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Eguchi M, Sekiya Y, Kikuchi Y, Takaya A, Yamamoto T, Matsui H. ExpressedSalmonellaantigens within macrophages enhance the proliferation of CD4+and CD8+T lymphocytes by means of bystander dendritic cells. ACTA ACUST UNITED AC 2007; 50:411-20. [PMID: 17573927 DOI: 10.1111/j.1574-695x.2007.00275.x] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
ATP-dependent Lon protease-deficient Salmonella enterica serovar Typhimurium (strain CS2022) appeared to invade successfully the mesenteric lymph nodes (MLN) and Peyer's patches (PP) of BALB/c mice and appeared to be easily eradicated by the host after oral immunization. As detected by flow cytometry, the population of major histocompatibility complex class I (MHC-I)-expressing macrophages and dendritic cells (DCs) was increased in the PP of mice immunized with CS2022 on day 6 after immunization. Thereafter, the population of splenic surface CD69(+) T lymphocytes prepared from mice immunized with CS2022 6 weeks prior to measurement increased as a result of the administration of the extracellular vesicles of RAW264.7 macrophage-like cells derived by Salmonella challenge. In addition, the proliferation of CD8(+) and even of CD4(+)T cells isolated from mouse spleens immunized with CS2022 was enhanced after cocultivation with naive DCs in the presence of the extracellular vesicles. These findings indicate that the extracellular vesicles prepared from the Salmonella-challenged macrophages carried salmonellae antigens to bystander DCs, thereby stimulating T-cell responses. Therefore, as antigen presentation after phagocytosis should be a central process in the T-cell activation that occurs in response to Salmonella infection, an oral immunization with CS2022 sufficiently induces T cell-mediated immunity in mice.
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Affiliation(s)
- Masahiro Eguchi
- Kitasato Institute for Life Sciences and Graduate School of Infection Control Sciences, Kitasato University, Tokyo, Japan
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52
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Bueno SM, González PA, Schwebach JR, Kalergis AM. T cell immunity evasion by virulent Salmonella enterica. Immunol Lett 2007; 111:14-20. [PMID: 17583359 DOI: 10.1016/j.imlet.2007.05.003] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2007] [Revised: 04/13/2007] [Accepted: 05/11/2007] [Indexed: 12/30/2022]
Abstract
Salmonella enterica are Gram-negative bacteria that cause systemic disease in their specific hosts. One of the recently appreciated features of Salmonella pathogenicity is the capacity of the bacteria to impair host adaptive immunity by interfering with DC function and T cell activation. It is likely that this feature of virulent Salmonella is needed to promote systemic dissemination in the host. Recent studies have suggested explanations for some of the molecular mechanisms developed by virulent Salmonella to impair DC and T cell function. Several of these mechanisms require the expression of virulence genes encoded within Salmonella pathogenicity islands. Targeted deletion of these genes diminishes Salmonella pathogenicity and leads to efficient activation of T cells by Salmonella-infected DCs. In this review, recent data that support the subversion of DC function by Salmonella as a means to evade host adaptive immunity and cause systemic infection are discussed. These new findings suggest a new pathogenesis model with DCs as key targets for Salmonella virulence factors.
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Affiliation(s)
- Susan M Bueno
- Millennium Nucleus on Immunology and Immunotherapy, Departamento de Genética Molecular y Microbiología, Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile, Chile
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53
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Abstract
It is now appreciated that dendritic cells (DCs) play a primary role in oral tolerance and defense against mucosal pathogens. Specific DC subpopulations are localized to discrete regions within primary inductive tissues, like the Peyer's patch and mesenteric lymph node, and effector sites, like the lamina propria, and may have unique roles in driving regulatory, effector and memory T cell responses. Certain DC subpopulations may also help maintain T cell responses at sites of abnormal intestinal inflammation. While early in our understanding, knowledge about the involvement of DC subpopulations in the regulation of mucosal immunity may well provide a basis for the development of novel vaccines and therapeutics.
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Affiliation(s)
- Cecilia Johansson
- Laboratory of Molecular Immunology, NIAID, NIH, 10 Center Drive, 10-11N214, Bethesda, 20892 MD, USA.
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54
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Zhao C, Wood MW, Galyov EE, Höpken UE, Lipp M, Bodmer HC, Tough DF, Carter RW. Salmonella typhimurium infection triggers dendritic cells and macrophages to adopt distinct migration patterns in vivo. Eur J Immunol 2007; 36:2939-50. [PMID: 17048271 DOI: 10.1002/eji.200636179] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
The presence of an anti-bacterial T cell response and evidence of bacterial products in inflamed joints of reactive arthritis patients suggests an antigen transportation role in this disease for macrophages and dendritic cells. We have investigated the functional properties and in vivo migration of macrophages and DC after infection with Salmonella enterica serovar Typhimurium (S. typhimurium). BM-derived macrophages and DC displayed enhanced expression of costimulatory molecules (CD40 and CD86) and increased production of pro-inflammatory cytokines (TNF-alpha, IL-6 and IL-12p40) and nitric oxide after infection. Upon adoptive transfer into mice, infected DC migrated to lymphoid tissues and induced an anti-Salmonella T cell response, whereas infected macrophages did not. Infection of DC with S. typhimurium was associated with strong up-regulation of the chemokine receptor CCR7 and acquisition of responsiveness to chemokines acting through this receptor. Moreover, S. typhimurium-infected CCR7-deficient DC were unable to migrate to lymph nodes after adoptive transfer, although they did reach the spleen. Our data demonstrate distinct roles for macrophages and DC as antigen transporters after S. typhimurium infection and a dependence on CCR7 for migration of DC to lymph nodes after bacterial infection.
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Affiliation(s)
- Chunfang Zhao
- The Edward Jenner Institute for Vaccine Research, Compton, Newbury, UK
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55
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Abstract
Salmonella species cause substantial morbidity, mortality and burden of disease globally. Infections with Salmonella species cause multiple clinical syndromes. Central to the pathophysiology of all human salmonelloses is the induction of a strong host innate immune/inflammatory response. Whether this ultimately reflects an adaptive advantage to the host or pathogen is not clear. However, it is evident that both the host and pathogen have evolved mechanisms of triggering host responses that are detrimental to the other. In this review, we explore some of the host and pathogenic mechanisms mobilized in the two predominant clinical syndromes associated with infection with Salmonella enterica species: enterocolitis and typhoid.
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Affiliation(s)
- Bryan Coburn
- Michael Smith Laboratories, University of British Columbia, Vancouver, British Columbia, Canada
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56
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Liu GW, Ma HX, Wu Y, Zhao Y. The nonopsonic allogeneic cell phagocytosis of macrophages detected by flow cytometry and two photon fluorescence microscope. Transpl Immunol 2006; 16:220-6. [PMID: 17138057 DOI: 10.1016/j.trim.2006.09.023] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2006] [Revised: 08/21/2006] [Accepted: 09/08/2006] [Indexed: 10/24/2022]
Abstract
Phagocytosis, one of the apparent functions for macrophages, represents an early and crucial event in triggering host defenses against invading pathogens as well as allo- or xenogeneic rejection. Now, some methods have been used in detecting the opsonic phagocytosis of macrophages in xenogeneic settings. Efficient nonopsonic phagocytosis analysis method has not been established yet. In the present studies, allogeneic lymphocytes pre-labeled with 5-(and-6)-carboxyfluorescein diacetate succinimidyl ester (CFSE) or derived from green fluorescent protein transgeneic B6 mice (GFP-B6 mice) were co-incubated with primary murine peritoneal macrophages (PEMs) for 1-2 h or were injected into murine peritoneal cavity for 30 to 240 min. Assays by flow cytometry (FCM) and two photon laser scanning microscope (TPM) showed an efficient uptake of both allogeneic lymphocytes and xenogeneic chicken red blood cells. The continuing process of nonopsonic phagocytosis of allogeneic lymphocytes by PEMs was recorded by TPM. Furthermore, the phenotype differences of PEMs with or without phagocytosis of allogeneic cells were determined by three-color FCMs. Significantly upregulated expressions of CD11b, CD44, TLR2 and TLR4 on PEMs were observed as early as 6 h after phagocytosis of allogeneic cells. Our present data indicated that the FCM and TPM combined method is a practical approach to detect macrophage nonopsonic phagocytosis of allogeneic lymphocytes and to identify the phenotype alteration of macrophages after phagocytosis.
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Affiliation(s)
- Guang-Wei Liu
- Transplantation Biology Research Division, State Key Laboratory of Biomembrane and Membrane Biotechnology, Institute of Zoology, Chinese Academy of Sciences, Beijing, China
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57
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Stecher B, Paesold G, Barthel M, Kremer M, Jantsch J, Stallmach T, Heikenwalder M, Hardt WD. Chronic Salmonella enterica serovar Typhimurium-induced colitis and cholangitis in streptomycin-pretreated Nramp1+/+ mice. Infect Immun 2006; 74:5047-57. [PMID: 16926396 PMCID: PMC1594839 DOI: 10.1128/iai.00072-06] [Citation(s) in RCA: 58] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Salmonella enterica subspecies 1 serovar Typhimurium is an enteric bacterial pathogen infecting a broad range of hosts. In susceptible Nramp1(-/-) (Slc11alpha1(-/-)) mice, serovar Typhimurium cannot efficiently colonize the intestine but causes a systemic typhoid-like infection. However, after pretreatment with streptomycin, these susceptible (C57BL/6 and BALB/c) mice develop acute serovar Typhimurium-induced colitis (M. Barthel et al., Infect. Immun. 71:2839-2858, 2003). It was not clear whether resistant Nramp1(+/+) (Slc11alpha1(+/+)) mouse strains would similarly develop colitis. Here we compared serovar Typhimurium infection in streptomycin-pretreated susceptible (C57BL/6) and resistant (DBA/2 and 129Sv/Ev) mouse strains: We found that acute colitis (days 1 and 3 postinfection) is strikingly similar in susceptible and resistant mice. In 129Sv/Ev mice we followed the serovar Typhimurium infection for as long as 6 weeks. After the initial phase of acute colitis, these animals developed chronic crypt-destructive colitis, including ulceration, crypt abscesses, pronounced mucosal and submucosal infiltrates, overshooting regeneration of the epithelium, and crypt branching. Moreover, we observed inflammation of the gall duct epithelium (cholangitis) in the 129Sv/Ev mice between days 14 and 43 of infection. Cholangitis was not attributable to side effects of the streptomycin treatment. Furthermore, chronic infection of 129Sv/Ev mice in a typhoid fever model did not lead to cholangitis. We propose that streptomycin-pretreated 129Sv/Ev mice provide a robust murine model for chronic enteric salmonellosis including complications such as cholangitis.
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Affiliation(s)
- Bärbel Stecher
- Institute of Microbiology, ETH Zürich, Wolfgang-Pauli Strasse 10, 8093 Zürich, Switzerland
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58
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Abstract
Salmonella enterica serovar Typhi causes typhoid fever, a serious life-threatening systemic infection. In mice, a similar disease is caused by Salmonella enterica serovar Typhimurium. During typhoid fever, soon after attachment to the mucosal surface of the gut, bacteria come into contact with the dendritic cells (DCs). The ability to sample antigens, process and present them to naïve and mature T cells, in the context of major histocompatibility complex molecules, makes DCs indispensable for mounting a specific and efficient immune response to invading pathogens. These bacteria, however, have evolved a number of mechanisms to interfere with or subvert DC functions. This review aims to describe how Salmonella clashes with dendritic cells at different stages of infection as well as the war strategies of these two opposing sides.
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Affiliation(s)
- Marta Biedzka-Sarek
- Department of Bacteriology and Immunology, Haartman Institute, 00014 University of Helsinki, Helsinki, Finland.
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59
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Johansson C, Ingman M, Jo Wick M. Elevated neutrophil, macrophage and dendritic cell numbers characterize immune cell populations in mice chronically infected with Salmonella. Microb Pathog 2006; 41:49-58. [PMID: 16782300 DOI: 10.1016/j.micpath.2006.03.004] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2005] [Revised: 03/15/2006] [Accepted: 03/16/2006] [Indexed: 01/22/2023]
Abstract
The present study characterizes immune cell populations in mice chronically infected with Salmonella. Mice were characterized as chronically infected based on persistently high titers of Salmonella-reactive immunoglobulins in the serum >6 months after a single oral dose of S. enterica serovar Typhimurium. These mice had a visibly enlarged spleen but not liver, while both organs harbored bacteria and had increased total cellularity up to 11 months post-infection. Flow cytometry analysis revealed significantly elevated numbers of neutrophils, dendritic cells (DC) and macrophages in the spleen of chronically infected mice. In contrast, no significant increase in the absolute number of T and B cells was apparent in the spleen and DX5+ cells, which includes NK cells, some NK T cells and possibly some activated T cells, appears to correlate with chronic Salmonella infection in the liver but not the spleen. In situ analyses revealed that CD8alpha+ DC and Gr-1+ cells (neutrophils) increased in the splenic red pulp of chronically infected mice. In addition, Gr-1+ cells, CD68+ cells and CD11c+ cells (DC), the latter lacking detectable staining for CD8alpha and CD4, accumulated around hepatic blood vessels and in the hepatic network in the liver of mice chronically harboring bacteria. These data provide insight into changes that occur within immune cell populations, most notably within splenic and hepatic phagocytic cell populations, that accompany chronic infection with the intracellular bacterium Salmonella.
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Affiliation(s)
- Cecilia Johansson
- Department of Cell and Molecular Biology, Section for Immunology, Lund University, 221 84 Lund, Sweden
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60
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Knodler LA, Bestor A, Ma C, Hansen-Wester I, Hensel M, Vallance BA, Steele-Mortimer O. Cloning vectors and fluorescent proteins can significantly inhibit Salmonella enterica virulence in both epithelial cells and macrophages: implications for bacterial pathogenesis studies. Infect Immun 2005; 73:7027-31. [PMID: 16177386 PMCID: PMC1230934 DOI: 10.1128/iai.73.10.7027-7031.2005] [Citation(s) in RCA: 54] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Plasmid vectors and fluorescent protein reporter systems are commonly used in the study of bacterial pathogenesis. Here we show that they can impair the ability of Salmonella enterica serovar Typhimurium to productively infect either cultured mammalian cells or mice. This has significant implications for studies that rely on these systems.
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Affiliation(s)
- Leigh A Knodler
- Laboratory of Intracellular Parasites, NIAID, NIH, Rocky Mountain Laboratories, Hamilton, MT 59840,USA
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61
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Depaolo RW, Lathan R, Rollins BJ, Karpus WJ. The chemokine CCL2 is required for control of murine gastric Salmonella enterica infection. Infect Immun 2005; 73:6514-22. [PMID: 16177325 PMCID: PMC1230974 DOI: 10.1128/iai.73.10.6514-6522.2005] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Salmonella enterica is a gram-negative intracellular pathogen that can cause a variety of diseases ranging from gastroenteritis to typhoid fever. The Typhimurium serotype causes gastroenteritis in humans; however, infection of mice results in an enteric fever that resembles human typhoid fever and has been used as a model for typhoid fever. The present study examined the role of the chemokine CCL2 in the control of Salmonella infection. Upon infection with salmonellae, mucosal expression of CCL2 is rapidly up-regulated, followed by systemic expression in the spleen. CCL2(-/-) mice became moribund earlier and had a higher rate of mortality compared to wild-type C57BL/6 mice. Moreover, CCL2(-/-) mice had significantly higher levels of bacteria in the liver compared to wild-type controls. Mucosal and serum interleukin-6 and tumor necrosis factor alpha levels were elevated in CCL2(-/-) mice compared to wild-type mice. In vitro analysis demonstrated that CCL2(-/-) macrophages infected with salmonellae resulted in dysregulated cytokine production compared to macrophages derived from wild-type mice. These data are the first to directly demonstrate CCL2 as a critical factor for immune responses and survival following S. enterica infection.
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Affiliation(s)
- R William Depaolo
- Department of Pathology, Northwestern University, Feinberg School of Medicine, Chicago, IL 60611, USA
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62
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Sundquist M, Wick MJ. TNF-alpha-dependent and -independent maturation of dendritic cells and recruited CD11c(int)CD11b+ Cells during oral Salmonella infection. THE JOURNAL OF IMMUNOLOGY 2005; 175:3287-98. [PMID: 16116221 DOI: 10.4049/jimmunol.175.5.3287] [Citation(s) in RCA: 51] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
Maturation of dendritic cells (DC) is crucial for their ability to induce adaptive immunity. Although several mediators of DC maturation have been found, their contributions to DC maturation during infection are poorly understood. In this study we show that murine conventional (CD11c(high)) DC up-regulate costimulatory molecules in a subset-specific manner after oral Salmonella infection. Although both CD8alpha+ and CD8alpha- subsets increase CD86 expression, CD40 was preferentially up-regulated on CD8alpha+ DC, and CD80 was preferentially increased on CD8alpha- DC. In addition, high levels of CD80 and CD86 were found on CD11c(int)CD11b+ cells that accumulated in infected organs. Costimulatory molecules were simultaneously induced on CD11c(high) and CD11c(int)CD11b+ cells in Peyer's patches, mesenteric lymph nodes and spleen 5 days after infection despite different kinetics of peak bacterial burden in these organs. Up-regulation of costimulatory molecules occurred on all DC within the respective subset. Moreover, <1% of CD11c-expressing cells associated with Salmonella expressing enhanced GFP in vivo. Thus, DC maturation did not depend on bacterial uptake. Rather, infection-induced up-regulation of CD80, CD86, and CD40 on CD11c-expressing cells of mesenteric lymph nodes was dependent on TNFR type I (TNFRI) signaling. Although indirect up-regulation of costimulatory molecules on DC and CD11c(int)CD11b+ cells was TNFRI dependent, cells directly associated with Salmonella were able to mature independently of TNFRI signaling. Thus, Salmonella-induced TNF-alpha is an important mediator of indirect DC maturation during infection, whereas a TNF-alpha-independent maturation pathway contributes to direct maturation of bacteria-associated DC.
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Affiliation(s)
- Malin Sundquist
- Department of Clinical Immunology, Goteborg University, Goteborg, Sweden
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63
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Kalupahana RS, Mastroeni P, Maskell D, Blacklaws BA. Activation of murine dendritic cells and macrophages induced by Salmonella enterica serovar Typhimurium. Immunology 2005; 115:462-72. [PMID: 16011515 PMCID: PMC1782185 DOI: 10.1111/j.1365-2567.2005.02180.x] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
Macrophages and dendritic cells (DCs) are antigen-presenting cells (APCs), and the direct involvement of both cell types in the immune response to Salmonella has been identified. In this study we analysed the phenotypic and functional changes that take place in murine macrophages and DCs in response to live and heat-killed Salmonella enterica serovar Typhimurium. Both types of cell secreted proinflammatory cytokines and nitric oxide (NO) in response to live and heat-killed salmonellae. Bacterial stimulation also resulted in up-regulation of costimulatory molecules on macrophages and DCs. The expression of major histocompatibility complex (MHC) class II molecules by macrophages and DCs was differentially regulated by interferon (IFN)-gamma and salmonellae. Live and heat-killed salmonellae as well as lipopolysaccharide (LPS) inhibited the up-regulation of MHC class II expression induced by IFN-gamma on macrophages but not on DCs. Macrophages as well as DCs presented Salmonella-derived antigen to CD4 T cells, although DCs were much more efficient than macrophages at stimulating CD4 T-cell cytokine release. Macrophages are effective in the uptake and killing of bacteria whilst DCs specialize in antigen presentation. This study showed that the viability of salmonellae was not essential for activation of APCs but, unlike live bacteria, prolonged contact with heat-killed bacteria was necessary to obtain maximal expression of the activation markers studied.
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Affiliation(s)
- Ruwani Sagarika Kalupahana
- Centre for Veterinary Science, Department of Veterinary Medicine, University of Cambridge, Cambridge, UK.
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64
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Ravindran R, McSorley SJ. Tracking the dynamics of T-cell activation in response to Salmonella infection. Immunology 2005; 114:450-8. [PMID: 15804280 PMCID: PMC1782102 DOI: 10.1111/j.1365-2567.2005.02140.x] [Citation(s) in RCA: 70] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
Despite the current availability of Salmonella vaccines, typhoid fever remains a significant public health problem in developing countries. A greater understanding of T-cell activation and the development of immunological memory during Salmonella infection should lead to the development of more effective prophylactic intervention. Here, we review recent literature on the initiation, expansion and memory development of T-cell responses using the mouse model of typhoid. We pay particular attention to strategies for tracking T-cell responses in vivo and ex vivo, and suggest models to integrate some these studies.
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Affiliation(s)
- Rajesh Ravindran
- Department of Medicine, Division of Immunology, University of Connecticut Health Center, Farmington, CT 06030, USA.
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65
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Fu G, Wijburg OLC, Cameron PU, Price JD, Strugnell RA. Salmonella enterica Serovar Typhimurium infection of dendritic cells leads to functionally increased expression of the macrophage-derived chemokine. Infect Immun 2005; 73:1714-22. [PMID: 15731072 PMCID: PMC1064904 DOI: 10.1128/iai.73.3.1714-1722.2005] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Gene expression in murine dendritic cells (DCs) infected with green fluorescent protein-expressing Salmonella enterica serovar Typhimurium BRD509 was studied by mRNA differential display. Infected DCs were sorted from uninfected cells by flow cytometry. The mRNA expression patterns of infected and uninfected cells revealed a number of differentially expressed transcripts, which included the macrophage-derived chemokine (MDC). Up-regulation of MDC transcription in infected DCs was confirmed by Northern blotting, and the kinetics of MDC expression was examined by real-time reverse transcription-PCR, with which 31- and 150-fold increases were detected at 2 and 6 h postinfection, respectively. The increased release by DCs of MDC into culture media was detected by an enzyme-linked immunosorbent assay. The biological activity of MDC was investigated in in vitro and in vivo assays. In vitro, supernatants from S. enterica serovar Typhimurium-infected DCs were chemoattractive to T cells, and neutralization of MDC in these supernatants inhibited T-cell migration. Passive transfer of anti-MDC antibody to mice infected with BRD509 revealed that neither growth of the bacterium nor resistance of the mice to reinfection was affected and that in vivo inhibition of MDC did not affect T-cell responses, as measured by the gamma interferon ELISPOT method 3 days after challenge infection.
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Affiliation(s)
- Guo Fu
- CRC for Vaccine Technology, Parkville, Victoria 3010, Australia
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66
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Kirby AC, Sundquist M, Wick MJ. In vivo compartmentalization of functionally distinct, rapidly responsive antigen-specific T-cell populations in DNA-immunized or Salmonella enterica serovar Typhimurium-infected mice. Infect Immun 2004; 72:6390-400. [PMID: 15501769 PMCID: PMC523063 DOI: 10.1128/iai.72.11.6390-6400.2004] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The location and functional properties of antigen-specific memory T-cell populations in lymphoid and nonlymphoid compartments following DNA immunization or infection with Salmonella were investigated. Epitope-specific CD8+ -T-cell expansion and retention during the memory phase were analyzed for DNA-immunized mice by use of a 5-h peptide restimulation assay. These data revealed that epitope-specific gamma interferon (IFN-gamma)-positive CD8+ T cells occur at higher frequencies in the spleen, liver, and blood than in draining or peripheral lymph nodes during the expansion phase. Moreover, this distribution is maintained into long-term memory. The location and function of both CD4+ and CD8+ Salmonella-specific memory T cells in mice who were given a single dose of Salmonella enterica serovar Typhimurium was also quantitated by an ex vivo restimulation with bacterial lysate to detect the total Salmonella-specific memory pool. Mice immunized up to 6 months previously with S. enterica serovar Typhimurium had bacterium-specific CD4+ T cells that were capable of producing IFN-gamma or tumor necrosis factor alpha (TNF-alpha) at each site analyzed. Similar findings were observed for CD8+ T cells that were capable of producing IFN-gamma, while a much lower frequency and more restricted distribution were associated with TNF-alpha-producing CD8+ T cells. This study is the first to assess the frequencies, locations, and functions of both CD4+ and CD8+ memory T-cell populations in the same Salmonella-infected individuals and demonstrates the organ-specific functional compartmentalization of memory T cells after Salmonella infection.
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Affiliation(s)
- Alun C Kirby
- Department of Cell and Molecular Biology, Lund University, Sweden
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67
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Tobar JA, González PA, Kalergis AM. SalmonellaEscape from Antigen Presentation Can Be Overcome by Targeting Bacteria to Fcγ Receptors on Dendritic Cells. THE JOURNAL OF IMMUNOLOGY 2004; 173:4058-65. [PMID: 15356155 DOI: 10.4049/jimmunol.173.6.4058] [Citation(s) in RCA: 96] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
Dendritic cells (DCs) are professional APCs with the unique ability to activate naive T cells, which is required for initiation of the adaptive immune response against pathogens. Therefore, interfering with DC function would be advantageous for pathogen survival and dissemination. In this study we provide evidence suggesting that Salmonella enterica serovar typhimurium, the causative agent of typhoid disease in the mouse, interferes with DC function. Our results indicate that by avoiding lysosomal degradation, S. typhimurium impairs the ability of DCs to present bacterial Ags on MHC class I and II molecules to T cells. This process could correspond to a novel mechanism developed by this pathogen to evade adaptive immunity. In contrast, when S. typhimurium is targeted to FcgammaRs on DCs by coating bacteria with Salmonella-specific IgG, bacterial Ags are efficiently processed and presented on MHC class I and class II molecules. This enhanced Ag presentation leads to a robust activation of bacteria-specific T cells. Laser confocal microscopy experiments show that virulent S. typhimurium is rerouted to the lysosomal degradation pathway of DCs when internalized through FcgammaR. These observations are supported by electron microscopy studies demonstrating that internalized S. typhimurium shows degradation signs only when coated with IgG and captured by FcgammaRs on DCs. Therefore, our data support a potential role for bacteria-specific IgG on the augmentation of Ag processing and presentation by DCs to T cells during the immune response against intracellular bacteria.
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Affiliation(s)
- Jaime A Tobar
- Departamento de Genética Molecular y Microbiología, Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile, Santiago, Chile
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68
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Diaz-Quiñonez A, Martin-Orozco N, Isibasi A, Ortiz-Navarrete V. Two Salmonella OmpC K(b)-restricted epitopes for CD8+-T-cell recognition. Infect Immun 2004; 72:3059-62. [PMID: 15102821 PMCID: PMC387851 DOI: 10.1128/iai.72.5.3059-3062.2004] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
We report the identification of two peptides from Salmonella OmpC porin that can bind to major histocompatibility complex class I K(b) molecules and are targets of cytotoxic T lymphocytes from Salmonella-infected mice. These peptides are conserved in gram-negative bacterial porins and are the first Salmonella porin-specific epitopes described for possible CD8(+)-T-cell elimination of infected cells.
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Affiliation(s)
- Alberto Diaz-Quiñonez
- Departamento de Biomedicina Molecular, Centro de Investigación y Estudios Avanzados (CINVESTAV), 07000 Mexico City, Mexico
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69
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Turner BC, Hemmila EM, Beauchemin N, Holmes KV. Receptor-dependent coronavirus infection of dendritic cells. J Virol 2004; 78:5486-90. [PMID: 15113927 PMCID: PMC400329 DOI: 10.1128/jvi.78.10.5486-5490.2004] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
In several mammalian species, including humans, coronavirus infection can modulate the host immune response. We show a potential role of dendritic cells (DC) in murine coronavirus-induced immune modulation and pathogenesis by demonstrating that the JAW SII DC line and primary DC from BALB/c mice and p/p mice with reduced expression of the murine coronavirus receptor, murine CEACAM1a, are susceptible to murine coronavirus infection by a receptor-dependent pathway.
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Affiliation(s)
- Brian C Turner
- Department of Microbiology, University of Colorado Health Sciences Center, 4200 East 9th Avenue, Denver, CO 80262, USA
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70
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van der Velden AWM, Velasquez M, Starnbach MN. Salmonella rapidly kill dendritic cells via a caspase-1-dependent mechanism. THE JOURNAL OF IMMUNOLOGY 2004; 171:6742-9. [PMID: 14662878 DOI: 10.4049/jimmunol.171.12.6742] [Citation(s) in RCA: 97] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Dendritic cells provide a critical link between innate and acquired immunity. In this study, we demonstrate that the bacterial pathogen Salmonella enterica serovar Typhimurium can efficiently kill these professional phagocytes via a mechanism that is dependent on sipB and the Salmonella pathogenicity island 1-encoded type III protein secretion system. Rapid phosphatidylserine redistribution, caspase activation, and loss of plasma membrane integrity were characteristic of dendritic cells infected with wild-type Salmonella, but not sipB mutant bacteria. Caspase-1 was particularly important in this process because Salmonella-induced dendritic cell death was dramatically reduced in the presence of a caspase-1-specific inhibitor. Furthermore, dendritic cells obtained from caspase-1-deficient mice, but not heterozygous littermate control mice, were resistant to Salmonella-induced cytotoxicity. We hypothesize that Salmonella have evolved the ability to selectively kill professional APCs to combat, exploit, or evade immune defense mechanisms.
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71
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Johansson C, Wick MJ. Liver Dendritic Cells Present Bacterial Antigens and Produce Cytokines uponSalmonellaEncounter. THE JOURNAL OF IMMUNOLOGY 2004; 172:2496-503. [PMID: 14764722 DOI: 10.4049/jimmunol.172.4.2496] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
The capacity of murine liver dendritic cells (DC) to present bacterial Ags and produce cytokines after encounter with Salmonella was studied. Freshly isolated, nonparenchymal liver CD11c(+) cells had heterogeneous expression of MHC class II and CD11b and a low level of CD40 and CD86 expression. Characterization of liver DC subsets revealed that CD8alpha(-)CD4(-) double negative cells constituted the majority of liver CD11c(+) ( approximately 85%) with few cells expressing CD8alpha or CD4. Flow cytometry analysis of freshly isolated CD11c(+) cells enriched from the liver and cocultured with Salmonella expressing green fluorescent protein (GFP) showed that CD11c(+) MHC class II(high) cells had a greater capacity to internalize Salmonella relative to CD11c(+) MHC class II(low) cells. Moreover, both CD8alpha(-) and CD8alpha(+) liver DC internalized bacteria with similar efficiency after both in vitro and in vivo infection. CD11c(+) cells enriched from the liver could also process Salmonella for peptide presentation on MHC class I and class II to primary, Ag-specific T cells after internalization requiring actin cytoskeletal rearrangements. Flow cytometry analysis of liver CD11c(+) cells infected with Salmonella expressing GFP showed that both CD8alpha(-) and CD8alpha(+) DC produced IL-12p40 and TNF-alpha. The majority of cytokine-positive cells did not contain bacteria (GFP(-)) whereas only a minor fraction of cytokine-positive cells were GFP(+). Furthermore, only approximately 30-50% of liver DC containing bacteria (GFP(+)) produced cytokines. Thus, liver DC can internalize and process Salmonella for peptide presentation to CD4(+) and CD8(+) T cells and elicit proinflammatory cytokine production upon Salmonella encounter, suggesting that DC in the liver may contribute to immunity against hepatotropic bacteria.
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Affiliation(s)
- Cecilia Johansson
- Department of Cell and Molecular Biology, Section for Immunology, Lund University, Lund, Sweden
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72
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Abstract
Dendritic cells (DC) are the key link between innate and adaptive immunity. Features of DC, including their presence at sites of antigen entry, their ability to migrate from peripheral sites to secondary lymphoid organs, and their superior capacity to stimulate naïve T cells places them in this pivotal role in the immune system. DC also produce cytokines, particularly IL-12, upon antigen encounter and can thus influence the ensuing adaptive immune response. As DC are phagocytic antigen-presenting cells located at sites exposed to bacterial invaders, studies have been performed to gain insight into the role of DC in combating bacterial infections. Indeed, studies with Salmonella have shown that DC can internalize and process this bacterium for peptide presentation on MHC-II as well as MHC-I. DC can also act as bystander antigen--presenting cells by presenting Salmonella antigens after internalizing neighbouring cells that have undergone Salmonella-induced apoptotic death. DC also produce IL-12 and TNF-alpha upon Salmonella encounter. Moreover, studies in a murine infection model have shown that splenic DC increase surface expression of co-stimulatory molecules during infection, and DC contain intracellular bacteria. In addition, quantitative changes occur in splenic DC numbers in the early stages of oral Salmonella infection, and this is accompanied by redistribution of the defined DC subsets in the spleen of infected mice. DC from Salmonella-infected mice also produce cytokines and can stimulate bacteria-specific T cells upon ex vivo co-culture. In addition, DC may play a role in the traversal of bacteria from the intestinal lumen. Studying the function of DC during Salmonella infection provides insight into the capacity of this sophisticated antigen-presenting cell to initiate and modulate the immune response to bacteria.
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Affiliation(s)
- Malin Sundquist
- Department of Clinical Immunology, Göteborg University, Göteborg, Sweden
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73
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Vassiliou E, Jing H, Ganea D. Prostaglandin E2 inhibits TNF production in murine bone marrow-derived dendritic cells. Cell Immunol 2003; 223:120-32. [PMID: 14527510 DOI: 10.1016/s0008-8749(03)00158-8] [Citation(s) in RCA: 97] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Exposure to pathogens induces dendritic cells to release inflammatory cytokines and chemokines. The inflammatory response is controlled by endogenous agents such as anti-inflammatory cytokines, glucocorticoids, anti-inflammatory neuropeptides, and lipid mediators. This study is the first report on the inhibition by prostaglandin E2 (PGE2) of TNF release from bone marrow-derived dendritic cells stimulated with lipopolysaccharide (LPS), a TLR4 ligand, or peptidoglycan, a TLR2 ligand. The inhibition of TNF occurs at both mRNA and protein level. The inhibitory effect of PGE2 is mediated by the EP2 and EP4 receptors, and involves both PKA signaling and mediation by DC-derived IL-10. Intraperitoneal administration of PGE2 together with LPS results in a reduction in serum TNF and intracellular TNF in peritoneal exudate cells, compared to LPS alone. In addition, administration of PGE2 in vivo reduces the numbers of CD11c+ DCc that accumulate in the peritoneal cavity in response to LPS. The various implications of the PGE2-induced reduction in TNF are discussed.
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Affiliation(s)
- Evros Vassiliou
- Department of Biological Sciences, Rutgers University, 101 Warren St, Newark, NJ 07102, USA
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74
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Jantsch J, Cheminay C, Chakravortty D, Lindig T, Hein J, Hensel M. Intracellular activities of Salmonella enterica in murine dendritic cells. Cell Microbiol 2003; 5:933-45. [PMID: 14641178 DOI: 10.1046/j.1462-5822.2003.00334.x] [Citation(s) in RCA: 67] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
Dendritic cells (DC) efficiently phagocytose invading bacteria, but fail to kill intracellular pathogens such as Salmonella enterica serovar Typhimurium (S. Typhimurium). We analysed the intracellular fate of Salmonella in murine bone marrow-derived DC (BM-DC). The intracellular proliferation and subcellular localization were investigated for wild-type S. Typhimurium and mutants deficient in Salmonella pathogenicity island 2 (SPI2), a complex virulence factor that is essential for systemic infections in the murine model and intracellular survival and replication in macrophages. Using a segregative plasmid to monitor intracellular cell division, we observed that, in BM-DC, S. Typhimurium represents a static, non-dividing population. In BM-DC, S. Typhimurium resides in a membrane-bound compartment that has acquired late endosomal markers. However, these bacteria respond to intracellular stimuli, because induction of SPI2 genes was observed. S. Typhimurium within DC are also able to translocate a virulence protein into their host cells. SPI2 function was not required for intracellular survival in DC, but we observed that the maturation of the Salmonella-containing vesicle is different in DC infected with wild-type bacteria and a strain deficient in SPI2. Our observations indicate that S. Typhimurium in DC are able to modify normal processes of their host cells.
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Affiliation(s)
- Jonathan Jantsch
- Institut für Klinische Mikrobiologie, Immunologie und Hygiene, FAU Erlangen-Nürnberg, Wasserturmstrasse 3-5, D-91054 Erlangen, Germany
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75
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Wilson NS, El-Sukkari D, Belz GT, Smith CM, Steptoe RJ, Heath WR, Shortman K, Villadangos JA. Most lymphoid organ dendritic cell types are phenotypically and functionally immature. Blood 2003; 102:2187-94. [PMID: 12791652 DOI: 10.1182/blood-2003-02-0513] [Citation(s) in RCA: 261] [Impact Index Per Article: 12.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Dendritic cells (DCs) have been thought to follow a life history, typified by Langerhans cells (LCs), with 2 major developmental stages: an immature stage that captures antigens in the periphery and a mature stage that presents those antigens in the lymphoid organs. However, a systematic assessment of the maturity of lymphoid organ DCs has been lacking. We have analyzed the maturity of the DC types found in the steady state in the spleen, lymph nodes (LNs), and thymus. The DCs that migrate into the iliac, mesenteric, mediastinal, or subcutaneous LNs from peripheral tissues were mature and therefore could not process and present newly encountered antigens. However, all the other DC types were phenotypically and functionally immature: they expressed low levels of surface major histocompatibility complex class II (MHC II) and CD86, accumulated MHC II in their endosomes, and could present newly encountered antigens. These immature DCs could be induced to mature by culture in vitro or by inoculation of inflammatory stimuli in vivo. Therefore, the lymphoid organs contain a large cohort of immature DCs, most likely for the maintenance of peripheral tolerance, which can respond to infections reaching those organs and mature in situ.
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Affiliation(s)
- Nicholas S Wilson
- Immunology Division, The Walter and Eliza Hall Institute of Medical Research, 1G Royal Parade, Melbourne, Victoria 3050, Australia
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76
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Abstract
Dendritic cells are bone marrow-derived professional antigen presenting cells that play major roles in both the induction of primary immune responses and tolerance. It has become clear that dendritic cells are a heterogeneous group of cells that vary in cell surface marker expression and function. Multiple dendritic cell subsets have now been defined in mouse lymphoid organs and peripheral tissues. A knowledge of the function and relationship between dendritic cell subsets will be essential for understanding the regulation of immune homeostasis, immune responses and tolerance. While an increasing number of dendritic cell progenitors are being identified, the pathways that connect them remain unclear. In addition, it is unclear whether the functional divisions reflect maturation status, subset specialization or functional plasticity in response to specific pathogen and environmental signals. This review summarizes the current knowledge about the function and lineage relationship of dendritic cell subsets. It also discusses some of the difficulties associated with dendritic cell subset analysis.
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Affiliation(s)
- Heather L Wilson
- School of Biochemistry and Molecular Biology, Australian National University, Canberra, Australian Capital Territory 0200, Australia
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77
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Abstract
Although the presentation of peptide-major histocompatibility complex class II (pMHC class II) complexes to CD4 T cells has been studied extensively in vitro, knowledge of this process in vivo is limited. Unlike the in vitro situation, antigen presentation in vivo takes place within a complex microenvironment in which the movements of antigens, antigen-presenting cells (APCs) and T cells are governed by anatomic constraints. Here we review developments in the areas of lymph node architecture, APC subsets and T cell activation that have shed light on how antigen presentation occurs in the lymph nodes.
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Affiliation(s)
- Andrea A Itano
- Department of Microbiology and the Center for Immunology, University of Minnesota, MMC 334, 420 Delaware St. SE, Minneapolis, Minnesota 55455, USA
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78
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Abstract
Host defence against infection requires an integrated response of both the innate and adaptive arms of the immune system. Emerging data indicate that dendritic cells contribute an essential part to the initiation and regulation of adaptive immunity. Dendritic cells guard the sites of pathogen entry to the host and are uniquely suited to detect and capture invading microbes. Upon recognition of microbial structures and appropriate activation, a maturation programme is triggered and dendritic cells migrate to lymphoid organs to stimulate a primary cell-mediated immune response. Moreover, dendritic cells play a critical role in shaping the emerging response, thereby controlling the course of infection. They can discriminate between various types of microorganisms and are capable of producing different cytokines in response to different microbial stimuli. On the other hand, pathogens developed numerous strategies to evade and subvert dendritic cell functions. Elucidating the interactions of dendritic cells with microbial pathogens may lead to novel strategies for combating infectious diseases by dendritic cell-based vaccination and immunotherapy. This review highlights recent advances in our knowledge of the unique role of dendritic cells in counteracting microbial infections.
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Affiliation(s)
- Heidrun Moll
- Institute for Molecular Biology of Infectious Diseases, University of Würzburg, Germany.
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79
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Edwards AD, Chaussabel D, Tomlinson S, Schulz O, Sher A, Reis e Sousa C. Relationships among murine CD11c(high) dendritic cell subsets as revealed by baseline gene expression patterns. JOURNAL OF IMMUNOLOGY (BALTIMORE, MD. : 1950) 2003; 171:47-60. [PMID: 12816982 DOI: 10.4049/jimmunol.171.1.47] [Citation(s) in RCA: 107] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
The functional relationships and properties of different subtypes of dendritic cells (DC) remain largely undefined. To better characterize these cells, we used global gene analysis to determine gene expression patterns among murine CD11c(high) DC subsets. CD4(+), CD8alpha(+), and CD8alpha(-) CD4(-) (double negative (DN)) DC were purified from spleens of normal C57/BL6 mice and analyzed using Affymetrix microarrays. The CD4(+) and CD8alpha(+) DC subsets showed distinct basal expression profiles differing by >200 individual genes. These included known DC subset markers as well as previously unrecognized, differentially expressed CD Ags such as CD1d, CD5, CD22, and CD72. Flow cytometric analysis confirmed differential expression in nine of nine cases, thereby validating the microarray analysis. Interestingly, the microarray expression profiles for DN cells strongly resembled those of CD4(+) DC, differing from them by <25 genes. This suggests that CD4(+) and DN DC are closely related phylogenetically, whereas CD8alpha(+) DC represent a more distant lineage, supporting the historical distinction between CD8alpha(+) and CD8alpha(-) DC. However, staining patterns revealed that in contrast to CD4(+) DC, the DN subset is heterogeneous and comprises at least two subpopulations. Gene Ontology and literature mining analyses of genes expressed differentially among DC subsets indicated strong associations with immune response parameters as well as cell differentiation and signaling. Such associations offer clues to possible unique functions of the CD11c(high) DC subsets that to date have been difficult to define as rigid distinctions.
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Affiliation(s)
- Alexander D Edwards
- Immunobiology Laboratory and Computational Genome Analysis Laboratory, Cancer Research UK, London Research Institute, London, UK
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80
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Westerberg L, Wallin RPA, Greicius G, Ljunggren HG, Severinson E. Efficient antigen presentation of soluble, but not particulate, antigen in the absence of Wiskott-Aldrich syndrome protein. Immunology 2003; 109:384-91. [PMID: 12807484 PMCID: PMC1782978 DOI: 10.1046/j.1365-2567.2003.01668.x] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
B cells and dendritic cells, lacking functional Wiskott-Aldrich syndrome protein (WASP), have aberrant formation of membrane protrusions. We hypothesized that protrusions may play a role in antigen presentation, and consequently, that impaired antigen presentation may be an underlying factor of the immune deficiency in patients with Wiskott-Aldrich syndrome. In this paper, we investigated the antigen presentation capacity of B cells and dendritic cells from WASP knockout mice, using soluble and particulate antigen, to CD4+ T cells from T-cell receptor transgenic DO11.10 mice. As antigen we used soluble ovalbumin (OVA), a peptide thereof (amino acids 323-339) or bacteria expressing OVA. We found that WASP-deficient B cells and dendritic cells efficiently processed and presented soluble OVA protein as well as its peptide in vitro, inducing proliferation and cytokine production from CD4+ T cells. Antigen presentation of soluble protein was efficient also in vivo, because immunization of WASP-deficient mice with OVA elicited proliferation of transferred, fluorescent-labelled, CD4+ T cells. Although we could detect uptake of bacteria in dendritic cells, processing and presentation of bacterial-expressed OVA was impaired in WASP-deficient dendritic cells. In conclusion, our data suggest that WASP is not needed for processing and presentation of soluble antigen, but that efficient presentation of particulate antigen require WASP.
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Affiliation(s)
- Lisa Westerberg
- Department of Cell and Molecular Biology, Karolinska Institutet, Stockholm, Sweden.
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81
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Abstract
Models of infection have provided important insight into the function of dendritic cells (DC) in vivo. Several microbial products induce DC maturation via Toll-like receptors, a process that is crucial for the ability of DC to initiate adaptive immune responses. Splenic DC have also been shown to produce IL-12 during infection in vivo. This DC-derived IL-12 might be important to skew T cell responses towards Th1. Microbial infections also induce changes in the DC populations of lymphoid organs, often in a subset-specific manner, manifested as an accumulation and redistribution of DC. Furthermore, data are emerging pointing at an absolute requirement of DC in priming of naïve T cells in vivo.
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Affiliation(s)
- Malin Sundquist
- Department of Clinical Immunology, Göteborg University, Sweden
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82
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Harding CV, Ramachandra L, Wick MJ. Interaction of bacteria with antigen presenting cells: influences on antigen presentation and antibacterial immunity. Curr Opin Immunol 2003; 15:112-9. [PMID: 12495742 DOI: 10.1016/s0952-7915(02)00008-0] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Affiliation(s)
- Clifford V Harding
- Department of Pathology, Case Western Reserve University, 10900 Euclid Avenue, Cleveland, OH 44106-4943, USA
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83
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Abstract
Dendritic cells (DC) are an important link between the innate and adaptive immune response and are key antigen presenting cells in triggering specific immunity. This review summarizes the role of DC and the DC subsets during infection with the facultative intracellular bacterium Salmonella. The capacity of DC to stimulate Salmonella-specific T cells by direct and indirect presentation of Salmonella antigens as well as the cytokine production capacity of DC upon Salmonella encounter are discussed. In addition, changes in the number, localization and cytokine production by splenic DC subsets during infection are reviewed. Studying the function of DC during Salmonella infection provides insight into the capacity of this phagocytic antigen presenting cell to initiate and modulate an immune response during bacterial infection.
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Affiliation(s)
- Mary Jo Wick
- Department of Clinical Immunology, University of Göteborg, Guldhedsgatan 10, SE-413 46, Göteborg, Sweden.
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84
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Pasetti MF, Levine MM, Sztein MB. Animal models paving the way for clinical trials of attenuated Salmonella enterica serovar Typhi live oral vaccines and live vectors. Vaccine 2003; 21:401-18. [PMID: 12531639 DOI: 10.1016/s0264-410x(02)00472-3] [Citation(s) in RCA: 82] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Attenuated Salmonella enterica serovar Typhi (S. Typhi) strains can serve as safe and effective oral vaccines to prevent typhoid fever and as live vectors to deliver foreign antigens to the immune system, either by the bacteria expressing antigens through prokaryotic expression plasmids or by delivering foreign genes carried on eukaryotic expression systems (DNA vaccines). The practical utility of such live vector vaccines relies on achieving a proper balance between minimizing the vaccine's reactogenicity and maximizing its immunogenicity. To advance to clinical trials, vaccine candidates need to be pre-clinically evaluated in relevant animal models that attempt to predict what their safety and immunogenicity profile will be when administered to humans. Since S. Typhi is a human-restricted pathogen, a major obstacle that has impeded the progress of vaccine development has been the shortcomings of the animal models available to assess vaccine candidates. In this review, we summarize the usefulness of animal models in the assessment of the degree of attenuation and immunogenicity of novel attenuated S. Typhi strains as vaccine candidates for the prevention of typhoid fever and as live vectors in humans.
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Affiliation(s)
- Marcela F Pasetti
- Center for Vaccine Development, University of Maryland School of Medicine, Room 480, 685 West Baltimore Street, Baltimore, MD 21201, USA.
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85
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Schulz O, Reis e Sousa C. Cross-presentation of cell-associated antigens by CD8alpha+ dendritic cells is attributable to their ability to internalize dead cells. Immunology 2002; 107:183-9. [PMID: 12383197 PMCID: PMC1782783 DOI: 10.1046/j.1365-2567.2002.01513.x] [Citation(s) in RCA: 167] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
In the mouse, cross-presentation is an exclusive property of the CD8alpha+ subset of dendritic cells (DC) but the basis for this selectivity remains unclear. Here we report that splenic CD8alpha+ DC are much superior to other DC subsets in internalizing dying cells in vitro. In contrast, CD8alpha+, CD8alpha- CD4+ and CD8alpha- CD4- DC subsets phagocytose bacteria or latex beads to a similar extent. Although CD8alpha+ DC are better than CD4+ DC at presenting ovalbumin (OVA)-loaded splenocytes to naïve OT-I T lymphocytes, CD4+ DC are better at presenting OVA-expressing Escherichia coli to the same T cells. In both cases, presentation is abrogated by lactacystin. These results show that both splenic CD8alpha+ and CD8alpha- DC can present exogenous antigens on major histocompatibility complex (MHC) class I via a proteasome-dependent pathway and suggest that the specialized cross-presenting function of CD8alpha+ DC is a result of their ability to endocytose dying cells rather than a unique pathway for handling endosomal contents.
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Affiliation(s)
- Oliver Schulz
- Immunobiology Laboratory, Cancer Research UK, London Research Institute, Lincoln's Inn Fields Laboratories, 44 Lincoln's Inn Fields, London WC2A 3PX, UK
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86
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Abstract
One type of phagocytic antigen-presenting cell (APC) - the dendritic cell (DC) - may have specialized functions during infection with the bacterium Salmonella, including a possible role in transporting Salmonella across the intestinal barrier. In addition, changes in the number, localization and cytokine production of CD8alpha+, CD8alpha-CD4+ and CD8alpha-CD4- DC subsets occur during infection. DCs function in stimulating bacteria-specific T cells by direct presentation of Salmonella antigens and as bystander APCs. Studying the function of DCs during Salmonella infection provides insight into the capacity of these sophisticated APCs, which are a key link between innate and adaptive immunity, to initiate and modulate the immune response to a bacterial infection.
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Affiliation(s)
- Mary Jo Wick
- Department of Clinical Immunology, University of Göteborg, Guldhedsgatan 10, Göteborg, Sweden.
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