51
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Parsa S, Pfeifer B. Engineering bacterial vectors for delivery of genes and proteins to antigen-presenting cells. Mol Pharm 2007; 4:4-17. [PMID: 17233543 DOI: 10.1021/mp0600889] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Bacterial vectors offer a biological route to gene and protein delivery with this article featuring delivery to antigen-presenting cells (APCs). Primarily in the context of immune stimulation against infectious disease or cancer, the goal of bacterially mediated delivery is to overcome the hurdles to effective macromolecule delivery. This review will present several bacterial vectors as macromolecule (protein or gene) delivery devices with both innate and acquirable (or engineered) biological features to facilitate delivery to APCs. The review will also present topics related to large-scale manufacture, storage, and distribution that must be considered if the bacterial delivery devices are ever to be used in a global market.
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Affiliation(s)
- Saba Parsa
- Department of Chemical and Biological Engineering, Tufts University, Medford, Massachusetts 02155, USA
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52
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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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53
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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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54
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Raine T, Zaccone P, Mastroeni P, Cooke A. Salmonella typhimurium infection in nonobese diabetic mice generates immunomodulatory dendritic cells able to prevent type 1 diabetes. THE JOURNAL OF IMMUNOLOGY 2006; 177:2224-33. [PMID: 16887982 DOI: 10.4049/jimmunol.177.4.2224] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Infection, commencing across a wide age range, with a live, attenuated strain of Salmonella typhimurium, will halt the development of type 1 diabetes in the NOD mouse. The protective mechanism appears to involve the regulation of autoreactive T cells in a manner associated with long lasting changes in the innate immune compartment of these mice. We show in this study that autoreactive T cell priming and trafficking are altered in mice that have been infected previously by S. typhimurium. These changes are associated with sustained alterations in patterns of chemokine expression. We find that small numbers of dendritic cells from mice that have been previously infected with, but cleared all trace of a S. typhimurium infection are able to prevent the development of diabetes in the highly synchronized and aggressive cyclophosphamide-induced model. The effects we observe on autoreactive T cell trafficking are recapitulated by the immunomodulatory dendritic cell transfers in the cyclophosphamide model.
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Affiliation(s)
- Tim Raine
- Department of Pathology, University of Cambridge, Tennis Court Road, Cambridge, United Kingdom
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55
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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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56
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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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57
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Tam MA, Wick MJ. Differential expansion, activation and effector functions of conventional and plasmacytoid dendritic cells in mouse tissues transiently infected with Listeria monocytogenes. Cell Microbiol 2006; 8:1172-87. [PMID: 16819969 DOI: 10.1111/j.1462-5822.2006.00700.x] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
Dendritic cells (DC) are crucial in generating immunity to infection. Here we characterize changes in DC in terms of number, activation and effector functions, focusing on conventional DC (cDC) and plasmacytoid DC (pDC), in Listeria-infected mice. Kinetic studies showed a subset- and tissue-specific expansion of cDC and upregulation of CD80 and CD86 on splenic and mesenteric lymph node (MLN) cDC after intragastric infection. Expansion of pDC was more prolonged than cDC, and pDC upregulated CD86 and MHC-II, but not CD80, in both the spleen and MLN. cDC were an important source of IL-12 but not TNF-alpha during infection, while pDC made neither of these cytokines. Instead other CD11c(int) cells produced these cytokines. Using five-colour flow cytometry and double intracellular cytokine staining, we detected phenotypically similar CD11c(int)CD11b(+)Gr1(+) cells with distinct capacities to produce TNF-alpha/IL-12 or TNF-alpha/iNOS (inducible nitric oxide synthase) in Listeria-infected tissues. IL-12p70 was also produced by sorted CD11c(hi) and CD11c(int)CD11b(+)Gr1(+) cells. Furthermore, production of TNF-alpha, iNOS and IL-12 was differentially dependent on cellular localization of the bacteria. Cytosol-restricted bacteria induced TNF-alpha and iNOS-producing cells, albeit at lower frequency than wild-type bacteria. In contrast, IL-12 was induced only with wild-type bacteria. These data provide new insight into the relative abundance and function of distinct CD11c-expressing populations during the early stage of Listeria infection.
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Affiliation(s)
- Miguel A Tam
- Department of Clinical Immunology, Göteborg University, Göteborg, Sweden
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58
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Becker M, Cotena A, Gordon S, Platt N. Expression of the class A macrophage scavenger receptor on specific subpopulations of murine dendritic cells limits their endotoxin response. Eur J Immunol 2006; 36:950-60. [PMID: 16552714 DOI: 10.1002/eji.200535660] [Citation(s) in RCA: 56] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
Dendritic cells (DC) function at the interface of innate and acquired immunity and are uniquely sensitive to specific stimuli. Pattern recognition receptors (PRR) on these cells are critically important because of their ability to recognise and initiate responses to conserved microbial-associated molecular signatures. With the exception of Toll-like receptors (TLR), we know relatively little about the specific distribution of other PRR amongst populations of DC. Here, we describe the expression of the murine class A macrophage scavenger receptor (SR-A) and show that it is restricted to specific subpopulations of bone marrow-derived and splenic DC. Importantly, we demonstrate that the receptor significantly alters the response of DC to endotoxin. In contrast to the activities of other PRR that have so far been examined, uniquely SR-A limits the maturation response; SR-A-/- cells display enhanced CD40 expression and TNF-alpha production. We discuss the potential contributions of SR-A to DC biology in the context of the known multiple activities of this receptor.
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Affiliation(s)
- Mike Becker
- Sir William Dunn School of Pathology, University of Oxford, Oxford, UK
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59
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Bertholet S, Debrabant A, Afrin F, Caler E, Mendez S, Tabbara KS, Belkaid Y, Sacks DL. Antigen requirements for efficient priming of CD8+ T cells by Leishmania major-infected dendritic cells. Infect Immun 2005; 73:6620-8. [PMID: 16177338 PMCID: PMC1230980 DOI: 10.1128/iai.73.10.6620-6628.2005] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
CD4(+) and CD8(+) T-cell responses have been shown to be critical for the development and maintenance of acquired resistance to infections with the protozoan parasite Leishmania major. Monitoring the development of immunodominant or clonally restricted T-cell subsets in response to infection has been difficult, however, due to the paucity of known epitopes. We have analyzed the potential of L. major transgenic parasites, expressing the model antigen ovalbumin (OVA), to be presented by antigen-presenting cells to OVA-specific OT-II CD4(+) or OT-I CD8(+) T cells. Truncated OVA was expressed in L. major as part of a secreted or nonsecreted chimeric protein with L. donovani 3' nucleotidase (NT-OVA). Dendritic cells (DC) but not macrophages infected with L. major that secreted NT-OVA could prime OT-I T cells to proliferate and release gamma interferon. A diminished T-cell response was observed when DC were infected with parasites expressing nonsecreted NT-OVA or with heat-killed parasites. Inoculation of mice with transgenic parasites elicited the proliferation of adoptively transferred OT-I T cells and their recruitment to the site of infection in the skin. Together, these results demonstrate the possibility of targeting heterologous antigens to specific cellular compartments in L. major and suggest that proteins secreted or released by L. major in infected DC are a major source of peptides for the generation of parasite-specific CD8(+) T cells. The ability of L. major transgenic parasites to activate OT-I CD8(+) T cells in vivo will permit the analysis of parasite-driven T-cell expansion, differentiation, and recruitment at the clonal level.
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Affiliation(s)
- Sylvie Bertholet
- Laboratory of Parasitic Diseases, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland 20892, USA
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60
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Tierrez A, García-del Portillo F. New concepts in Salmonella virulence: the importance of reducing the intracellular growth rate in the host. Cell Microbiol 2005; 7:901-9. [PMID: 15953023 DOI: 10.1111/j.1462-5822.2005.00540.x] [Citation(s) in RCA: 59] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
The literature refers to Salmonella enterica as an intracellular bacterial pathogen that proliferates within vacuoles of mammalian cells. However, recent in vivo studies have revealed that the vast majority of infected cells contain very few intracellular bacteria (three to four organisms). Salmonella intracellular growth is also limited in cultured dendritic cells and fibroblasts, two cell types abundant in tissues located underneath the intestinal epithelium. Recently, a Salmonella factor previously known for its role as a negative regulator of intracellular growth has been shown to tightly repress certain pathogen functions upon host colonization and to be critical for virulence. The connection between virulence and the negative control of intracellular growth is further sustained by the fact that some attenuated mutants overgrow in non-phagocytic cells located in the intestinal lamina propria. These findings are changing our classical view of Salmonella as a fast growing intracellular pathogen and suggest that this pathogen may trigger responses directed to reduce the growth rate within the infected cell. These responses could play a critical role in modulating the delicate balance between disease and persistence.
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Affiliation(s)
- Alberto Tierrez
- Departamento de Biotecnología Microbiana, Centro Nacional de Biotecnología-Consejo Superior de Investigaciones Científicas (CSIC), Darwin 3, 28049 Madrid, Spain
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61
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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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62
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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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63
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Pepper M, Dzierszinski F, Crawford A, Hunter CA, Roos D. Development of a system to study CD4+-T-cell responses to transgenic ovalbumin-expressing Toxoplasma gondii during toxoplasmosis. Infect Immun 2004; 72:7240-6. [PMID: 15557649 PMCID: PMC529136 DOI: 10.1128/iai.72.12.7240-7246.2004] [Citation(s) in RCA: 55] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The study of the immune response to Toxoplasma gondii has provided numerous insights into the role of T cells in resistance to intracellular infections. However, the complexity of this eukaryote pathogen has made it difficult to characterize immunodominant epitopes that would allow the identification of T cells with a known specificity for parasite antigens. As a consequence, analysis of T-cell responses to T. gondii has been based on characterization of the percentage of T cells that express an activated phenotype during infection and on the ability of these cells to produce cytokines in response to complex mixtures of parasite antigens. In order to study specific CD4(+) T cells responses to T. gondii, recombinant parasites that express a truncated ovalbumin (OVA) protein, in either a cytosolic or a secreted form, were engineered. In vitro and in vivo studies reveal that transgenic parasites expressing secreted OVA are able to stimulate T-cell receptor-transgenic OVA-specific CD4(+) T cells to proliferate, express an activated phenotype, and produce gamma interferon (IFN-gamma). Furthermore, the adoptive transfer of OVA-specific T cells into IFN-gamma(-/-) mice provided enhanced protection against infection with the OVA-transgenic (but not parental) parasites. Together, these studies establish the utility of this transgenic system to study CD4(+)-T-cell responses during toxoplasmosis.
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Affiliation(s)
- Marion Pepper
- Department of Biology, University of Pennsylvania, Philadelphia, PA 19104, USA
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64
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Zaccone P, Raine T, Sidobre S, Kronenberg M, Mastroeni P, Cooke A. Salmonella typhimurium infection halts development of type 1 diabetes in NOD mice. Eur J Immunol 2004; 34:3246-56. [PMID: 15376194 DOI: 10.1002/eji.200425285] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
Infectious disease has been proposed as an environmental modifier of autoimmunity in both human populations and the NOD mouse. We found that infection of NOD mice with attenuated, but not killed, Salmonella typhimurium can reduce the incidence of type 1 diabetes (T1D), even if infection occurs after the development of a peri-islet pancreatic infiltrate. Functional diabetogenic effector T cells are still present, as demonstrated by the initiation of diabetes in NOD-scid recipients of transferred splenocytes. High levels of IFN-gamma are secreted by splenocytes of infected mice, but there is no evidence of involvement of IL-10 in the protective effect of the infection. Finally, prolonged changes in cell subsets are observed in infected mice involving invariant Valpha14Jalpha281 NuKappaTau and dendritic cells. These data reinforce the idea that prevention of T1D in the NOD mouse cannot be reduced to the simple Th1/Th2 paradigm and that different infections may involve different protective mechanisms.
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Affiliation(s)
- Paola Zaccone
- Immunology Division, Department of Pathology, University of Cambridge, Cambridge, UK
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65
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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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66
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Srinivasan A, Foley J, Ravindran R, McSorley SJ. Low-dose Salmonella infection evades activation of flagellin-specific CD4 T cells. THE JOURNAL OF IMMUNOLOGY 2004; 173:4091-9. [PMID: 15356159 DOI: 10.4049/jimmunol.173.6.4091] [Citation(s) in RCA: 54] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Many pathogens can establish a lethal infection from relatively small inocula, yet the effect of infectious dose upon CD4 T cell activation is not clearly understood. This issue was examined by tracking Salmonella flagellin-specific SM1 T cells in vivo, after i.v. and oral challenge of mice with virulent Salmonella typhimurium. SM1 T cells rapidly expressed activation markers and expanded in response to high-dose infection but remained completely unresponsive in mice challenged with low doses of Salmonella. SM1 T cells, in these mice, remained unresponsive, despite massive bacterial replication in vivo. Naive SM1 T cells in low-dose Salmonella-infected mice were activated rapidly after the injection of flagellin peptide, demonstrating that these T cells were fully capable of responding, ruling out the possibility of a bacterial-induced suppressive environment. The inability of flagellin-specific SM1 T cells to respond to low-dose infection was not due to Ag down-regulation, because flagellin expression was detected using a functional assay. Together, these data suggest that low-dose Salmonella infection can evade flagellin-specific CD4 T cell activation in vivo.
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Affiliation(s)
- Aparna Srinivasan
- Department of Medicine, Division of Immunology, University of Connecticut Health Center, Farmington, CT 06030, USA
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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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Cooke A, Zaccone P, Raine T, Phillips JM, Dunne DW. Infection and autoimmunity: are we winning the war, only to lose the peace? Trends Parasitol 2004; 20:316-21. [PMID: 15193562 DOI: 10.1016/j.pt.2004.04.010] [Citation(s) in RCA: 59] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
Affiliation(s)
- Anne Cooke
- Pathology Department, University of Cambridge, Tennis Court Road, Cambridge CB2 1QP, UK.
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69
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Leisewitz AL, Rockett KA, Gumede B, Jones M, Urban B, Kwiatkowski DP. Response of the splenic dendritic cell population to malaria infection. Infect Immun 2004; 72:4233-9. [PMID: 15213168 PMCID: PMC427429 DOI: 10.1128/iai.72.7.4233-4239.2004] [Citation(s) in RCA: 60] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Dendritic cells, particularly those residing in the spleen, are thought to orchestrate acquired immunity to malaria, but it is not known how the splenic dendritic cell population responds to malaria infection and how this response compares with the responses of other antigen-presenting cells. We investigated this question for Plasmodium chabaudi AS infection in C57BL/6 mice. We found that dendritic cells, defined here by the CD11c marker, migrated from the marginal zone of the spleen into the CD4(+) T-cell area within 5 days after parasites entered the bloodstream. This contrasted with the results observed for the macrophage and B-cell populations, which expanded greatly but did not show any comparable migration. Over the same time period dendritic cells showed upregulation of CD40, CD54, and CD86 costimulatory molecules that are required for successful T-cell activation. In dendritic cells, the peak intracellular gamma interferon expression (as shown by fluorescence-activated cell sorting) was on day 5, 2 days earlier than the peak expression in B-cells or macrophages. These findings show that splenic dendritic cells are actively engaged in the earliest phase of malarial infection in vivo and are likely to be critical in shaping the subsequent immune response.
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Affiliation(s)
- Andrew L Leisewitz
- Weatherall Institute of of Molecular Medicine, and University Department of Paediatrics, John Radcliffe Hospital, University of Oxford, Oxford, UK.
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70
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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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71
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Mastroeni P, Sheppard M. Salmonella infections in the mouse model: host resistance factors and in vivo dynamics of bacterial spread and distribution in the tissues. Microbes Infect 2004; 6:398-405. [PMID: 15101397 DOI: 10.1016/j.micinf.2003.12.009] [Citation(s) in RCA: 70] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
The mouse model is widely used to study the mechanisms of the pathogenesis of, and immunity to, systemic salmonellosis. During infection, Salmonella grows in phagocytic cells that reside in well-defined pathological lesions, are activated by cytokines and control the growth of intracellular bacteria using oxygen and nitrogen derivatives. Salmonella growth in the tissues results in the spatial segregation of bacterial populations and in their continuous distribution to new phagocytes. High bacterial numbers within infected phagocytes are uncommon in vivo.
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Affiliation(s)
- Pietro Mastroeni
- Centre for Veterinary Science, University of Cambridge, Madingley Road, Cambridge CB3 OES, UK.
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72
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De Trez C, Brait M, Leo O, Aebischer T, Torrentera FA, Carlier Y, Muraille E. Myd88-dependent in vivo maturation of splenic dendritic cells induced by Leishmania donovani and other Leishmania species. Infect Immun 2004; 72:824-32. [PMID: 14742526 PMCID: PMC321621 DOI: 10.1128/iai.72.2.824-832.2004] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The usual agent of visceral leishmaniasis in the Old World is Leishmania donovani, which typically produces systemic diseases in humans and mice. L. donovani has developed efficient strategies to infect and persist in macrophages from spleen and liver. Dendritic cells (DC) are sentinels of the immune system. Following recognition of evolutionary conserved microbial products, DC undergo a maturation process and activate antigen-specific naïve T cells. In the present report we provide new insights into how DC detect Leishmania in vivo. We demonstrate that in both C57BL/6 and BALB/c mice, systemic injection of L. donovani induced the migration of splenic DC from marginal zones to T-cell areas. During migration, DC upregulated the expression of major histocompatibility complex II and costimulatory receptors (such as CD40, CD80, and CD86). Leishmania-induced maturation requires live parasites and is not restricted to L. donovani, as L. braziliensis, L. major, and L. mexicana induced a similar process. Using a green fluorescent protein-expressing parasite, we demonstrate that DC undergoing maturation in vivo display no parasite internalization. We also show that L. donovani-induced DC maturation was partially abolished in MyD88-deficient mice. Taken together, our data suggest that Leishmania-induced DC maturation results from direct recognition of Leishmania by DC, and not from DC infection, and that MyD88-dependent receptors are implicated in this process.
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Affiliation(s)
- Carl De Trez
- Laboratory of Animal Physiology, Institut de Biologie et de Médecine Moléculaire, Université Libre de Bruxelles, Gosselies, Belgium
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73
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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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74
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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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75
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Sheppard M, Webb C, Heath F, Mallows V, Emilianus R, Maskell D, Mastroeni P. Dynamics of bacterial growth and distribution within the liver during Salmonella infection. Cell Microbiol 2003; 5:593-600. [PMID: 12925129 DOI: 10.1046/j.1462-5822.2003.00296.x] [Citation(s) in RCA: 118] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
Salmonella enterica causes severe systemic diseases in humans and animals and grows intracellularly within discrete tissue foci that become pathological lesions. Because of its lifestyle Salmonella is a superb model for studying the in vivo dynamics of bacterial distribution. Using multicolour fluorescence microscopy in the mouse typhoid model we have studied the interaction between different bacterial populations in the same host as well as the dynamic evolution of foci of infection in relation to bacterial growth and localization. We showed that the growth of Salmonella in the liver results in the spread of the microorganisms to new foci of infection rather than simply in the expansion of the initial ones. These foci were associated with independently segregating bacterial populations and with low numbers of bacteria in each infected phagocyte. Using fast-growing and slow-growing bacteria we also showed that the increase in the number of infected phagocytes parallels the net rate of bacterial growth of the microorganisms in the tissues. These findings suggest a novel mechanism underlying growth of salmonellae in vivo with important consequences for understanding mechanisms of resistance and immunity.
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Affiliation(s)
- Mark Sheppard
- Bacterial Infection Group, Centre for Veterinary Science, Department of Clinical Veterinary Medicine, University of Cambridge, Madingley Road, Cambridge CB3 0ES, UK
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76
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Abstract
CD8 T cells respond to viral infections but also participate in defense against bacterial and protozoal infections. In the last few years, as new methods to accurately quantify and characterize pathogen-specific CD8 T cells have become available, our understanding of in vivo T cell responses has increased dramatically. Pathogen-specific T cells, once thought to be quite rare following infection, are now known to be present at very high frequencies, particularly in peripheral, nonlymphoid tissues. With the ability to visualize in vivo CD8 T cell responses has come the recognition that T cell expansion is programmed and, to a great extent, independent of antigen concentrations. Comparison of CD8 T cell responses to different pathogens also highlights the intricate relationship between microbially induced innate inflammatory responses and the kinetics, magnitude, and character of long-term T cell responses. This review describes recent progress in some of the major murine models of CD8 T cell-mediated immunity to viral, bacterial, and protozoal infection.
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Affiliation(s)
- Phillip Wong
- Memorial Sloan-Kettering Cancer Center, 1275 York Avenue, New York, NY 10021, USA.
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77
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Bumann D. T cell receptor-transgenic mouse models for studying cellular immune responses to Salmonella in vivo. FEMS IMMUNOLOGY AND MEDICAL MICROBIOLOGY 2003; 37:105-9. [PMID: 12832113 DOI: 10.1016/s0928-8244(03)00064-6] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
Cellular immune responses are crucial both for protective immunity against salmonellosis, and for the immunogenicity of oral vaccines based on avirulent live Salmonella as antigen carriers. The crucial early steps of T cell induction are difficult to investigate in conventional animals, but recently developed T cell receptor (TCR)-transgenic models allow visualization of antigen-specific T cells in vivo while they become induced. In this review, the results obtained with four different TCR-transgenic Salmonella infection models are described, and advantages and potential limits of each of the different models are compared.
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Affiliation(s)
- Dirk Bumann
- Max-Planck-Institut für Infektionsbiologie, Abteilung Molekulare Biologie, Schumannstrasse 21/22, 10117 Berlin, Germany.
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78
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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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79
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Abstract
Salmonella enterica serovar Typhi (S. typhi) causes human typhoid fever, a serious and widespread disease in developing countries. Other Salmonella serovars are associated with food-borne infections. The recent emergence of multi-drug-resistant Salmonella strains highlights the need for better preventive measures, including vaccination. The available vaccines against Salmonella infection do not confer optimal protection. The design of new Salmonella vaccines must be based on the identification of suitable virulence genes and on knowledge of the immunological mechanisms of resistance to the disease. Control and clearance of a vaccine strain rely on the phagocyte oxidative burst, reactive nitrogen intermediates, inflammatory cytokines and CD4(+) TCR-alphabeta(+) T cells and are controlled by genes including NRAMP1 and MHC class II. Vaccine-induced resistance to reinfection requires the presence of Th1-type immunological memory and anti-Salmonella antibodies. The interaction between T and B cells is essential for the development of resistance following vaccination. The identification of immunodeficiencies that render individuals more susceptible to salmonellosis must be taken into consideration when designing and testing live attenuated Salmonella vaccines. An ideal live Salmonella vaccine should therefore be safe, regardless of the immunological status of the vaccinee, but still immunogenic.
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Affiliation(s)
- Pietro Mastroeni
- Bacterial Infection Group, Centre for Veterinary Science, Department of Clinical Veterinary Medicine, University of Cambridge, Madingley Road, Cambridge CB3 0ES, UK
| | - Nathalie Ménager
- Bacterial Infection Group, Centre for Veterinary Science, Department of Clinical Veterinary Medicine, University of Cambridge, Madingley Road, Cambridge CB3 0ES, UK
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80
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Mixter PF, Klena JD, Flom GA, Siegesmund AM, Konkel ME. In vivo tracking of Campylobacter jejuni by using a novel recombinant expressing green fluorescent protein. Appl Environ Microbiol 2003; 69:2864-74. [PMID: 12732559 PMCID: PMC154531 DOI: 10.1128/aem.69.5.2864-2874.2003] [Citation(s) in RCA: 23] [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
Campylobacter jejuni is a leading cause of food-borne disease in developed countries. The goal of this study was to develop a plasmid-based reporter system with green fluorescent protein (GFP) to facilitate the study of C. jejuni in a variety of niches. C. jejuni transformants harboring the pMEK91 GFP gene (gfp)-containing vector were readily detectable by both fluorescence microscopy and flow cytometry. Given the ease of detecting these organisms, additional experiments were performed in which BALB/c mice were injected intraperitoneally with C. jejuni harboring the gfp-containing vector. Four hours after injection of the mice, flow cytometry analyses determined that C. jejuni synthesizing GFP were predominantly associated with granulocytes. More specifically, the proportion of CD11b(+) Gr-1(+) lavage neutrophils with green fluorescence ranged from 99.7 to 100%, while the proportion of CD11b(+) Gr-1(-) lavage macrophages ranged from 77.0 to 80.0%. In contrast, few CD11b(-) CD45R(+) B lymphocytes from the lavage of the C. jejuni-injected mice were associated with green-fluorescent C. jejuni (proportions ranged from 0.75 to 0.77%). Cell-free C. jejuni was recovered from tissue homogenates after intraperitoneal injection. Macrorestriction profiling with pulsed-field gel electrophoresis identified a genotypic variant of the C. jejuni F38011 wild-type isolate. In vivo this variant displayed a phenotype identical to that of the wild-type isolate. In summary, we demonstrate that C. jejuni associates with marker-defined cellular subsets in vivo with a novel gfp reporter system and that C. jejuni genotypic variants can be isolated from both in vitro and in vivo systems.
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Affiliation(s)
- Philip F Mixter
- School of Molecular Biosciences, Washington State University, Pullman, WA 99164-4234, USA
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81
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Tournier JN, Hellmann AQ, Lesca G, Jouan A, Drouet E, Mathieu J. Fever-like thermal conditions regulate the activation of maturing dendritic cells. J Leukoc Biol 2003; 73:493-501. [PMID: 12660224 DOI: 10.1189/jlb.1002506] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
Fever is one of the most frequent clinical signs encountered in pathology, especially with respect to infectious diseases. It is currently thought that the role of fever on immunity is limited to activation of innate immunity; however, its relevance to activation of adaptive immunity remains unclear. Dendritic cells (DCs) that behave as sentinels of the immune system provide an important bridge between innate and adaptive immunity. To highlight the role of fever on adaptive immunity, we exposed murine bone marrow-derived lipopolysaccharide (LPS)- or live bacteria-maturing DCs over a 3-h period to 37 degrees C or to fever-like thermal conditions (39 degrees C or 40 degrees C). At these three temperatures, we measured the kinetics of cytokine production and the ability of DCs to induce an allogeneic mixed lymphocyte reaction. Our results show that short exposure of DCs to temperatures of 39 degrees C or 40 degrees C differentially increased the secretion of interleukin (IL)-12p70 and decreased the secretion of IL-10 and tumor necrosis factor alpha by maturing DCs. These fever-like conditions induced a regulation of cytokine production at the single-cell level. In addition, short-term exposed LPS-maturing DCs to 39 degrees C induced a stronger reaction with allogeneic CD4(+) T cells than maturing DCs incubated at 37 degrees C. These results provide evidence that temperature regulates cytokine secretion and DC functions, both of which are of particular importance in bacterial diseases.
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Affiliation(s)
- Jean-Nicolas Tournier
- Département de Biologie des agents Transmissibles, Centre de Recherches du Service de Santé des Armées, La Tronche cedex, France.
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82
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83
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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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84
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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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85
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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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86
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Goldmann O, Rohde M, Medina E. Phagocytosis of bacille Calmette-Guérin-infected necrotic macrophages induces a maturation phenotype and evokes antigen-presentation functions in dendritic cells. Immunology 2002; 107:500-6. [PMID: 12460195 PMCID: PMC1782828 DOI: 10.1046/j.1365-2567.2002.01536.x] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The interaction of pathogens with dendritic cells (DCs) seems to play a critical role in the initiation of the immune response. Tissue damage and induction of an inflammatory reaction are events frequently associated with the progression of the infection. Although DCs are very efficient at phagocytosing pathogens, the capacity of these cells to uptake microbes from a necrotic environment has not yet been proven. Here we have investigated the ability of murine bone marrow-derived DCs to maturate and acquire antigen-presentation functions when cocultured with bacille Calmette-Guérin (BCG)-infected necrotic macrophages. Immature DCs exhibited a prominent capacity to ingest necrotic material as demonstrated by flow cytometry analysis and confocal microscopy. Furthermore, after exposure to BCG-infected necrotic macrophages, DCs underwent phenotypic changes, including the up-regulation of maturation specific markers (major histocompatibility complex class II, CD40, CD80, and CD86) and the capacity to stimulate antigen-specific CD4+ T cells with higher efficiency than when they were directly infected with a similar number of bacteria. Antigen presentation following phagocytosis of BCG-infected necrotic macrophages was demonstrated by their ability to stimulate in vitro proliferation and interferon-gamma production of antigen-specific CD4+ T cells. These results suggest that the functional changes occurring in DCs after interaction with a pathogen can be favoured when the encounter takes place in a necrotic environment and it may constitute an important mechanism for the amplification of class II-restricted immune responses induced during infection.
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Affiliation(s)
- Oliver Goldmann
- Department of Microbial Pathogenesis and Vaccine Research, GBF-National Research Centre for Biotechnology, Braunschweig, Germany
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87
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Kirby AC, Yrlid U, Wick MJ. The innate immune response differs in primary and secondary Salmonella infection. JOURNAL OF IMMUNOLOGY (BALTIMORE, MD. : 1950) 2002; 169:4450-9. [PMID: 12370380 DOI: 10.4049/jimmunol.169.8.4450] [Citation(s) in RCA: 112] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
This study examines innate immunity to oral Salmonella during primary infection and after secondary challenge of immune mice. Splenic NK and NKT cells plummeted early after primary infection, while neutrophils and macrophages (Mphi) increased 10- and 3-fold, respectively. In contrast, immune animals had only a modest reduction in NK cells, no loss of NKT cells, and a slight increase in phagocytes following secondary challenge. During primary infection, the dominant sources of IFN-gamma were, unexpectedly, neutrophils and Mphi, the former having intracellular stores of IFN-gamma that were released during infection. IFN-gamma-producing phagocytes greatly outnumbered IFN-gamma-producing NK cells, NKT cells, and T cells during the primary response. TNF-alpha production was also dominated by neutrophils and Mphi, which vastly outnumbered NKT cells producing this cytokine. Neither T cells nor NK cells produced TNF-alpha early during primary infection. The TNF-alpha response was reduced in a secondary response, but remained dominated by neutrophils and Mphi. Moreover, no significant IFN-gamma production by Mphi was associated with the secondary response. Indeed, only NK1.1(+) cells and T cells produced IFN-gamma in these mice. These studies provide a coherent view of innate immunity to oral Salmonella infection, reveal novel sources of IFN-gamma, and demonstrate that immune status influences the nature of the innate response.
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Affiliation(s)
- Alun C Kirby
- Department of Cell and Molecular Biology, Section for Immunology, Lund University, Lund, Sweden
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88
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Wijburg OLC, Van Rooijen N, Strugnell RA. Induction of CD8+ T lymphocytes by Salmonella typhimurium is independent of Salmonella pathogenicity island 1-mediated host cell death. JOURNAL OF IMMUNOLOGY (BALTIMORE, MD. : 1950) 2002; 169:3275-83. [PMID: 12218147 DOI: 10.4049/jimmunol.169.6.3275] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Salmonella are intracellular bacterial pathogens that reside and replicate inside macrophages, and attenuated strains of Salmonella typhimurium can be used to deliver heterologous Ags for MHC class I and/or MHC class II-restricted presentation. Recently, it was shown that invasion of macrophages by S. typhimurium may result in the death of host macrophages via a mechanism harboring features of apoptotic and necrotic cell death. However, it is unknown whether this bacterial-induced host cell death affects immunity. In addition, it has been hypothesized that macrophage death following infection with S. typhimurium and subsequent uptake of apoptotic cells by APC are fundamental to the induction of CTL responses. In this study we investigated the in vivo induction of Ag-specific CD8+ T lymphocyte responses and compared CD8+ T lymphocyte responses elicited with S. typhimurium strains carrying a mutation in their invA gene, and therefore an inability to induce Salmonella pathogenicity island 1 (SPI-1)-mediated macrophage death, with responses elicited by an attenuated deltaaroAD strain. Ag-specific CD8+ T lymphocyte responses were analyzed using IFN-gamma ELISPOT, tetramer binding, and in vivo and in vitro CTL assays. Our results showed that deltaaroAD and deltaaroADdeltainvA induced comparable levels of Ag-specific CD8+ T lymphocyte responses as well as protective, Ag-specific B and CD4+ T lymphocyte immunity. Furthermore, experiments in macrophage-depleted mice showed that CD8+ T lymphocyte responses were effectively induced in the absence of macrophages. Together, our results imply that in this infection model, SPI-1-mediated cell death does not affect the immunological defense response and is not important for the induction of CD8+ T lymphocyte responses.
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MESH Headings
- Administration, Oral
- Animals
- Bacterial Proteins/genetics
- Bacterial Proteins/physiology
- CD8-Positive T-Lymphocytes/immunology
- CD8-Positive T-Lymphocytes/microbiology
- Cell Death/genetics
- Cell Death/immunology
- Cell Line
- Cells, Cultured
- Cytotoxicity, Immunologic/genetics
- Dogs
- Epitopes, T-Lymphocyte/immunology
- Gene Deletion
- Liver/cytology
- Liver/immunology
- Liver/microbiology
- Lymphocyte Activation/genetics
- Macrophages, Peritoneal/immunology
- Macrophages, Peritoneal/microbiology
- Macrophages, Peritoneal/pathology
- Male
- Mice
- Mice, Inbred C57BL
- Salmonella Infections, Animal/immunology
- Salmonella Infections, Animal/microbiology
- Salmonella Infections, Animal/pathology
- Salmonella Vaccines/administration & dosage
- Salmonella Vaccines/genetics
- Salmonella Vaccines/immunology
- Salmonella typhimurium/genetics
- Salmonella typhimurium/immunology
- Salmonella typhimurium/pathogenicity
- Spleen/cytology
- Spleen/immunology
- Spleen/microbiology
- Vaccines, Synthetic/administration & dosage
- Vaccines, Synthetic/genetics
- Vaccines, Synthetic/immunology
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Affiliation(s)
- Odilia L C Wijburg
- Department of Microbiology and Immunology and Cooperative Research Center for Vaccine Technology, University of Melbourne, Parkville, Victoria, Melbourne, Australia.
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89
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Pasetti MF, Salerno-Gonçalves R, Sztein MB. Salmonella enterica serovar Typhi live vector vaccines delivered intranasally elicit regional and systemic specific CD8+ major histocompatibility class I-restricted cytotoxic T lymphocytes. Infect Immun 2002; 70:4009-18. [PMID: 12117906 PMCID: PMC128131 DOI: 10.1128/iai.70.8.4009-4018.2002] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
We investigated the ability of live attenuated Salmonella enterica serovar Typhi strains delivered to mice intranasally to induce specific cytotoxic T-lymphocyte (CTL) responses at regional and systemic levels. Mice immunized with two doses (28 days apart) of Salmonella serovar Typhi strain Ty21a, the licensed oral typhoid vaccine, and genetically attenuated mutants CVD 908 (DeltaaroC DeltaaroD), CVD 915 (DeltaguaBA), and CVD 908-htrA (DeltaaroC DeltaaroD DeltahtrA) induced CTL specific for Salmonella serovar Typhi-infected cells in spleens and cervical lymph nodes. CTL were detected in effector T cells that had been expanded in vitro for 7 days in the presence of Salmonella-infected syngeneic splenocytes. A second round of stimulation further enhanced the levels of specific cytotoxicity. CTL activity was observed in sorted alphabeta+ CD8+ T cells, which were remarkably increased after expansion, but not in CD4+ T cells. CTL from both cervical lymph nodes and spleens failed to recognize Salmonella-infected major histocompatibility complex (MHC)-mismatched cells, indicating that the responses were MHC restricted. Studies in which MHC blocking antibodies were used showed that H-2L(d) was the restriction element. This is the first demonstration that Salmonella serovar Typhi vaccines delivered intranasally elicit CD8+ MHC class I-restricted CTL. The results further support the usefulness of the murine intranasal model for evaluating the immunogenicity of typhoid vaccine candidates at the preclinical level.
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Affiliation(s)
- Marcela F Pasetti
- Center for Vaccine Development, Department of Pediatrics, University of Maryland School of Medicine, Baltimore 21201, USA.
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90
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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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91
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Yrlid U, Wick MJ. Antigen presentation capacity and cytokine production by murine splenic dendritic cell subsets upon Salmonella encounter. JOURNAL OF IMMUNOLOGY (BALTIMORE, MD. : 1950) 2002; 169:108-16. [PMID: 12077235 DOI: 10.4049/jimmunol.169.1.108] [Citation(s) in RCA: 93] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Salmonella typhimurium is an intracellular bacterium that replicates in the spleen and mesenteric lymph nodes (MLN) of orally infected mice. However, little is known about the Ag presentation and cytokine production capacity of dendritic cells (DC), particularly CD8alpha(+), CD8alpha(-)CD4(-), and CD8alpha(-)CD4(+) DC, from these organs in response to Salmonella. Infection of purified splenic DC with S. typhimiurium expressing green fluorescent protein (GFP) and OVA revealed that all three splenic DC subsets internalize bacteria, and splenic as well as MLN DC process Salmonella for peptide presentation. Furthermore, presentation of Salmonella Ags on MHC-I and MHC-II was evident in both CD8alpha(+) and CD8alpha(-) splenic DC subsets. Direct ex vivo analysis of splenic DC from mice infected with GFP-expressing Salmonella showed that all three subsets harbored bacteria, and splenic DC purified from mice given Salmonella-expressing OVA presented OVA-derived peptides on MHC-I and MHC-II. Cytokine production analyzed by intracellular staining of splenic DC infected with GFP-expressing Salmonella revealed that TNF-alpha was produced by a large percentage of CD8alpha(-) DC, while only a minor proportion of CD8alpha(+) DC produced this cytokine following bacterial exposure. In contrast, the greatest number of IL-12p40-producing DC were among CD8alpha(+) DC. Experiments inhibiting bacterial uptake by cytochalasin D as well as use of a Transwell system revealed that bacterial contact, but not internalization, was required for cytokine production. Thus, DC in sites of Salmonella replication and T cell activation, spleen and MLN, respond to bacterial encounter by Ag presentation and produce cytokines in a subset-specific fashion.
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Affiliation(s)
- Ulf Yrlid
- Department of Cell and Molecular Biology, Section for Immunology, Lund University, Lund, Sweden
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92
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Bumann D. Examination of Salmonella gene expression in an infected mammalian host using the green fluorescent protein and two-colour flow cytometry. Mol Microbiol 2002; 43:1269-83. [PMID: 11918812 DOI: 10.1046/j.1365-2958.2002.02821.x] [Citation(s) in RCA: 79] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Quantitative data on Salmonella gene expression in infected hosts are largely lacking because of technical problems. One attractive reporter, the green fluorescent protein (GFP), is widely used in vitro but is difficult to quantify in infected tissues because of the preponderance of background particles with similar fluorescence. Here, bacterial GFP emission was spectrally distinguished from host autofluorescence by two-colour flow cytometry. Using this technique, the in vivo activity of three well-characterized promoters (PsicA, PssaH and PpagC) was determined. Their spatial and temporal activity patterns are in close agreement with predictions based on previous data and the colonization defects of corresponding deletion strains. To identify additional Salmonella promoters that are induced in infected animals, a genomic library was sorted by flow cytometry yielding four independent promoters. Genes expressed from PpibB and PsifA contribute to virulence, and chorismate mutase expressed from ParoQ might participate in aromatic acid biosynthesis, which is also required for virulence. Promoter P3g appears to be part of a mobile genetic element that is lacking in the completely sequenced strain LT2.
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Affiliation(s)
- Dirk Bumann
- Max-Planck-Institute for Infection Biology, Department of Molecular Biology, Schumannstrasse 21/22, D-10117 Berlin, Germany.
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