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Crowder CD, Ghalyanchi Langeroudi A, Shojaee Estabragh A, Lewis ERG, Marcsisin RA, Barbour AG. Pathogen and Host Response Dynamics in a Mouse Model of Borrelia hermsii Relapsing Fever. Vet Sci 2016; 3:vetsci3030019. [PMID: 29056727 PMCID: PMC5606581 DOI: 10.3390/vetsci3030019] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2016] [Revised: 08/23/2016] [Accepted: 08/24/2016] [Indexed: 11/23/2022] Open
Abstract
Most Borrelia species that cause tick-borne relapsing fever utilize rodents as their natural reservoirs, and for decades laboratory-bred rodents have served as informative experimental models for the disease. However, while there has much progress in understanding the pathogenetic mechanisms, including antigenic variation, of the pathogen, the host side of the equation has been neglected. Using different approaches, we studied, in immunocompetent inbred mice, the dynamics of infection with and host responses to North American relapsing fever agent B. hermsii. The spirochete’s generation time in blood of infected mice was between 4–5 h and, after a delay, was matched in rate by the increase of specific agglutinating antibodies in response to the infection. After initiating serotype cells were cleared by antibodies, the surviving spirochetes were a different serotype and, as a population, grew more slowly. The retardation was attributable to the host response and not an inherently slower growth rate. The innate responses at infection peak and immediate aftermath were characterized by elevations of both pro-inflammatory and anti-inflammatory cytokines and chemokines. Immunodeficient mice had higher spirochete burdens and severe anemia, which was accounted for by aggregation of erythrocytes by spirochetes and their partially reversible sequestration in greatly enlarged spleens and elsewhere.
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Affiliation(s)
- Christopher D Crowder
- Departments of Microbiology & Molecular Genetics and Medicine, University of California Irvine, Irvine, CA 92697, USA.
| | - Arash Ghalyanchi Langeroudi
- Departments of Microbiology & Molecular Genetics and Medicine, University of California Irvine, Irvine, CA 92697, USA.
| | - Azadeh Shojaee Estabragh
- Departments of Microbiology & Molecular Genetics and Medicine, University of California Irvine, Irvine, CA 92697, USA.
| | - Eric R G Lewis
- Departments of Microbiology & Molecular Genetics and Medicine, University of California Irvine, Irvine, CA 92697, USA.
| | - Renee A Marcsisin
- Departments of Microbiology & Molecular Genetics and Medicine, University of California Irvine, Irvine, CA 92697, USA.
| | - Alan G Barbour
- Departments of Microbiology & Molecular Genetics and Medicine, University of California Irvine, Irvine, CA 92697, USA.
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Wagemakers A, Koetsveld J, Narasimhan S, Wickel M, Deponte K, Bleijlevens B, Jahfari S, Sprong H, Karan LS, Sarksyan DS, van der Poll T, Bockenstedt LK, Bins AD, Platonov AE, Fikrig E, Hovius JW. Variable Major Proteins as Targets for Specific Antibodies against Borrelia miyamotoi. THE JOURNAL OF IMMUNOLOGY 2016; 196:4185-95. [PMID: 27076681 DOI: 10.4049/jimmunol.1600014] [Citation(s) in RCA: 46] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/06/2016] [Accepted: 03/13/2016] [Indexed: 11/19/2022]
Abstract
Borrelia miyamotoi is a relapsing fever spirochete in Ixodes ticks that has been recently identified as a human pathogen causing hard tick-borne relapsing fever (HTBRF) across the Northern Hemisphere. No validated serologic test exists, and current serologic assays have low sensitivity in early HTBRF. To examine the humoral immune response against B. miyamotoi, we infected C3H/HeN mice with B. miyamotoi strain LB-2001 expressing variable small protein 1 (Vsp1) and demonstrated that spirochetemia was cleared after 3 d, coinciding with anti-Vsp1 IgM production. Clearance was also observed after passive transfer of immune sera to infected SCID mice. Next, we showed that anti-Vsp1 IgG eliminates Vsp1-expressing B. miyamotoi, selecting for spirochetes expressing a variable large protein (VlpC2) resistant to anti-Vsp1. The viability of Asian isolate B. miyamotoi HT31, expressing Vlp15/16 and Vlp18, was also unaffected by anti-Vsp1. Finally, in nine HTBRF patients, we demonstrated IgM reactivity to Vsp1 in two and against Vlp15/16 in four ∼1 wk after these patients tested positive for B. miyamotoi by PCR. Our data show that B. miyamotoi is able to express various variable major proteins (VMPs) to evade humoral immunity and that VMPs are antigenic in humans. We propose that serologic tests based on VMPs are of additional value in diagnosing HTBRF.
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Affiliation(s)
- Alex Wagemakers
- Center for Experimental and Molecular Medicine, Academic Medical Center, University of Amsterdam, 1105 AZ Amsterdam, the Netherlands; Section of Infectious Diseases, Department of Internal Medicine, Yale University School of Medicine, New Haven, CT 06520
| | - Joris Koetsveld
- Center for Experimental and Molecular Medicine, Academic Medical Center, University of Amsterdam, 1105 AZ Amsterdam, the Netherlands
| | - Sukanya Narasimhan
- Section of Infectious Diseases, Department of Internal Medicine, Yale University School of Medicine, New Haven, CT 06520
| | - Melvin Wickel
- Center for Experimental and Molecular Medicine, Academic Medical Center, University of Amsterdam, 1105 AZ Amsterdam, the Netherlands
| | - Kathleen Deponte
- Section of Infectious Diseases, Department of Internal Medicine, Yale University School of Medicine, New Haven, CT 06520
| | - Boris Bleijlevens
- Department of Medical Biochemistry, Academic Medical Center, University of Amsterdam, 1105 AZ Amsterdam, the Netherlands
| | - Seta Jahfari
- Center for Infectious Disease Control, National Institute for Public Health and the Environment, 3720 BA Bilthoven, the Netherlands
| | - Hein Sprong
- Center for Infectious Disease Control, National Institute for Public Health and the Environment, 3720 BA Bilthoven, the Netherlands
| | - Lyudmila S Karan
- Central Research Institute of Epidemiology, Moscow 111123, Russia
| | | | - Tom van der Poll
- Center for Experimental and Molecular Medicine, Academic Medical Center, University of Amsterdam, 1105 AZ Amsterdam, the Netherlands
| | - Linda K Bockenstedt
- Section of Rheumatology, Department of Internal Medicine, Yale University School of Medicine, New Haven, CT 06510
| | - Adriaan D Bins
- Center for Experimental and Molecular Medicine, Academic Medical Center, University of Amsterdam, 1105 AZ Amsterdam, the Netherlands
| | | | - Erol Fikrig
- Section of Infectious Diseases, Department of Internal Medicine, Yale University School of Medicine, New Haven, CT 06520
| | - Joppe W Hovius
- Center for Experimental and Molecular Medicine, Academic Medical Center, University of Amsterdam, 1105 AZ Amsterdam, the Netherlands;
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Bohannon JK, Hernandez A, Enkhbaatar P, Adams WL, Sherwood ER. The immunobiology of toll-like receptor 4 agonists: from endotoxin tolerance to immunoadjuvants. Shock 2014; 40:451-62. [PMID: 23989337 DOI: 10.1097/shk.0000000000000042] [Citation(s) in RCA: 104] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Lipopolysaccharide (LPS, endotoxin) is a structural component of the gram-negative outer membrane. The lipid A moiety of LPS binds to the LPS receptor complex expressed by leukocytes, endothelial cells, and parenchymal cells and is the primary component of gram-negative bacteria that is recognized by the immune system. Activation of the LPS receptor complex by native lipid A induces robust cytokine production, leukocyte activation, and inflammation, which is beneficial for clearing bacterial infections at the local level but can cause severe systemic inflammation and shock at higher challenge doses. Interestingly, prior exposure to LPS renders the host resistant to shock caused by subsequent LPS challenge, a phenomenon known as endotoxin tolerance. Treatment with lipid A has also been shown to augment the host response to infection and to serve as a potent vaccine adjuvant. However, the adverse effects associated with the pronounced inflammatory response limit the use of native lipid A as a clinical immunomodulator. More recently, analogs of lipid A have been developed that possess attenuated proinflammatory activity but retain attractive immunomodulatory properties. The lipid A analog monophosphoryl lipid A exhibits approximately 1/1,000th of the toxicity of native lipid A but retains potent immunoadjuvant activity. As such, monophosphoryl lipid A is currently used as an adjuvant in several human vaccine preparations. Because of the potency of lipid A analogs as immunoadjuvants, numerous laboratories are actively working to identify and develop new lipid A mimetics and to optimize their efficacy and safety. Based on those characteristics, lipid A analogs represent an attractive family of immunomodulators.
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Affiliation(s)
- Julia K Bohannon
- *Department of Anesthesiology, Vanderbilt University Medical Center, Nashville, Tennessee; †Department of Anesthesiology, The University of Texas Medical Branch, Galveston, Texas; and ‡School of Medicine, The University of Tennessee Health Science Center, Memphis; and §Department of Pathology, Microbiology and Immunology, Vanderbilt University Medical Center, Nashville, Tennessee
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Villano JS, Rong F, Cooper TK. Bacterial infections in Myd88-deficient mice. Comp Med 2014; 64:110-114. [PMID: 24674585 PMCID: PMC3997288] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2013] [Revised: 09/04/2013] [Accepted: 10/13/2013] [Indexed: 06/03/2023]
Abstract
Three breeding colonies of Myd88(-/-) mice had a history of significant morbidity and mortality. Although strain-specific poor reproductive performance might explain neonatal death and dystocia, mice were found dead or required euthanasia because of moribundity, distended abdomen, head tilt, and seizures. Histopathology results included bacteremia, placentitis, metritis, peritonitis with abscess formation, and suppurative meningoencephalitis. Intralesional gram-negative coccobacilli were present, often in extremely high number. Cultures of samples of the cardiac blood of a mouse and from water-bottle sipper tubes provided to some affected mice grew Pseudomonas aeruginosa. In addition, affected tissues from 2 mice and feces from a third tested PCR-positive for P. aeruginosa. Although the mice had received autoclaved reverse-osmosis-purified drinking water, we suspect that the mice were inoculated with P. aeruginosa through contaminated sipper tubes. Because of the deficiency in most of the Toll-like receptor signaling pathways, these Myd88(-/-) mice were unlikely to have developed competitive innate and adaptive immune responses, resulting in bacterial infections. These clinical cases underscore the importance of understanding how genotype, phenotype and environment affect animal health. Sound husbandry and experimental practices are needed to prevent the exposure of immuno-deficient mice to pathogens.
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Affiliation(s)
- Jason S Villano
- Animal Resources Center, University of Texas Medical Branch, Galveston, Texas, USA; Unit for Laboratory Animal Medicine, University of Michigan Medical School, Ann Arbor, Michigan.
| | - Fang Rong
- Departmen of Pathology, University of Texas Medical Branch, Galveston, Texas
| | - Timothy K Cooper
- Department of Comparative Medicine, Penn State Hershey Medical Center, College of Medicine, Hershey, Pennsylvania
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von Bernuth H, Picard C, Puel A, Casanova JL. Experimental and natural infections in MyD88- and IRAK-4-deficient mice and humans. Eur J Immunol 2013; 42:3126-35. [PMID: 23255009 PMCID: PMC3752658 DOI: 10.1002/eji.201242683] [Citation(s) in RCA: 131] [Impact Index Per Article: 11.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2012] [Revised: 08/11/2012] [Accepted: 10/25/2012] [Indexed: 01/15/2023]
Abstract
Most Toll-like-receptors (TLRs) and interleukin-1 receptors (IL-1Rs) signal via myeloid differentiation primary response 88 (MyD88) and interleukin-1 receptor-associated kinase 4 (IRAK-4). The combined roles of these two receptor families in the course of experimental infections have been assessed in MyD88- and IRAK-4-deficient mice for almost fifteen years. These animals have been shown to be susceptible to 46 pathogens: 27 bacteria, eight viruses, seven parasites, and four fungi. Humans with inborn MyD88 or IRAK-4 deficiency were first identified in 2003. They suffer from naturally occurring life-threatening infections caused by a small number of bacterial species, although the incidence and severity of these infections decrease with age. Mouse TLR- and IL-1R-dependent immunity mediated by MyD88 and IRAK-4 seems to be vital to combat a wide array of experimentally administered pathogens at most ages. By contrast, human TLR- and IL-1R-dependent immunity mediated by MyD88 and IRAK-4 seems to be effective in the natural setting against only a few bacteria and is most important in infancy and early childhood. The roles of TLRs and IL-1Rs in protective immunity deduced from studies in mutant mice subjected to experimental infections should therefore be reconsidered in the light of findings for natural infections in humans carrying mutations as discussed in this review.
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Affiliation(s)
- Horst von Bernuth
- Pediatric Pneumology and Immunology, Charité Hospital - Humboldt University, Berlin, Germany.
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Toll-like receptor 2 deficiency results in impaired antibody responses and septic shock during Borrelia hermsii infection. Infect Immun 2010; 78:4579-88. [PMID: 20696824 DOI: 10.1128/iai.00438-10] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Overwhelming bacteremia is a leading cause of death. To understand the mechanisms involved in protective antibody and pathological inflammatory responses during bacteremia, we have been studying the murine model of Borrelia hermsii infection. Toll-like receptor (TLR) signaling plays an important role in generating the rapid anti-B. hermsii antibody responses required for the resolution of bacteremia. Using NF-κB reporter assays, we found that B. hermsii activates TLR2 and TLR9. However, TLR2(-/-) TLR9(-/-) mice exhibited an impairment in anti-B. hermsii antibody responses similar to that of TLR2(-/-) mice. Moreover, the impairment in the antibody responses of TLR2(-/-) mice or TLR2(-/-) TLR9(-/-) mice coincides with an order-of-magnitude-higher bacteremia, and death results from septic shock, as evidenced by a dysregulated systemic cytokine response and characteristic organ pathology. Since TLR2 appears to be the major extracellular sensor stimulated by B. hermsii, we hypothesized that during elevated bacteremia the activation of intracellular sensors of bacteria triggers dysregulated inflammation in TLR2(-/-) mice. Indeed, blocking the internalization of B. hermsii prevented the induction of inflammatory cytokine responses in TLR2-deficient cells. Furthermore, we found that B. hermsii activates the cytoplasmic sensor nucleotide-binding oligomerization domain 2 (NOD2). Macrophages deficient in both TLR2 and NOD2 have impaired cytokine responses to B. hermsii compared to cells lacking TLR2 alone, and B. hermsii-infected TLR2(-/-) NOD2(-/-) mice exhibited improved survival compared to TLR2(-/-) mice. These data demonstrate that TLR2 is critical for protective immunity and suggest that, during heightened bacteremia, recognition of bacterial components by intracellular sensors can lead to pathological inflammatory responses.
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Sindhava V, Woodman ME, Stevenson B, Bondada S. Interleukin-10 mediated autoregulation of murine B-1 B-cells and its role in Borrelia hermsii infection. PLoS One 2010; 5:e11445. [PMID: 20625435 PMCID: PMC2897882 DOI: 10.1371/journal.pone.0011445] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2010] [Accepted: 06/07/2010] [Indexed: 12/21/2022] Open
Abstract
B cells are typically characterized as positive regulators of the immune response, primarily by producing antibodies. However, recent studies indicate that various subsets of B cells can perform regulatory functions mainly through IL-10 secretion. Here we discovered that peritoneal B-1 (B-1P) cells produce high levels of IL-10 upon stimulation with several Toll-like receptor (TLR) ligands. High levels of IL-10 suppressed B-1P cell proliferation and differentiation response to all TLR ligands studied in an autocrine manner in vitro and in vivo. IL-10 that accumulated in cultures inhibited B-1P cells at second and subsequent cell divisions mainly at the G1/S interphase. IL-10 inhibits TLR induced B-1P cell activation by blocking the classical NF-κB pathway. Co-stimulation with CD40 or BAFF abrogated the IL-10 inhibitory effect on B-1P cells during TLR stimulation. Finally, B-1P cells adoptively transferred from the peritoneal cavity of IL-10−/− mice showed better clearance of Borrelia hermsii than wild-type B-1P cells. This study described a novel autoregulatory property of B-1P cells mediated by B-1P cell derived IL-10, which may affect the function of B-1P cells in infection and autoimmunity.
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Affiliation(s)
- Vishal Sindhava
- Department of Microbiology, Immunology and Molecular Genetics, University of Kentucky College of Medicine, Lexington, Kentucky, United States of America
- Markey Cancer Center, University of Kentucky College of Medicine, Lexington, Kentucky, United States of America
| | - Michael E. Woodman
- Department of Microbiology, Immunology and Molecular Genetics, University of Kentucky College of Medicine, Lexington, Kentucky, United States of America
| | - Brian Stevenson
- Department of Microbiology, Immunology and Molecular Genetics, University of Kentucky College of Medicine, Lexington, Kentucky, United States of America
| | - Subbarao Bondada
- Department of Microbiology, Immunology and Molecular Genetics, University of Kentucky College of Medicine, Lexington, Kentucky, United States of America
- Markey Cancer Center, University of Kentucky College of Medicine, Lexington, Kentucky, United States of America
- * E-mail:
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T-cell-independent immune responses do not require CXC ligand 13-mediated B1 cell migration. Infect Immun 2010; 78:3950-6. [PMID: 20584971 DOI: 10.1128/iai.00371-10] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023] Open
Abstract
The dynamic movement of B cells increases the probability of encountering specific antigen and facilitates cell-cell interactions required for mounting a rapid antibody response. B1a and B1b cells are enriched in the coelomic cavity, contribute to T-cell-independent (TI) antibody responses, and increase in number upon antigen exposure. B1 cell movement is largely governed by Cxc ligand 13 (Cxcl13), and mice deficient in this chemokine have a severe reduction in peritoneal B1 cells. In this study, we examined the role of Cxcl13-dependent B cell migration using Borrelia hermsii infection or intraperitoneal immunization with pneumococcal polysaccharide or 4-hydroxy-3-nitrophenyl-acetyl (NP)-Ficoll, all of which induce robust antibody responses from B1b cells. Surprisingly, we found that antibody responses to B. hermsii or to FhbA, an antigenic target of B1b cells, and the resolution of bacteremia were indistinguishable between wild-type and Cxcl13-/- mice. Importantly, we did not observe an expansion of peritoneal B1b cell numbers in Cxcl13-/- mice. Nonetheless, mice that had resolved infection were resistant to reinfection, indicating that the peritoneal B1b cell reservoir is not required for controlling B. hermsii. Furthermore, despite a reduced peritoneal B1b compartment, immunization with pneumococcal polysaccharide vaccine yielded comparable antigen-specific antibody responses in wild-type and Cxcl13-/- mice and conferred protection against Streptococcus pneumoniae. Likewise, immunization with NP-Ficoll elicited similar antibody responses in wild-type and Cxcl13-/- mice. These data demonstrate that homing of B1 cells into the coelomic cavity is not a requirement for generating protective TI antibody responses, even when antigen is initially localized to this anatomical compartment.
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Petzke MM, Brooks A, Krupna MA, Mordue D, Schwartz I. Recognition of Borrelia burgdorferi, the Lyme disease spirochete, by TLR7 and TLR9 induces a type I IFN response by human immune cells. THE JOURNAL OF IMMUNOLOGY 2009; 183:5279-92. [PMID: 19794067 DOI: 10.4049/jimmunol.0901390] [Citation(s) in RCA: 91] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Borrelia burgdorferi is the spirochetal agent of Lyme disease, a multisystemic disorder characterized by inflammation. Using global transcriptional profiling, we characterized the response of human PBMCs exposed to B. burgdorferi in an ex vivo coculture system. The expression profiles induced by B. burgdorferi were marked by the intense up-regulation of IFN-responsive transcripts and transcripts involved in the JAK/STAT signaling pathway. Transcript levels of IFN-alpha, IFN-beta, and IRF7, and protein concentrations of IFN-alpha, were significantly elevated relative to those in unstimulated PBMCs. The induction of IFN-alpha was completely dependent upon phagocytosis of B. burgdorferi. Addition of a soluble type I IFN receptor, B18R, did not abolish the induction of IFN-inducible genes, indicating that B. burgdorferi directly elicits enhanced expression of these genes independently of type I IFN feedback signaling. Inhibitors of either TLR7 or TLR9 significantly reduced B. burgdorferi-stimulated IFN-alpha protein expression and transcription of IFN-induced genes. Simultaneous inhibition of both TLR7 and TLR9 completely abrogated IFN-alpha induction. The IFN-alpha-producing populations in PBMCs were identified as plasmacytoid dendritic and CD14(+)CD11c(+) cells. These results reveal a TLR7/9-dependent signaling pathway used by human PBMCs to initiate a type I IFN response to the extracellular bacterium B. burgdorferi.
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Affiliation(s)
- Mary M Petzke
- Department of Microbiology and Immunology, New York Medical College, Valhalla, NY 10595, USA.
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Chassin C, Picardeau M, Goujon JM, Bourhy P, Quellard N, Darche S, Badell E, d'Andon MF, Winter N, Lacroix-Lamandé S, Buzoni-Gatel D, Vandewalle A, Werts C. TLR4- and TLR2-Mediated B Cell Responses Control the Clearance of the Bacterial Pathogen,Leptospira interrogans. THE JOURNAL OF IMMUNOLOGY 2009; 183:2669-77. [DOI: 10.4049/jimmunol.0900506] [Citation(s) in RCA: 103] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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Woodman ME, Cooley AE, Avdiushko R, Bowman A, Botto M, Wooten RM, van Rooijen N, Cohen DA, Stevenson B. Roles for phagocytic cells and complement in controlling relapsing fever infection. J Leukoc Biol 2009; 86:727-36. [PMID: 19458267 DOI: 10.1189/jlb.0309169] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
Relapsing fever spirochetes, such as Borrelia hermsii, proliferate to high levels in their hosts' bloodstream until production of IgM against borrelial surface proteins promotes bacterial clearance. The mechanisms by which B. hermsii survives in host blood, as well as the immune mediators that control this infection, remain largely unknown. It has been hypothesized that B. hermsii is naturally resistant to killing by the alternative pathway of complement activation as a result of its ability to bind factor H, a host complement regulator. However, we found that Cfh(-/-) mice were infected to levels identical to those seen in wild-type mice. Moreover, only a small minority of B. hermsii in the blood of wild-type mice had detectable levels of factor H adhered to their outer surfaces. In vitro, complement was found to play a statistically significant role in antibody-mediated inactivation of B. hermsii, although in vivo studies indicated that complement is not essential for host control of B. hermsii. Depletion of mphi and DC from mice had significant impacts on B. hermsii infection, and depleted mice were unable to control bloodstream infections, leading to death. Infection studies using muMT indicated a significant antibody-independent role for mphi and/or DC in host control of relapsing fever infection. Together, these findings indicate mphi and/or DC play a critical role in the production of B. hermsii-specific IgM and for antibody-independent control of spirochete levels.
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Affiliation(s)
- Michael E Woodman
- Department of Microbiology, Immunology, and Molecular Genetics, University of Kentucky College of Medicine, Lexington, KY 40536-0298, USA
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Abstract
Relapsing fever (RF) is a spirochetal infection characterized by periods of sickness with fever at time of high bacteremia that alternate with afebrile periods of relative well being during low bacteremia. Patients with epidemic RF who are doing relatively well have extraordinarily high levels of interleukin-10 (IL-10) in the circulation. We investigated the possibility that IL-10 plays an important protective role in this infection using wild-type and IL-10-deficient mice inoculated with virulent serotype 2 of the RF spirochete Borrelia turicatae. During peak bacteremia there was increased systemic production of IL-10 that quickly resolved in the postpeak period; in contrast, IL-6 and CXCL13 production increased during the peak but remained elevated during postpeak bacteremia. IL-10 deficiency resulted in lower bacteremia, increased specific antibody production, higher production of CXCL13 and IL-6, and thrombotic and hemorrhagic complications affecting multiple organs with secondary tissue injury. Our results revealed that production of IL-10 is highly regulated during RF and plays an important protective role in the prevention of hemorrhagic and thrombotic complications at the cost of reduced pathogen control.
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The Important and Diverse Roles of Antibodies in the Host Response to Borrelia Infections. Curr Top Microbiol Immunol 2008; 319:63-103. [DOI: 10.1007/978-3-540-73900-5_4] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
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Alugupalli KR, Akira S, Lien E, Leong JM. MyD88- and Bruton's tyrosine kinase-mediated signals are essential for T cell-independent pathogen-specific IgM responses. THE JOURNAL OF IMMUNOLOGY 2007; 178:3740-9. [PMID: 17339472 DOI: 10.4049/jimmunol.178.6.3740] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Bacteremia is one of the leading causes of death by infectious disease. To understand the immune mechanisms required for the rapid control of bacteremia, we studied Borrelia hermsii, a bacterial pathogen that colonizes the blood stream of humans and rodents to an extremely high density. A T cell-independent IgM response is essential and sufficient for controlling B. hermsii bacteremia. Mice deficient in Bruton's tyrosine kinase (Btk), despite their known defect in BCR signaling, generated B. hermsii-specific IgM and resolved bacteremia, suggesting that an alternative activation or costimulatory pathway remained functional for T cell-independent B cells in Btk(-/-) mice. B. hermsii contains putative ligands for TLRs, and we found that mice deficient in TLR1, TLR2, or the TLR adaptor MyD88 generated anti-B. hermsii IgM with delayed kinetics and suffered more severe episodes of bacteremia. In striking contrast to the anti-B. hermsii IgM response in mice deficient only in Btk, mice deficient in both Btk and MyD88 were entirely incapable of generating B. hermsii-specific Ab or resolving bacteremia. The response to a T cell-dependent model Ag was unaffected in Btk(-/-) x MyD88(-/-) mice. These results suggest that MyD88 specifically promotes T cell-independent BCR signaling and that, in the absence of Btk, this TLR-mediated stimulation is a required component of this signal.
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Affiliation(s)
- Kishore R Alugupalli
- Department of Microbiology and Immunology and Kimmel Cancer Center, Thomas Jefferson University, 233 South 10th Street, Philadelphia, PA 19107, USA.
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