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Dolbec D, Lehoux M, de Beauville AA, Zahn A, Di Noia JM, Segura M. Unmutated but T cell dependent IgM antibodies targeting Streptococcus suis play an essential role in bacterial clearance. PLoS Pathog 2024; 20:e1011957. [PMID: 38241393 PMCID: PMC10829992 DOI: 10.1371/journal.ppat.1011957] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2023] [Revised: 01/31/2024] [Accepted: 01/08/2024] [Indexed: 01/21/2024] Open
Abstract
Streptococcus suis serotype 2 is an important encapsulated bacterial swine pathogen and zoonotic agent for which no effective vaccine exists. The interaction with B cells and the humoral response against S. suis are poorly understood despite their likely relevance for a potential vaccine. We evaluated germinal center (GC) B cell kinetics, as well as the production and role of S. suis-specific antibodies following infections in a mouse model. We found that mice infected with S. suis developed GC that peaked 13-21 days post-infection. GC further increased and persisted upon periodic reinfection that mimics real life conditions in swine farms. Anti-S. suis IgM and several IgG subclasses were produced, but antibodies against the S. suis capsular polysaccharide (CPS) were largely IgM. Interestingly, depletion of total IgG from the wild-type mice sera had no effect on bacterial killing by opsonophagocytosis in vitro. Somatic hypermutation and isotype switching were dispensable for controlling the infection or anti-CPS IgM production. However, T cell-deficient (Tcrb-/-) mice were unable to control bacteremia, produce optimal anti-CPS IgM titers, or elicit antibodies with opsonophagocytic activity. SAP deficiency, which prevents GC formation but not extrafollicular B cell responses, ablated anti S. suis-IgG production but maintained IgM production and eliminated the infection. In contrast, B cell deficient mice were unable to control bacteremia. Collectively, our results indicate that the antibody response plays a large role in immunity against S. suis, with GC-independent but T cell-dependent germline IgM being the major effective antibody specificities. Our results further highlight the importance IgM, and potentially anti-CPS antibodies, in clearing S. suis infections and provide insight for future development of S. suis vaccines.
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Affiliation(s)
- Dominic Dolbec
- Research Group on Infectious Diseases in Production Animals (GREMIP) and Swine and Poultry Infectious Diseases Research Center (CRIPA), Department of Pathology and Microbiology, Faculty of Veterinary Medicine, University of Montreal, Saint-Hyacinthe, Quebec, Canada
| | - Mélanie Lehoux
- Research Group on Infectious Diseases in Production Animals (GREMIP) and Swine and Poultry Infectious Diseases Research Center (CRIPA), Department of Pathology and Microbiology, Faculty of Veterinary Medicine, University of Montreal, Saint-Hyacinthe, Quebec, Canada
| | - Alexis Asselin de Beauville
- Research Group on Infectious Diseases in Production Animals (GREMIP) and Swine and Poultry Infectious Diseases Research Center (CRIPA), Department of Pathology and Microbiology, Faculty of Veterinary Medicine, University of Montreal, Saint-Hyacinthe, Quebec, Canada
| | - Astrid Zahn
- Institut de Recherches Cliniques de Montréal, Center for Immunity, Inflammation and Infectious Diseases, Quebec, Canada
| | - Javier Marcelo Di Noia
- Institut de Recherches Cliniques de Montréal, Center for Immunity, Inflammation and Infectious Diseases, Quebec, Canada
- Department of Medicine, Faculty of Sciences, University of Montreal, Montreal, Quebec, Canada
| | - Mariela Segura
- Research Group on Infectious Diseases in Production Animals (GREMIP) and Swine and Poultry Infectious Diseases Research Center (CRIPA), Department of Pathology and Microbiology, Faculty of Veterinary Medicine, University of Montreal, Saint-Hyacinthe, Quebec, Canada
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Dolbec D, Lehoux M, Okura M, Takamatsu D, Gottschalk M, Segura M. Streptococcus suis surface-antigen recognition by antibodies and bacterial elimination is influenced by capsular polysaccharide structure. Front Cell Infect Microbiol 2023; 13:1228496. [PMID: 37545852 PMCID: PMC10401424 DOI: 10.3389/fcimb.2023.1228496] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2023] [Accepted: 07/05/2023] [Indexed: 08/08/2023] Open
Abstract
Streptococcus suis is an encapsulated bacterium causing severe diseases in swine. Here, we compared the protective properties of the capsular polysaccharide (CPS) of different S. suis serotypes by using serotype-switched mutants in a mouse model of infection. CPS structure influenced bacterial survival in mice, antibody binding, and antibody-mediated bacterial killing. The CPS of serotypes 3, 4 and 14 allowed more antibody binding and bacterial elimination than the CPS of serotypes 2, 7 and 9. Results suggest that the different CPS structures of S. suis provide varying levels of protection by influencing antigen availability and elimination by the host immune system.
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Affiliation(s)
- Dominic Dolbec
- Research Group on Infectious Diseases in Production Animals (GREMIP) and Swine and Poultry Infectious Diseases Research Center (CRIPA), Department of Pathology and Microbiology, Faculty of Veterinary Medicine, University of Montreal, Saint-Hyacinthe, QC, Canada
| | - Mélanie Lehoux
- Research Group on Infectious Diseases in Production Animals (GREMIP) and Swine and Poultry Infectious Diseases Research Center (CRIPA), Department of Pathology and Microbiology, Faculty of Veterinary Medicine, University of Montreal, Saint-Hyacinthe, QC, Canada
| | - Masatoshi Okura
- Division of Transboundary Animal Disease Research, National Institute of Animal Health, National Agriculture and Food Research Organization, Kagoshima, Japan
| | - Daisuke Takamatsu
- Division of Infectious Animal Disease Research, National Institute of Animal Health, National Agriculture and Food Research Organization, Tsukuba, Japan
- The United Graduate School of Veterinary Sciences, Gifu University, Gifu, Japan
- Joint Graduate School of Veterinary Sciences, Gifu University, Gifu, Japan
| | - Marcelo Gottschalk
- Research Group on Infectious Diseases in Production Animals (GREMIP) and Swine and Poultry Infectious Diseases Research Center (CRIPA), Department of Pathology and Microbiology, Faculty of Veterinary Medicine, University of Montreal, Saint-Hyacinthe, QC, Canada
| | - Mariela Segura
- Research Group on Infectious Diseases in Production Animals (GREMIP) and Swine and Poultry Infectious Diseases Research Center (CRIPA), Department of Pathology and Microbiology, Faculty of Veterinary Medicine, University of Montreal, Saint-Hyacinthe, QC, Canada
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Breitfelder AK, Schrödl W, Rungelrath V, Baums CG, Alber G, Schütze N, Müller U. Immunoglobulin M-degrading enzyme of Streptococcus suis (Ide Ssuis ) impairs porcine B cell signaling. Front Immunol 2023; 14:1122808. [PMID: 36875121 PMCID: PMC9980343 DOI: 10.3389/fimmu.2023.1122808] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2022] [Accepted: 01/13/2023] [Indexed: 02/18/2023] Open
Abstract
Streptococcus suis (S. suis) is an important porcine pathogen, causing severe disease like meningitis and septicemia primarily in piglets. Previous work showed that the IgM-degrading enzyme of S. suis (Ide Ssuis ) specifically cleaves soluble porcine IgM and is involved in complement evasion. The objective of this study was to investigate Ide Ssuis cleavage of the IgM B cell receptor and subsequent changes in B cell receptor mediated signaling. Flow cytometry analysis revealed cleavage of the IgM B cell receptor by recombinant (r) Ide Ssuis _homologue as well as Ide Ssuis derived from culture supernatants of S. suis serotype 2 on porcine PBMCs and mandibular lymph node cells. Point-mutated rIde Ssuis _homologue_C195S did not cleave the IgM B cell receptor. After receptor cleavage by rIde Ssuis _homologue, it took at least 20 h for mandibular lymph node cells to restore the IgM B cell receptor to levels comparable to cells previously treated with rIde Ssuis _homologue_C195S. B cell receptor mediated signaling after specific stimulation via the F(ab')2 portion was significantly inhibited by rIde Ssuis _homologue receptor cleavage in IgM+ B cells, but not in IgG+ B cells. Within IgM+ cells, CD21+ B2 cells and CD21- B1-like cells were equally impaired in their signaling capacity upon rIde Ssuis _homologue B cell receptor cleavage. In comparison, intracellular B cell receptor independent stimulation with tyrosine phosphatase inhibitor pervanadate increased signaling in all investigated B cell types. In conclusion, this study demonstrates Ide Ssuis cleavage efficacy on the IgM B cell receptor and its consequences for B cell signaling.
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Affiliation(s)
- Annika Katharina Breitfelder
- Institute of Bacteriology and Mycology, Centre for Infectious Diseases, Faculty of Veterinary Medicine, University of Leipzig, Leipzig, Germany
| | - Wieland Schrödl
- Institute of Bacteriology and Mycology, Centre for Infectious Diseases, Faculty of Veterinary Medicine, University of Leipzig, Leipzig, Germany
| | - Viktoria Rungelrath
- Institute of Bacteriology and Mycology, Centre for Infectious Diseases, Faculty of Veterinary Medicine, University of Leipzig, Leipzig, Germany
| | - Christoph Georg Baums
- Institute of Bacteriology and Mycology, Centre for Infectious Diseases, Faculty of Veterinary Medicine, University of Leipzig, Leipzig, Germany
| | - Gottfried Alber
- Institute of Immunology, Centre for Infectious Diseases, Faculty of Veterinary Medicine, University of Leipzig, Leipzig, Germany
| | - Nicole Schütze
- Institute of Immunology, Centre for Infectious Diseases, Faculty of Veterinary Medicine, University of Leipzig, Leipzig, Germany
| | - Uwe Müller
- Institute of Immunology, Centre for Infectious Diseases, Faculty of Veterinary Medicine, University of Leipzig, Leipzig, Germany
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Wang S, Wang G, Tang YD, Li S, Qin L, Wang M, Yang YB, Gottschalk M, Cai X. Streptococcus suis Serotype 2 Infection Induces Splenomegaly with Splenocyte Apoptosis. Microbiol Spectr 2022; 10:e0321022. [PMID: 36287014 PMCID: PMC9769541 DOI: 10.1128/spectrum.03210-22] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2022] [Accepted: 10/01/2022] [Indexed: 01/10/2023] Open
Abstract
Little is known about the damage to the important peripheral immune organ spleen caused by Streptococcus suis infection. In this study, we found that S. suis induced splenomegaly and lymphocyte disruption in spleens of mice. To explore the mechanism of splenic lesions induced by S. suis, we conducted further studies. The results showed that S. suis induced apoptosis in B cells, which is related to the cleavage of caspase-3 and caspase-8, but not the release of apoptosis-inducing factor (AIF). Thus, S. suis induced apoptosis in the spleen through caspase-dependent and AIF-independent pathways. Inflammation lesions induced in the spleen of infected mice were also investigated; we found macrophages increased in histopathological lesions of infected spleens from 12 h postinoculation to 7 days postinoculation (dpi), and the type of increased macrophages was M1 type by confocal microscopy, which can secrete proinflammatory cytokines. Meanwhile, inflammasome NLRP3 and caspase-1 were activated, and gasdermin D (GSDMD) was cleaved, which causes pyroptosis that may result in the release of numerous proinflammatory cytokines. What's more, the increase of p-JNK and p-p38 indicated that the MAPK pathway was also involved in the proinflammatory responses during S. suis infection, whereas anti-inflammatory responses in spleen were suppressed, with regulatory T cells (Tregs) upregulating at 1 dpi. Taken together, proinflammatory immune responses dominate in early infection, which induce splenomegaly and splenocyte apoptosis. This is the first report of mechanisms associated with S. suis-induced splenic lesions. IMPORTANCE Streptococcus suis serotype 2 is considered an emerging pathogen and represents a threat to humans and animals. The spleen is an important peripheral immune organ, and splenomegaly is a consequence of lesions and an important clinical indicator of S. suis infection. However, knowledge of the mechanisms underlying spleen lesions is still very limited. In the present work, we made the investigation to explain the phenomenon and the related immunomodulation in a mouse infection model. The obtained results show that inflammation contributes to splenomegaly, while apoptosis contributes to lymphocyte disruption in spleens. Related signaling pathways were discovered which have never been associated with S. suis-induced splenic injury. The new knowledge generated will help us better understand the mechanism of S. suis pathogenesis.
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Affiliation(s)
- Shujie Wang
- State Key Laboratory of Veterinary Biotechnology, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Harbin, China
- Heilongjiang Provincial Key Laboratory of Veterinary Immunology, Harbin, China
| | - Gang Wang
- Shandong Provincial Key Laboratory of Animal Biotechnology and Disease Control and Prevention, College of Veterinary Medicine, Shandong Agricultural University, Taian, China
| | - Yan-Dong Tang
- State Key Laboratory of Veterinary Biotechnology, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Harbin, China
| | - Siqi Li
- State Key Laboratory of Veterinary Biotechnology, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Harbin, China
| | - Lei Qin
- State Key Laboratory of Veterinary Biotechnology, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Harbin, China
| | - Menghang Wang
- State Key Laboratory of Veterinary Biotechnology, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Harbin, China
| | - Yong-Bo Yang
- State Key Laboratory of Veterinary Biotechnology, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Harbin, China
| | - Marcelo Gottschalk
- Research Group on Infectious Diseases in Production Animals (GREMIP) and Swine and Poultry Infectious Diseases Research Center (CRIPA), Faculty of Veterinary Medicine, University of Montreal, Saint-Hyacinthe, Quebec, Canada
| | - Xuehui Cai
- State Key Laboratory of Veterinary Biotechnology, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Harbin, China
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Streptococcus suis Serotype 2 Infection Causes Host Immunomodulation through Induction of Thymic Atrophy. Infect Immun 2020; 88:IAI.00950-19. [PMID: 31932328 DOI: 10.1128/iai.00950-19] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2019] [Accepted: 01/04/2020] [Indexed: 02/05/2023] Open
Abstract
Streptococcus suis serotype 2 is an important bacterial pathogen of swine and is also an emerging zoonotic agent that may be harmful to human health. Although the virulence genes of S. suis have been extensively studied, the mechanisms by which they damage the central immune organs have rarely been studied. In the current work, we wanted to uncover more details about the impact and mechanisms of S. suis on specific populations of thymic and immune cells in infected mice. Terminal deoxynucleotidyl transferase (TdT)-mediated dUTP-biotin nick end labeling (TUNEL) assays revealed that S. suis infection induced apoptosis in CD3+, CD14+, and epithelial cells from the thymus. S. suis infection resulted in a rapid depletion of mitochondrial permeability and release of cytochrome c (CytC) and apoptosis-inducing factor (AIF) through upregulation of Bax expression and downregulation of Bcl-xl and Bcl2 expression in thymocytes. Moreover, S. suis infection increased cleavage of caspase-3, caspase-8, and caspase-9. Thus, S. suis induced thymocyte apoptosis through a p53- and caspase-dependent pathway, which led to a decrease of CD3+ cells in the thymus, subsequently decreasing the numbers of CD4+ and CD8+ cells in the peripheral blood. Finally, expression dysregulation of proinflammatory cytokines in the serum, including interleukin 2 (IL-2), IL-6, IL-12 (p70), tumor necrosis factor (TNF), and IL-10, was observed in mice after S. suis type 2 infection. Taken together, these results suggest that S. suis infection can cause atrophy of the thymus and induce apoptosis of thymocytes in mice, thus likely suppressing host immunity.
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Rieckmann K, Seydel A, Klose K, Alber G, Baums CG, Schütze N. Vaccination with the immunoglobulin M-degrading enzyme of Streptococcus suis, Ide Ssuis, leads to protection against a highly virulent serotype 9 strain. Vaccine X 2019; 3:100046. [PMID: 31709420 PMCID: PMC6831886 DOI: 10.1016/j.jvacx.2019.100046] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2019] [Revised: 10/03/2019] [Accepted: 10/06/2019] [Indexed: 01/10/2023] Open
Abstract
IdeSsuis vaccination of piglets significantly reduced survival of S. suis cps9 in blood. IdeSsuis reactive T helper cells producing TNF-α, IL-17A or IFN-ɣ were detectable. Vaccination resulted in protection against mortality induced by cps9 challenge.
Vaccination of weaning piglets with the recombinant IgM degrading enzyme of Streptococcus suis (S. suis), rIdeSsuis, elicits protection against disease caused by serotype (cps) 2 infection. In Europe, S. suis cps9 is at least as important as cps2 in causing severe herd problems associated with meningitis, septicemia and arthritis. The objective of this study was to determine humoral and cellular immunogenicities of rIdeSsuis suckling piglet vaccination and to investigate protection against a virulent cps9 strain. Vaccination in the 2nd and 4th week of life with rIdeSsuis and an oil-in-water adjuvant induced seroconversion against IdeSsuis in 13 of 20 vaccinated piglets. In the 5th week, survival of the S. suis cps9 strain was significantly reduced in the blood of prime-booster vaccinated piglets. After a 2nd booster vaccination IdeSsuis-reactive T helper (Th) cells partially producing TNF-α, IL-17A or IFN-ɣ were detectable in rIdeSsuis-vaccinated but not in placebo-treated piglets and frequencies of IdeSsuis-reactive Th cells correlated with α-IdeSsuis–IgG levels. An intravenous challenge, conducted with a cps9 strain of sequence type (ST) 94, led to 89% mortality in placebo-treated piglets due to septicemia and meningitis. In contrast, all rIdeSsuis prime-booster-booster vaccinated littermates survived the challenge despite signs of disease such as fever and lameness. In conclusion, the described rIdeSsuis vaccination induces humoral and detectable IdeSsuis-reactive Th cell responses and leads to protection against a highly virulent cps9 strain.
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Affiliation(s)
- Karoline Rieckmann
- Institute of Bacteriology and Mycology, Centre for Infectious Diseases, Faculty of Veterinary Medicine, Leipzig University, Leipzig, Germany
| | - Anna Seydel
- Institute of Bacteriology and Mycology, Centre for Infectious Diseases, Faculty of Veterinary Medicine, Leipzig University, Leipzig, Germany
| | - Kristin Klose
- Institute of Pathology, Faculty of Veterinary Medicine, Leipzig University, Leipzig, Germany
| | - Gottfried Alber
- Institute of Immunology, Centre for Infectious Diseases, Faculty of Veterinary Medicine, Leipzig University, Leipzig, Germany
| | - Christoph G Baums
- Institute of Bacteriology and Mycology, Centre for Infectious Diseases, Faculty of Veterinary Medicine, Leipzig University, Leipzig, Germany
| | - Nicole Schütze
- Institute of Immunology, Centre for Infectious Diseases, Faculty of Veterinary Medicine, Leipzig University, Leipzig, Germany
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Beutler J, Jentsch HFR, Rodloff AC, Stingu CS. Bacteremia after professional mechanical plaque removal in patients with chronic periodontitis. Oral Dis 2019; 25:1185-1194. [PMID: 30680855 DOI: 10.1111/odi.13047] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2018] [Revised: 11/26/2018] [Accepted: 01/13/2019] [Indexed: 01/09/2023]
Abstract
OBJECTIVE The aim of this study was to investigate the characteristics of bacteremia caused by professional mechanical plaque removal (PMPR) in two groups of patients with generalized moderate chronic periodontitis. MATERIALS AND METHODS Venous blood samples were taken at multiple time points for one hour following PMPR in fifty patients with generalized moderate chronic periodontitis. Subjects consisted of two groups, one group was receiving supportive periodontal therapy (SPT, n = 25) and the other group was receiving initial periodontal therapy (IPT, n = 25). Blood samples were processed and analyzed for cultivable microflora. Pertinent clinical parameters were recorded for each patient in both groups. RESULTS Bacteremia was detected in 10 of 25 SPT and 8 of 25 IPT patients (p = 0.796). In both groups, the prevalence of bacteremia was dependent on the time of blood sampling and varied in magnitude between <102 CFU/ml and 106 CFU/ml. Sixteen different bacterial species were identified in both groups, mostly Actinomyces naeslundii (SPT n = 3, IPT n = 4) and Streptococcus spp. (SPT n = 6, IPT n = 2). In regression models, Grade II furcation involvement (p = 0.004) and Gingival Bleeding Index (p = 0.036) had affected the occurrence of bacteremia but in the SPT group only. CONCLUSION Professional mechanical plaque removal was associated with bacteremia regardless of whether a patient was receiving SPT or IPT.
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Affiliation(s)
- Jakob Beutler
- Center for Periodontology, Department of Cariology, Endodontology and Periodontology, University Hospital of Leipzig, Leipzig, Germany
| | - Holger F R Jentsch
- Center for Periodontology, Department of Cariology, Endodontology and Periodontology, University Hospital of Leipzig, Leipzig, Germany
| | - Arne C Rodloff
- Institute of Medical Microbiology and Epidemiology on Infectious Diseases, Leipzig, Germany
| | - Catalina-Suzana Stingu
- Institute of Medical Microbiology and Epidemiology on Infectious Diseases, Leipzig, Germany
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Letendre C, Auger JP, Lemire P, Galbas T, Gottschalk M, Thibodeau J, Segura M. Streptococcus suis Serotype 2 Infection Impairs Interleukin-12 Production and the MHC-II-Restricted Antigen Presentation Capacity of Dendritic Cells. Front Immunol 2018; 9:1199. [PMID: 29899744 PMCID: PMC5988873 DOI: 10.3389/fimmu.2018.01199] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2017] [Accepted: 05/14/2018] [Indexed: 01/18/2023] Open
Abstract
Streptococcus suis is an important swine pathogen and emerging zoonotic agent. Encapsulated strains of S. suis modulate dendritic cell (DC) functions, leading to poorly activated CD4+ T cells. However, the antigen presentation ability of S. suis-stimulated DCs has not been investigated yet. In this work, we aimed to characterize the antigen presentation profiles of S. suis-stimulated DCs, both in vitro and in vivo. Upon direct activation in vitro, S. suis-stimulated murine bone marrow-derived DCs (bmDCs) preserved their antigen capture/processing capacities. However, they showed delayed kinetics of MHC-II expression compared to lipopolysaccharide-stimulated bmDCs. Meanwhile, splenic DCs from infected mice exhibited a compromised MHC-II expression, despite an appropriate expression of maturation markers. To identify potential interfering mechanisms, Class II Major Histocompatibility Complex Transactivator (CIITA) and membrane-associated RING-CH (MARCH)1/8 transcription were studied. S. suis-stimulated DCs maintained low levels of CIITA at early time points, both in vitro and in vivo, which could limit their ability to increase MHC-II synthesis. S. suis-stimulated DCs also displayed sustained/upregulated levels of MARCH1/8, thus possibly leading to MHC-II lysosomal degradation. The bacterial capsular polysaccharide played a partial role in this modulation. Finally, interleukin (IL)-12p70 production was inhibited in splenic DCs from infected mice, a profile compatible with DC indirect activation by pro-inflammatory compounds. Consequently, these cells induced lower levels of IL-2 and TNF-α in an antigen-specific CD4+ T cell presentation assay and blunted T cell CD25 expression. It remains unclear at this stage whether these phenotypical and transcriptional modulations observed in response to S. suis in in vivo infections are part of a bacterial immune evasion strategy or rather a feature common to systemic inflammatory response-inducing agents. However, it appears that the MHC-II-restricted antigen presentation and Th1-polarizing cytokine production capacities of DCs are impaired during S. suis infection. This study highlights the potential consequences of inflammation on the type and magnitude of the immune response elicited by a pathogen.
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Affiliation(s)
- Corinne Letendre
- Laboratory of Immunology, Faculty of Veterinary Medicine, University of Montreal, Saint-Hyacinthe, QC, Canada
| | - Jean-Philippe Auger
- Laboratory of Research on Streptococcus suis, Faculty of Veterinary Medicine, University of Montreal, Saint-Hyacinthe, QC, Canada
| | - Paul Lemire
- Laboratory of Immunology, Faculty of Veterinary Medicine, University of Montreal, Saint-Hyacinthe, QC, Canada
| | - Tristan Galbas
- Laboratory of Molecular Immunology, Department of Microbiology, Infectiology and Immunology, University of Montreal, Montreal, QC, Canada
| | - Marcelo Gottschalk
- Laboratory of Research on Streptococcus suis, Faculty of Veterinary Medicine, University of Montreal, Saint-Hyacinthe, QC, Canada
| | - Jacques Thibodeau
- Laboratory of Molecular Immunology, Department of Microbiology, Infectiology and Immunology, University of Montreal, Montreal, QC, Canada
| | - Mariela Segura
- Laboratory of Immunology, Faculty of Veterinary Medicine, University of Montreal, Saint-Hyacinthe, QC, Canada
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Auger JP, Santinón A, Roy D, Mossman K, Xu J, Segura M, Gottschalk M. Type I Interferon Induced by Streptococcus suis Serotype 2 is Strain-Dependent and May Be Beneficial for Host Survival. Front Immunol 2017; 8:1039. [PMID: 28894449 PMCID: PMC5581389 DOI: 10.3389/fimmu.2017.01039] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2017] [Accepted: 08/11/2017] [Indexed: 12/16/2022] Open
Abstract
Streptococcus suis serotype 2 is an important porcine bacterial pathogen and emerging zoonotic agent mainly responsible for sudden death, septic shock, and meningitis, with exacerbated inflammation being a hallmark of the infection. However, serotype 2 strains are genotypically and phenotypically heterogeneous, being composed of a multitude of sequence types (STs) whose virulence greatly varies: the virulent ST1 (Eurasia), highly virulent ST7 (responsible for the human outbreaks in China), and intermediate virulent ST25 (North America) are the most important worldwide. Even though type I interferons (IFNs) are traditionally associated with important antiviral functions, recent studies have demonstrated that they may also play an important role during infections with extracellular bacteria. Upregulation of IFN-β levels was previously observed in mice following infection with this pathogen. Consequently, the implication of IFN-β in the S. suis serotype 2 pathogenesis, which has always been considered a strict extracellular bacterium, was evaluated using strains of varying virulence. This study demonstrates that intermediate virulent strains are significantly more susceptible to phagocytosis than virulent strains. Hence, subsequent localization of these strains within the phagosome results in recognition of bacterial nucleic acids by Toll-like receptors 7 and 9, leading to activation of the interferon regulatory factors 1, 3, and 7 and production of IFN-β. Type I IFN, whose implication depends on the virulence level of the S. suis strain, is involved in host defense by participating in the modulation of systemic inflammation, which is responsible for the clearance of blood bacterial burden. As such, when induced by intermediate, and to a lesser extent, virulent S. suis strains, type I IFN plays a beneficial role in host survival. The highly virulent ST7 strain, however, hastily induces a septic shock that cannot be controlled by type I IFN, leading to rapid death of the host. A better understanding of the underlying mechanisms involved in the control of inflammation and subsequent bacterial burden could help to develop control measures for this important porcine and zoonotic agent.
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Affiliation(s)
- Jean-Philippe Auger
- Research Group on Infectious Diseases in Production Animals (GREMIP), Swine and Poultry Infectious Diseases Research Center (CRIPA), Faculty of Veterinary Medicine, Department of Pathology and Microbiology, University of Montreal, Saint-Hyacinthe, QC, Canada
| | - Agustina Santinón
- Research Group on Infectious Diseases in Production Animals (GREMIP), Swine and Poultry Infectious Diseases Research Center (CRIPA), Faculty of Veterinary Medicine, Department of Pathology and Microbiology, University of Montreal, Saint-Hyacinthe, QC, Canada
| | - David Roy
- Research Group on Infectious Diseases in Production Animals (GREMIP), Swine and Poultry Infectious Diseases Research Center (CRIPA), Faculty of Veterinary Medicine, Department of Pathology and Microbiology, University of Montreal, Saint-Hyacinthe, QC, Canada
| | - Karen Mossman
- Department of Biochemistry and Biomedical Sciences, McMaster University, Hamilton, ON, Canada
| | - Jianguo Xu
- Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, National Institute for Communicable Disease Control and Prevention, Chinese Center for Disease Control and Prevention, Beijing, China
| | - Mariela Segura
- Research Group on Infectious Diseases in Production Animals (GREMIP), Swine and Poultry Infectious Diseases Research Center (CRIPA), Faculty of Veterinary Medicine, Department of Pathology and Microbiology, University of Montreal, Saint-Hyacinthe, QC, Canada
| | - Marcelo Gottschalk
- Research Group on Infectious Diseases in Production Animals (GREMIP), Swine and Poultry Infectious Diseases Research Center (CRIPA), Faculty of Veterinary Medicine, Department of Pathology and Microbiology, University of Montreal, Saint-Hyacinthe, QC, Canada
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Lemire P, Galbas T, Thibodeau J, Segura M. Natural Killer Cell Functions during the Innate Immune Response to Pathogenic Streptococci. Front Microbiol 2017; 8:1196. [PMID: 28706510 PMCID: PMC5489694 DOI: 10.3389/fmicb.2017.01196] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2017] [Accepted: 06/12/2017] [Indexed: 01/21/2023] Open
Abstract
Dendritic cells (DCs) and NK cells play a crucial role in the first phase of host defense against infections. Group B Streptococcus (GBS) and Streptococcus suis are encapsulated streptococci causing severe systemic inflammation, leading to septicemia and meningitis. Yet, the involvement of NK cells in the innate immune response to encapsulated bacterial infection is poorly characterized. Here, it was observed that these two streptococcal species rapidly induce the release of IFN-γ and that NK cells are the major cell type responsible for this production during the acute phase of the infection. Albeit S. suis capacity to activate NK cells was lower than that of GBS, these cells partially contribute to S. suis systemic infection; mainly through amplification of the inflammatory loop. In contrast, such a role was not observed during GBS systemic infection. IFN-γ release by NK cells required the presence of DCs, which in turn had a synergistic effect on DC cytokine production. These responses were mainly mediated by direct DC-NK cell contact and partially dependent on soluble factors. Though IL-12 and LFA-1 were shown to be critical in S. suis-mediated activation of the DC-NK cell crosstalk, different or redundant molecular pathways modulate DC-NK interactions during GBS infection. The bacterial capsular polysaccharides also differently modulated NK cell activation. Together, these results demonstrated a role of NK cells in the innate immune response against encapsulated streptococcal infections; yet the molecular pathways governing NK activation seem to differ upon the pathogen and should not be generalized when studying bacterial infections.
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Affiliation(s)
- Paul Lemire
- Laboratory of Immunology of the Swine and Poultry Infectious Diseases Research Centre, Faculty of Veterinary Medicine, University of MontrealSt-Hyacinthe, QC, Canada
| | - Tristan Galbas
- Laboratory of Molecular Immunology, Faculty of Medicine, University of MontrealMontreal, QC, Canada
| | - Jacques Thibodeau
- Laboratory of Molecular Immunology, Faculty of Medicine, University of MontrealMontreal, QC, Canada
| | - Mariela Segura
- Laboratory of Immunology of the Swine and Poultry Infectious Diseases Research Centre, Faculty of Veterinary Medicine, University of MontrealSt-Hyacinthe, QC, Canada
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Ebner F, Schwiertz P, Steinfelder S, Pieper R, Zentek J, Schütze N, Baums CG, Alber G, Geldhof P, Hartmann S. Pathogen-Reactive T Helper Cell Analysis in the Pig. Front Immunol 2017; 8:565. [PMID: 28567041 PMCID: PMC5434156 DOI: 10.3389/fimmu.2017.00565] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2017] [Accepted: 04/27/2017] [Indexed: 11/29/2022] Open
Abstract
There is growing interest in studying host–pathogen interactions in human-relevant large animal models such as the pig. Despite the progress in developing immunological reagents for porcine T cell research, there is an urgent need to directly assess pathogen-specific T cells—an extremely rare population of cells, but of upmost importance in orchestrating the host immune response to a given pathogen. Here, we established that the activation marker CD154 (CD40L), known from human and mouse studies, identifies also porcine antigen-reactive CD4+ T lymphocytes. CD154 expression was upregulated early after antigen encounter and CD4+CD154+ antigen-reactive T cells coexpressed cytokines. Antigen-induced expansion and autologous restimulation enabled a time- and dose-resolved analysis of CD154 regulation and a significantly increased resolution in phenotypic profiling of antigen-responsive cells. CD154 expression identified T cells responding to staphylococcal Enterotoxin B superantigen stimulation as well as T cells responding to the fungus Candida albicans and T cells specific for a highly prevalent intestinal parasite, the nematode Ascaris suum during acute and trickle infection. Antigen-reactive T cells were further detected after immunization of pigs with a single recombinant bacterial antigen of Streptococcus suis only. Thus, our study offers new ways to study antigen-specific T lymphocytes in the pig and their contribution to host–pathogen interactions.
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Affiliation(s)
- Friederike Ebner
- Department of Veterinary Medicine, Institute of Immunology, Freie Universität Berlin, Berlin, Germany
| | - Patrycja Schwiertz
- Department of Veterinary Medicine, Institute of Immunology, Freie Universität Berlin, Berlin, Germany
| | - Svenja Steinfelder
- Department of Veterinary Medicine, Institute of Immunology, Freie Universität Berlin, Berlin, Germany
| | - Robert Pieper
- Department of Veterinary Medicine, Institute of Animal Nutrition, Freie Universität Berlin, Berlin, Germany
| | - Jürgen Zentek
- Department of Veterinary Medicine, Institute of Animal Nutrition, Freie Universität Berlin, Berlin, Germany
| | - Nicole Schütze
- Faculty of Veterinary Medicine, Institute of Immunology, Centre for Infectious Diseases, University of Leipzig, Leipzig, Germany
| | - Christoph G Baums
- Faculty of Veterinary Medicine, Institute for Bacteriology and Mycology, Centre for Infectious Diseases, University of Leipzig, Leipzig, Germany
| | - Gottfried Alber
- Faculty of Veterinary Medicine, Institute of Immunology, Centre for Infectious Diseases, University of Leipzig, Leipzig, Germany
| | - Peter Geldhof
- Laboratory of Parasitology, Faculty of Veterinary Medicine, Ghent University, Merelbeke, Belgium
| | - Susanne Hartmann
- Department of Veterinary Medicine, Institute of Immunology, Freie Universität Berlin, Berlin, Germany
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