Sánchez-Madrid F. TCR engagement induces proline-rich tyrosine kinase-2 (Pyk2) translocation to the T cell-APC interface independently of Pyk2 activity and in an immunoreceptor tyrosine-based activation motif-mediated fashion. J Immunol 2002; 169:292-300. [PMID: 12077257 DOI: 10.4049/jimmunol.169.1.292] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
The relocation of kinases in T lymphocytes during their cognate interaction with APCs is essential for lymphocyte activation. We found that the proline-rich tyrosine kinase-2 (Pyk2) is rapidly translocated to the T cell-APC contact area upon T cell-specific recognition of superantigen-pulsed APCs. Stimulation with anti-CD3-coated latex microspheres was sufficient for Pyk2 reorientation, and the coengagement of CD28 boosted Pyk2 redistribution. Nevertheless, Pyk2 translocation did not result in its recruitment to lipid rafts. Two results support that Pyk2 translocation was independent of its kinase activity. First, Lck activity was required for TCR-induced Pyk2 translocation, but not for TCR-induced Pyk2 activation. Second, a kinase-dead Pyk2 mutant was equally translocated upon TCR triggering. In addition, Lck activity alone was insufficient to induce Pyk2 reorientation and activation, requiring the presence of at least one intact immunoreceptor tyrosine-based activation motif (ITAM). Despite the dependence on functional Lck and on phosphorylated ITAM for Pyk2 translocation, the ITAM-binding tyrosine kinase zeta-associated protein 70 (ZAP-70) was not essential. All these data suggest that, by translocating to the vicinity of the immune synapse, Pyk2 could play an essential role in T cell activation and polarized secretion of cytokines.
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Affiliation(s)
- David Sancho
- Servicio de Inmunología, Hospital de la Princesa, Madrid, Spain
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36
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Abstract
NO is a cytotoxic and immunomodulatory cytokine produced by macrophages and dendritic cells. We show that stimulation of murine and human macrophages with the heat shock proteins gp96 and hsp70 results in induction of inducible NO synthase and the production of NO. The release of NO by monocytes exposed to hsp60 has been documented previously. Immature, but not mature, dendritic cells respond in the same manner. The activity of heat shock proteins is relatively unaffected by an antagonist of LPS, and is abrogated by heat denaturation. Macrophages have been shown previously to produce NO in response to stimulation with IFN-gamma; stimulation of macrophages with mixtures of IFN-gamma and gp96 or hsp70 leads to a synergistic production of NO. The present observations extend the roles of these heat shock proteins in innate immune responses to another potent and highly conserved function of APC.
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Affiliation(s)
- Naveed N Panjwani
- Cellular and Molecular Immunology Group, Antigenics, Inc., Woburn, MA 01801. Center for Immunotherapy of Cancer and Infectious Diseases, University of Connecticut School of Medicine, Farmington, CT 06030
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37
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Affiliation(s)
- C Watts
- School of Life Sciences, University of Dundee, Dundee DD1 5EH, UK.
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38
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Maric M, Arunachalam B, Phan UT, Dong C, Garrett WS, Cannon KS, Alfonso C, Karlsson L, Flavell RA, Cresswell P. Defective antigen processing in GILT-free mice. Science 2001; 294:1361-5. [PMID: 11701933 DOI: 10.1126/science.1065500] [Citation(s) in RCA: 218] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
Processing of proteins for major histocompatibility complex (MHC) class II-restricted presentation to CD4-positive T lymphocytes occurs after they are internalized by antigen-presenting cells (APCs). Antigenic proteins frequently contain disulfide bonds, and their reduction in the endocytic pathway facilitates processing. In humans, a gamma interferon-inducible lysosomal thiol reductase (GILT) is constitutively present in late endocytic compartments of APCs. Here, we identified the mouse homolog of GILT and generated a GILT knockout mouse. GILT facilitated the processing and presentation to antigen-specific T cells of protein antigens containing disulfide bonds. The response to hen egg lysozyme, a model antigen with a compact structure containing four disulfide bonds, was examined in detail.
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Affiliation(s)
- M Maric
- Section of Immunobiology, Howard Hughes Medical Institute, Yale University School of Medicine, New Haven, CT 06520, USA
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39
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Abstract
Cyclic nucleotide second messengers (cAMP and cGMP) play a central role in signal transduction and regulation of physiologic responses. Their intracellular levels are controlled by the complex superfamily of cyclic nucleotide phosphodiesterase (PDE) enzymes. Continuing advances in our understanding of the molecular pharmacology of these enzymes has led to the development of selective inhibitors as therapeutic agents for disease states ranging from cancer and heart failure to depression and sexual dysfunction. Several PDE types have been identified as therapeutic targets for immune/inflammatory diseases. This article briefly reviews the available in vitro, preclinical, and clinical data supporting the potential for selective PDE inhibitors as immunomodulatory agents.
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Affiliation(s)
- D M Essayan
- Division of Clinical Trials Design and Analysis, Office of Therapeutics Research and Review, Center for Biologics Evaluation and Research, US Food and Drug Administration, Rockville, MD 20852, USA
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40
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Barrera C, Ye G, Espejo R, Gunasena S, Almanza R, Leary J, Crowe S, Ernst P, Reyes VE. Expression of cathepsins B, L, S, and D by gastric epithelial cells implicates them as antigen presenting cells in local immune responses. Hum Immunol 2001; 62:1081-91. [PMID: 11600214 DOI: 10.1016/s0198-8859(01)00281-6] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
Helicobacter pylori infection is linked to chronic gastritis, peptic ulcer and gastric carcinoma. During H. pylori infection, class II MHC expression by the gastric epithelium increases, as does the number of local CD4(+) T cells, which appear to be important in the associated pathogenesis. These observations suggested that the epithelium might present antigens to T cells. Thus, we sought to determine whether gastric epithelial cells process antigens to establish their function as local antigen presenting cells (APC). We examined a panel of gastric epithelial cell lines for expression of the antigen processing cathepsins B (CB), L (CL), S (CS), and D (CD). The mRNA for these enzymes were detected by RT-PCR and the enzymes in the gastric epithelial cells were identified by various independent methods. We corroborated the expression of CB and CD on gastric epithelial cells from human biopsy samples. The functions of these proteases were confirmed by assessing their ability to digest ovalbumin, a conventional dietary antigen, and proteins from H. pylori. In summary, multiple lines of evidence suggest gastric epithelial cells process antigens for presentation to CD4(+) T cells. To our knowledge, these are the first studies to document the antigen processing capacity of human gastric epithelial cells.
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Affiliation(s)
- C Barrera
- Department of Pediatrics, University of Texas Medical Branch, Galveston, TX, USA
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41
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Zhang T, Maekawa Y, Sakai T, Nakano Y, Ishii K, Hisaeda H, Kominami E, Katunuma N, Asao T, Himeno K. Splenic cathepsin L is maturated from the proform by interferon-gamma after immunization with exogenous antigens. Biochem Biophys Res Commun 2001; 283:499-506. [PMID: 11327729 DOI: 10.1006/bbrc.2001.4795] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The processing of foreign protein antigens into peptides requires the participation of various endo/lysosomal proteases in antigen-presenting cells (APCs). In this study, a proenzyme of cathepsin L, procathepsin L, was found to be present in the spleens of naive mice, as demonstrated by immunoblotting. Interestingly, the maturation of cathepsin L from procathepsin L was strongly induced when the host BALB/c mice were immunized with ovalbumin or soluble leishmanial antigen, despite the fact that mouse albumin, a kind of self-antigen, did not have such a potential. Furthermore, foreign antigens, but not self-antigens, could increase the activity of cathepsin L, probably being mediated by interferon-gamma, as demonstrated by in vivo and in vitro experiments. As cathepsin L matured, the efficiency of antigen processing was increased in APCs. These results suggest that endo/lysosomal cathepsin L plays an important role in the immune regulation via antigen processing even in peripheral lymphoid tissues as well as in the thymus.
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Affiliation(s)
- T Zhang
- Department of Parasitology and Immunology, University of Tokushima, School of Medicine, Kuramoto-cho 3, Tokushima, 770-8503, Japan
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42
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Abstract
We have analyzed the intracellular degradation of an immune complex after its FcgammaR-mediated uptake in antigen-presenting cells (APC). Mice that lack the cathepsins (Cat) S, L, B and D allowed us to assess the direct contribution of these individual proteases to the processing events observed. CatS and CatB mediate the bulk of degradation of the Ig-125I-labeled F(ab')2 immune complex delivered via FcgammaR, while CatL and CatD are dispensable. CatS and CatB are involved in independent processing pathways and can substitute in part for each other's absence. The combined ablation of both proteases reduces the rate of degradation observed by > 80 %. CatB is required for the generation of F(ab')23, a predominant degradation intermediate smaller by approximately 3 kDa than the 125I-labeled F(ab')2 itself. In addition, absence of CatB in vivo significantly affects the activity pattern of the remaining cysteine proteases. Thus, we conclude that CatB is a key enzyme for the proper degradation of an immune complex taken up by FcgammaR and for the control of protease activity in the endocytic pathway of APC.
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Affiliation(s)
- C Driessen
- Department of Pathology, Harvard Medical School, Boston 02115, USA
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43
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Zavasnik-Bergant V, Sekirnik A, Golouh R, Turk V, Kos J. Immunochemical localisation of cathepsin S, cathepsin L and MHC class II-associated p41 isoform of invariant chain in human lymph node tissue. Biol Chem 2001; 382:799-804. [PMID: 11517933 DOI: 10.1515/bc.2001.096] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Antigen presentation by MHC class II molecules requires cysteine proteases (CP) for two convergent proteolytic processes: stepwise degradation of the invariant chain (Ii) and generation of immunogenic peptides. Their activity is controlled by intracellular CP inhibitors, including presumably the p41 isoform of invariant chain (p41 Ii), which is in vitro a potent inhibitor of cathepsin L but not of cathepsin S. In order to evaluate the inhibitory potential of p41 Ii in antigen-presenting cells (APC), these three proteins were stained in lymph node tissue using specific monoclonal and polyclonal antibodies. The most abundant labelling was observed in subcapsular (cortical) and trabecular sinuses of the lymph node. In this area the most frequent APC were macrophages, as confirmed by the CD68 cell marker. Using confocal fluorescence microscopy, co-localisation of p41 Ii with cathepsin S, but not with cathepsin L was found in these cells. Our results are consistent with the hypothesis that cathepsin S participates in degradation of the invariant chain, but they do not support the association between cathepsin L and p41 Ii in APC.
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Affiliation(s)
- V Zavasnik-Bergant
- Department of Biochemistry and Molecular Biology, Jozef Stefan Institute, Jamova, Ljubljana, Slovenia
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44
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Abstract
Immunologic unresponsiveness (tolerance) is a key feature of the mucosal immune system, and deliberate vaccination by a mucosal route can effectively induce immune suppression. However, some bacterial-derived proteins, e.g. cholera toxin and the heat labile toxin of Escherichia coli, are immunogenic and immunomodulatory at mucosal surfaces and can effectively adjuvant immune responses to codelivered bystander antigens. This review summarizes some of the structural and biological characteristics of these toxins and provides examples of how these properties have been exploited for tolerance induction and mucosal vaccine development.
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Affiliation(s)
- C P Simmons
- Department of Biochemistry, Imperial College of Science Technology and Medicine, South Kensington, London SW7 2AZ, UK.
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45
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Yasutomo K, Lucas B, Germain RN. TCR signaling for initiation and completion of thymocyte positive selection has distinct requirements for ligand quality and presenting cell type. J Immunol 2000; 165:3015-22. [PMID: 10975810 DOI: 10.4049/jimmunol.165.6.3015] [Citation(s) in RCA: 39] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Thymocyte selection involves signaling by TCR engaging diverse self-peptide:MHC molecule ligands on various cell types in the cortex and medulla. Here we separately analyze early and late stages of selection to better understand how presenting cell type, ligand quality, and the timing of TCR signaling contribute to intrathymic differentiation. TCR transgenic CD4+CD8+ thymocytes (double positive (DP)) from MHC-deficient mice were stimulated using various presenting cells and ligands. The resulting CD69high cells were isolated and evaluated for maturation in reaggregate cultures with wild-type or MHC molecule-deficient thymic stroma with or without added hemopoietic dendritic cells (DC). Production of CD4+ T cells required TCR signaling in the reaggregates, indicating that transient recognition of self-ligands by DP is inadequate for full differentiation. DC bearing a potent agonist ligand could initiate positive selection, producing activated thymocytes that matured into agonist-responsive T cells in reaggregates lacking the same ligand. DC could also support the TCR signaling necessary for late maturation. These results argue that despite the negative role assigned to DC in past studies, neither the peptide:MHC molecule complexes present on DC nor any other signals provided by these cells stimulate only thymocyte death. These findings also indicate that unique epithelial ligands are not necessary for positive selection. They provide additional insight into the role of ligand quality in selection events and support the concept that following initiation of maturation from the DP state, persistent TCR signaling is characteristic of and perhaps required by T cells.
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MESH Headings
- Animals
- Antigen-Presenting Cells/classification
- Antigen-Presenting Cells/enzymology
- Antigen-Presenting Cells/immunology
- Antigen-Presenting Cells/metabolism
- Antigens, CD/biosynthesis
- Antigens, Differentiation, T-Lymphocyte/biosynthesis
- CD4 Antigens/biosynthesis
- CD4-Positive T-Lymphocytes/cytology
- CD4-Positive T-Lymphocytes/immunology
- CD4-Positive T-Lymphocytes/metabolism
- CD8 Antigens/biosynthesis
- Cell Aggregation/immunology
- Cell Differentiation/immunology
- Cell Survival/immunology
- Cells, Cultured
- Cytochrome c Group/immunology
- Cytochrome c Group/metabolism
- Dendritic Cells/enzymology
- Dendritic Cells/immunology
- Dendritic Cells/metabolism
- Histocompatibility Antigens Class II/metabolism
- Immunophenotyping
- Lectins, C-Type
- Ligands
- Lymphocyte Activation
- Major Histocompatibility Complex/immunology
- Mice
- Mice, Inbred C57BL
- Mice, Knockout
- Mice, Transgenic
- Peptides/agonists
- Peptides/immunology
- Peptides/metabolism
- Proto-Oncogene Proteins c-bcl-2/agonists
- Proto-Oncogene Proteins c-bcl-2/biosynthesis
- Receptors, Antigen, T-Cell/physiology
- Signal Transduction/immunology
- Stromal Cells/immunology
- Stromal Cells/metabolism
- T-Lymphocyte Subsets/cytology
- T-Lymphocyte Subsets/immunology
- T-Lymphocyte Subsets/metabolism
- Thymus Gland/cytology
- Thymus Gland/immunology
- Thymus Gland/metabolism
- Up-Regulation/immunology
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Affiliation(s)
- K Yasutomo
- Lymphocyte Biology Section, Laboratory of Immunology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD 20892, USA
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46
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Phan UT, Arunachalam B, Cresswell P. Gamma-interferon-inducible lysosomal thiol reductase (GILT). Maturation, activity, and mechanism of action. J Biol Chem 2000; 275:25907-14. [PMID: 10852914 DOI: 10.1074/jbc.m003459200] [Citation(s) in RCA: 159] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
We recently identified a gamma-interferon-inducible lysosomal thiol reductase (GILT), constitutively expressed in antigen-presenting cells, that catalyzes disulfide bond reduction both in vitro and in vivo and is optimally active at acidic pH. GILT is synthesized as a 35-kDa precursor, and following delivery to major histocompatibility complex (MHC) class II-containing compartments (MIICs), is processed to the mature 30-kDa form via cleavage of N- and C-terminal propeptides. The generation of MHC class II epitopes requires both protein denaturation and reduction of intra- and inter-chain disulfide bonds prior to proteolysis. GILT may be important in disulfide bond reduction of proteins delivered to MIICs and consequently in antigen processing. In this report we show that, like its mature form, precursor GILT reduces disulfide bonds with an acidic pH optimum, suggesting that it may also be involved in disulfide bond reduction in the endocytic pathway. We also show that processing of precursor GILT can be mediated by multiple lysosomal proteases and provide evidence that the mechanism of action of GILT resembles that of other thiol oxidoreductases.
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Affiliation(s)
- U T Phan
- Section of Immunobiology, Howard Hughes Medical Institute, Yale University School of Medicine, New Haven, Connecticut 06510, USA
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47
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Bertho N, Drénou B, Laupeze B, Berre CL, Amiot L, Grosset JM, Fardel O, Charron D, Mooney N, Fauchet R. HLA-DR-mediated apoptosis susceptibility discriminates differentiation stages of dendritic/monocytic APC. J Immunol 2000; 164:2379-85. [PMID: 10679073 DOI: 10.4049/jimmunol.164.5.2379] [Citation(s) in RCA: 45] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Professional APC are characterized by their ability to present peptide via HLA class II in the presence of costimulatory molecules (CD40, CD80, and CD86). The efficiency of Ag presentation can be classed as follows: mature dendritic cells (DC) are most efficient, immature DC and macrophages are intermediate, and monocytes are considered poor APC. There is a large body of evidence demonstrating that HLA-DR transmits signals in the APC. In this study, we have addressed the question of the outcome of HLA-DR signals on APC of the monocyte/DC lineages throughout their differentiation from immature to mature APC. DC were generated from both monocytes and CD34+ cells of the same individual, macrophages were differentiated from monocytes. Immunophenotypical analysis clearly distinguished these populations. HLA-DR-mediated signals led to marked apoptosis in mature DC of either CD34 or monocytic origin. Significantly less apoptosis was observed in immature DC of either origin. Nonetheless, even immature DC were more susceptible to HLA-DR-mediated apoptosis than macrophages, whereas monocytes were resistant to HLA-DR-mediated apoptosis. The mechanism of HLA-DR-mediated apoptosis was independent of caspase activation. Taken together, these data lead to the notion that signals generated via HLA-DR lead to the demise of mature professional APC, thereby providing a means of limiting the immune response.
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Affiliation(s)
- N Bertho
- Laboratoire Universitaire d'Hématologie et de Biologie des Cellules Sanguines, Institut National de la Santé et de la Recherche Médicale CRI 9606-UPRES EA 22-33, Rennes, France
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48
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Reijonen H, Elliott JF, van Endert P, Nepom G. Differential presentation of glutamic acid decarboxylase 65 (GAD65) T cell epitopes among HLA-DRB1*0401-positive individuals. J Immunol 1999; 163:1674-81. [PMID: 10415074] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Subscribe] [Scholar Register] [Indexed: 02/13/2023]
Abstract
Glutamic acid decarboxylase 65 (GAD65) is one of the major autoantigens in type 1 diabetes. We investigated whether there is variation in the processing of GAD65 epitopes between individuals with similar HLA backgrounds and whether the processing characteristics of certain immunogenic epitopes are different in distinct APC subpopulations. Using DR401-restricted T cell hybridomas specific for two immunogenic GAD65 epitopes (115-127 and 274-286), we demonstrate an epitope-specific presentation pattern in human B-lymphoblastoid cell lines (B-LCL). When pulsed with the GAD protein, some DRB1*0401-positive B-LCL, which presented GAD65 274-286 epitope efficiently, were unable to present the GAD65 115-127 epitope. However, all B-LCL presented synthetic peptides corresponding to either GAD epitope. In addition, when pulsed with human serum albumin, all cell lines gave equal stimulation of a DR4-restricted human serum albumin-specific T hybridoma. GAD65-transfected cell lines displayed the same presentation phenotype, showing that lack of the presentation of the 115-127 epitope was not due to inefficient uptake of the protein. Blood mononuclear adherent cells, B cells, or dendritic cells derived from the same individual displayed the same presentation pattern as observed in B cell lines, suggesting that the defect most likely is genetically determined. Therefore, individual differences in Ag processing may result in the presentation of distinct set of peptides derived from an autoantigen such as GAD65. This may be an important mechanism for the deviation of the immune response either into a regulatory pathway or into an inflammatory autoimmune reactivity.
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Affiliation(s)
- H Reijonen
- Virginia Mason Research Center, Seattle, WA 98101, USA.
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49
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Litherland SA, Xie XT, Hutson AD, Wasserfall C, Whittaker DS, She JX, Hofig A, Dennis MA, Fuller K, Cook R, Schatz D, Moldawer LL, Clare-Salzler MJ. Aberrant prostaglandin synthase 2 expression defines an antigen-presenting cell defect for insulin-dependent diabetes mellitus. J Clin Invest 1999; 104:515-23. [PMID: 10449443 PMCID: PMC408519 DOI: 10.1172/jci4852] [Citation(s) in RCA: 83] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/1998] [Accepted: 07/13/1999] [Indexed: 12/21/2022] Open
Abstract
Prostaglandins (PGs) are lipid molecules that profoundly affect cellular processes including inflammation and immune response. Pathways contributing to PG output are highly regulated in antigen-presenting cells such as macrophages and monocytes, which produce large quantities of these molecules upon activation. In this report, we demonstrate aberrant constitutive expression of the normally inducible cyclooxygenase PG synthase 2 (PGS(2)/ COX-2) in nonactivated monocytes of humans with insulin-dependent diabetes mellitus (IDDM) and those with islet autoantibodies at increased risk of developing this disease. Constitutive PGS(2) appears to characterize a high risk for diabetes as it correlates with and predicts a low first-phase insulin response in autoantibody-positive subjects. Abnormal PGS(2) expression in at-risk subjects affected immune response in vitro, as the presence of a specific PGS(2) inhibitor, NS398, significantly increased IL-2 receptor alpha-chain (CD25) expression on phytohemagglutinin-stimulated T cells. The effect of PGS(2) on CD25 expression was most profound in subjects expressing both DR04 and DQbeta0302 high-risk alleles, suggesting that this cyclooxygenase interacts with diabetes-associated MHC class II antigens to limit T-cell activation. These results indicate that constitutive PGS(2) expression in monocytes defines an antigen-presenting cell defect affecting immune response, and that this expression is a novel cell-associated risk marker for IDDM.
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Affiliation(s)
- S A Litherland
- Department of Immunology, Pathology, and Laboratory Medicine, College of Medicine, College of Medicine, University of Florida, Gainesville 32610, USA
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50
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Lu HT, Yang DD, Wysk M, Gatti E, Mellman I, Davis RJ, Flavell RA. Defective IL-12 production in mitogen-activated protein (MAP) kinase kinase 3 (Mkk3)-deficient mice. EMBO J 1999; 18:1845-57. [PMID: 10202148 PMCID: PMC1171270 DOI: 10.1093/emboj/18.7.1845] [Citation(s) in RCA: 312] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
The p38 mitogen-activated protein kinase (MAPK) pathway, like the c-Jun N-terminal kinase (JNK) MAPK pathway, is activated in response to cellular stress and inflammation and is involved in many fundamental biological processes. To study the role of the p38 MAPK pathway in vivo, we have used homologous recombination in mice to inactivate the Mkk3 gene, one of the two specific MAPK kinases (MAPKKs) that activate p38 MAPK. Mkk3(-/-) mice were viable and fertile; however, they were defective in interleukin-12 (IL-12) production by macrophages and dendritic cells. Interferon-gamma production following immunization with protein antigens and in vitro differentiation of naive T cells is greatly reduced, suggesting an impaired type I cytokine immune response. The effect of the p38 MAPK pathway on IL-12 expression is at least partly transcriptional, since inhibition of this pathway blocks IL-12 p40 promoter activity in macrophage cell lines and IL-12 p40 mRNA is reduced in MKK3-deficient mice. We conclude that the p38 MAP kinase, activated through MKK3, is required for the production of inflammatory cytokines by both antigen-presenting cells and CD4(+) T cells.
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Affiliation(s)
- H T Lu
- Howard Hughes Medical Institute and Section of Immunobiology, Yale University School of Medicine, New Haven, CT 06520, USA
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