1
|
Werts C. Interaction of Leptospira with the Innate Immune System. Curr Top Microbiol Immunol 2019; 415:163-187. [PMID: 29038956 DOI: 10.1007/82_2017_46] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Innate immunity encompasses immediate host responses that detect and respond to microbes. Besides recognition by the complement system (see the chapter by A. Barbosa, this volume), innate immunity concerns cellular responses. These are triggered through recognition of conserved microbial components (called MAMPs) by pattern recognition receptors (PRRs), leading, through secretion of cytokines, antimicrobial peptides, and immune mediators, to cellular recruitment and phagocytosis. Leptospira spp. are successful zoonotic pathogenic bacteria that obviously overcome the immune system of their hosts. The first part of this chapter summarizes what is known about leptospires recognition and interaction with phagocytes and other innate immune cells, and the second part describes specific interactions of leptospiral MAMPs with PRRs from the TLR and NLR families. On the one hand, pathogenic leptospires appear to escape macrophage and neutrophil phagocytosis. On the other hand, studies about PRR sensing of leptospires remain very limited, but suggest that pathogenic leptospires escape some of the PRRs in a host-specific manner, due to peculiar cell wall specificities or post-translational modifications that may impair their recognition. Further studies are necessary to clarify the mechanisms and consequences of leptospiral escape on phagocytic functions and hopefully give clues to potential therapeutic strategies aimed at restoring the defective activation of PRRs by pathogenic Leptospira spp.
Collapse
Affiliation(s)
- Catherine Werts
- Unité Biologie et Génétique de La Paroi Bactérienne, Institut Pasteur, Paris, France.
| |
Collapse
|
2
|
Nally JE, Wilson-Welder JH, Hornsby RL, Palmer MV, Alt DP. Inbred Rats as a Model to Study Persistent Renal Leptospirosis and Associated Cellular Immune Responsiveness. Front Cell Infect Microbiol 2018; 8:66. [PMID: 29594063 PMCID: PMC5861151 DOI: 10.3389/fcimb.2018.00066] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2018] [Accepted: 02/26/2018] [Indexed: 12/11/2022] Open
Abstract
Pathogenic species of Leptospira cause leptospirosis, a bacterial zoonotic disease with a global distribution affecting over one million people annually. Rats are regarded as one of the most significant reservoir hosts of infection for human disease, and in the absence of clinical signs of infection, excrete large numbers of organisms in their urine. A unique biological equilibrium exists between pathogenic leptospires and reservoir hosts of infection, but surprisingly, little is known concerning the host's cellular immune response that facilitates persistent renal colonization. To address this deficiency, we established and applied an immunocompetent inbred rat model of persistent renal colonization; leptospires were detected in urine of experimentally infected rats by 3 weeks post-infection and remained positive until 8 weeks post-infection. However, there was little, if any, evidence of inflammation in colonized renal tubules. At 8 weeks post-infection, a robust antibody response was detected against lipopolysaccharide and protein outer membrane (OM) components. Purified B and T cells derived from the spleen of infected and non-infected rats proliferated in response to stimulation with 0.5 μg of OM fractions of Leptospira, including CD4+ T cells, which comprised 40% of proliferating cells, compared to 25% in non-infected controls. However, analysis of gene expression did not determine which immunoregulatory pathways were activated. Lymphocytes purified from the lymph node draining the site of colonization, the renal lymph node, also showed an increase in percentage of proliferating B and T cells. However, in contrast to a phenotype of 40% CD4+ T cells in the spleen, the phenotype of proliferating T cells in the renal lymph node comprised 65% CD4+ T cells. These results confirm that the renal lymph node, the local lymphoid organ, is a dominant site containing Leptospira reactive CD4+ T cells and highlight the need to consider the local, vs. systemic, immune responses during renal colonization infection. The use of inbred immunocompetent rats provides a novel tool to further elucidate those pathophysiological pathways that facilitate the unique biological equilibrium observed in reservoir hosts of leptospirosis.
Collapse
Affiliation(s)
- Jarlath E Nally
- Infectious Bacterial Diseases Research Unit, National Animal Disease Center, Agricultural Research Service, United States Department of Agriculture, Ames, IA, United States
| | - Jennifer H Wilson-Welder
- Infectious Bacterial Diseases Research Unit, National Animal Disease Center, Agricultural Research Service, United States Department of Agriculture, Ames, IA, United States
| | - Richard L Hornsby
- Infectious Bacterial Diseases Research Unit, National Animal Disease Center, Agricultural Research Service, United States Department of Agriculture, Ames, IA, United States
| | - Mitchell V Palmer
- Infectious Bacterial Diseases Research Unit, National Animal Disease Center, Agricultural Research Service, United States Department of Agriculture, Ames, IA, United States
| | - David P Alt
- Infectious Bacterial Diseases Research Unit, National Animal Disease Center, Agricultural Research Service, United States Department of Agriculture, Ames, IA, United States
| |
Collapse
|
3
|
Abstract
PURPOSE OF REVIEW The definitive diagnosis of leptospirosis, which results from infection with spirochetes of the genus Leptospira, currently relies on the use of culture, serological testing (microscopic agglutination testing), and molecular detection. The purpose of this review is to describe new molecular diagnostics for Leptospira and discuss advancements in the use of available methods. RECENT FINDINGS Efforts have been focused on improving the clinical sensitivity of Leptospira detection using molecular methods. In this review, we describe a reoptimized pathogenic species-specific real-time PCR (targeting lipL32) that has demonstrated improved sensitivity, findings by two groups that real-time reverse-transcription PCR assays targeting the 16S rrs gene can improve detection, and two new loop-mediated amplification techniques. Quantitation of leptospiremia, detection in different specimen types, and the complementary roles played by molecular detection and microscopic agglutination testing will be discussed. Finally, a protocol for Leptospira strain subtyping using variable number tandem repeat targets and high-resolution melting will be described. SUMMARY Molecular diagnostics have an established role for the diagnosis of leptospirosis and provide an actionable diagnosis in the acute setting. The use of real-time reverse-transcription PCR for testing serum/plasma and cerebrospinal fluid, when available, may improve the detection of Leptospira without decreasing clinical specificity.
Collapse
|
4
|
Raffray L, Giry C, Thirapathi Y, Reboux AH, Jaffar-Bandjee MC, Gasque P. Increased levels of soluble forms of E-selectin and ICAM-1 adhesion molecules during human leptospirosis. PLoS One 2017; 12:e0180474. [PMID: 28686648 PMCID: PMC5501535 DOI: 10.1371/journal.pone.0180474] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2017] [Accepted: 06/15/2017] [Indexed: 01/09/2023] Open
Abstract
Leptospirosis is a multisystemic zoonotic disease with infiltration of visceral organs by Leptospira. The capacity of the vascular endothelium to grant immune cell recruitment and activation in target organs during the disease course remains poorly characterized. We ascertained the levels of expression of several soluble cell adhesion molecules (CAM) notably expressed by endothelial cells in human leptospirosis. We prospectively enrolled 20 hospitalized patients and compared them to 10 healthy controls. Disease severity was defined by one or more organ failures, or death. Plasmatic concentrations of soluble CAM were assessed by multiplex bead assay at the time of patient presentation (M0) and 1 month after hospital discharge. The levels of soluble E-selectin (sCD62E) and soluble intercellular adhesion molecule 1 (sICAM-1, sCD53) were significantly increased in patients compared to controls (p<0.0001) and at 1 month (p<0.0001) with median values at 978 ng/ml (interquartile ranges 787–1164; sCD62E) and 1021 ng/ml (690–1428; sCD53). At M0, Soluble P-selectin level (sCD62P) was found to be decreased with levels at 60 ng/ml (0–631) versus 711 ng/ml (343–1113) for healthy controls (p<0.05). Levels of sICAM-3 (sCD50), sVCAM-1 (vascular cell adhesion molecule, sCD106) and sPECAM-1 (platelet endothelial cell adhesion molecule, sCD31) were not different from healthy subjects at M0. This study shows that two adhesion molecules, shed as soluble forms, are elevated during the acute phase of leptospirosis: E-selectin and s-ICAM1. These molecules may interfere with the process of immune cell recruitment to clear Leptospira at tissue levels.
Collapse
Affiliation(s)
- Loic Raffray
- Université de La Réunion, CNRS 9192, INSERM U1187, IRD 249, CHU de La Réunion, UMR PIMIT Unité Mixte Processus Infectieux en Milieu Insulaire Tropical, Plateforme Technologique CYROI, Sainte-Clotilde, La Réunion, France
- Laboratoire de Biologie, CHU La Réunion site Félix Guyon, St Denis, La Réunion, France
- Internal Medicine Unit, CHU La Réunion site Félix Guyon, St Denis, La Réunion, France
- * E-mail: (LR); (PG)
| | - Claude Giry
- Microbiology/Virology Laboratory, CHU La Réunion site Félix Guyon, St Denis, La Réunion, France
| | - Yoga Thirapathi
- Internal Medicine Unit, GHER Hospital, St Benoit, La Réunion, France
| | - Anne-Hélène Reboux
- Nephrology Dialysis and Transplantation Unit, CHU La Réunion site Félix Guyon, St Denis, La Réunion, France
| | - Marie-Christine Jaffar-Bandjee
- Université de La Réunion, CNRS 9192, INSERM U1187, IRD 249, CHU de La Réunion, UMR PIMIT Unité Mixte Processus Infectieux en Milieu Insulaire Tropical, Plateforme Technologique CYROI, Sainte-Clotilde, La Réunion, France
- Microbiology/Virology Laboratory, CHU La Réunion site Félix Guyon, St Denis, La Réunion, France
| | - Philippe Gasque
- Université de La Réunion, CNRS 9192, INSERM U1187, IRD 249, CHU de La Réunion, UMR PIMIT Unité Mixte Processus Infectieux en Milieu Insulaire Tropical, Plateforme Technologique CYROI, Sainte-Clotilde, La Réunion, France
- Laboratoire de Biologie, CHU La Réunion site Félix Guyon, St Denis, La Réunion, France
- * E-mail: (LR); (PG)
| |
Collapse
|
5
|
Raffray L, Giry C, Vandroux D, Kuli B, Randrianjohany A, Pequin AM, Renou F, Jaffar-Bandjee MC, Gasque P. Major Neutrophilia Observed in Acute Phase of Human Leptospirosis Is Not Associated with Increased Expression of Granulocyte Cell Activation Markers. PLoS One 2016; 11:e0165716. [PMID: 27802348 PMCID: PMC5089758 DOI: 10.1371/journal.pone.0165716] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2016] [Accepted: 10/17/2016] [Indexed: 01/13/2023] Open
Abstract
It has long been known that pathogenic Leptospira can mobilize the immune system but the specific contribution of neutrophils to control the infectious challenge remains to be clarified. We herein analyzed the phenotype of circulating neutrophils of patients with leptospirosis and healthy controls for the expression of toll-like receptor (TLR) type 2 (TLR2, to sense the leptospiral LPS) and several activation markers: interleukin 8 chemokine receptor CD182 (CXCR2), CD11b of the integrin/opsonin complement receptor type 3 (CR3) and CD15 (ligand of the selectin). The plasmatic level of the main CD182 ligand, interleukin 8 (CXCL8), was measured by ELISA. Hospitalized leptospirosis cases showed marked neutrophilia, particularly in the most severe cases. Interestingly, TLR2 was significantly increased in leptospirosis but identical levels of CD182 and CD11b were detected when compared to controls. CD15 was significantly decreased on neutrophils in leptospirosis but returned to normal within 1 month. Basal levels of IL-8 were measured in control subjects and were not increased in leptospirosis cases at the initial stage of the disease. In conclusion, we observed that neutrophils failed to regulate the expression of several of the receptors involved in cell activation and recruitment. This study further emphasizes the paradigm that neutrophils may be impaired in their overall capacity to thwart bacterial infection in leptospirosis patients.
Collapse
Affiliation(s)
- Loic Raffray
- Université de La Réunion, CNRS 9192, INSERM U1187, IRD 249, CHU de La Réunion, Unité Mixte Processus Infectieux en Milieu Insulaire Tropical (PIMIT), Plateforme Technologique CYROI, Sainte-Clotilde, La Réunion, France
- Laboratoire d’immunologie clinique et expérimentale ZOI (LICE OI), CHU La Réunion site Félix Guyon, St Denis, La Réunion, France
- Internal Medicine Unit, CHU La Réunion site Félix Guyon, St Denis, La Réunion, France
- * E-mail:
| | - Claude Giry
- Université de La Réunion, CNRS 9192, INSERM U1187, IRD 249, CHU de La Réunion, Unité Mixte Processus Infectieux en Milieu Insulaire Tropical (PIMIT), Plateforme Technologique CYROI, Sainte-Clotilde, La Réunion, France
- Microbiology/Virology Laboratory, CHU La Réunion site Félix Guyon, St Denis, La Réunion, France
| | - David Vandroux
- Intensive Care Unit, CHU La Réunion site Félix Guyon, St Denis, La Réunion, France
| | - Barbara Kuli
- Infectious Diseases Unit, CHU La Réunion site Félix Guyon, St Denis, La Réunion, France
| | | | - Anne-Marie Pequin
- Hematology laboratory, CHU La Réunion site Félix Guyon, St Denis, La Réunion, France
| | - Frédéric Renou
- Internal Medicine Unit, CHU La Réunion site Félix Guyon, St Denis, La Réunion, France
| | - Marie-Christine Jaffar-Bandjee
- Université de La Réunion, CNRS 9192, INSERM U1187, IRD 249, CHU de La Réunion, Unité Mixte Processus Infectieux en Milieu Insulaire Tropical (PIMIT), Plateforme Technologique CYROI, Sainte-Clotilde, La Réunion, France
- Microbiology/Virology Laboratory, CHU La Réunion site Félix Guyon, St Denis, La Réunion, France
| | - Philippe Gasque
- Université de La Réunion, CNRS 9192, INSERM U1187, IRD 249, CHU de La Réunion, Unité Mixte Processus Infectieux en Milieu Insulaire Tropical (PIMIT), Plateforme Technologique CYROI, Sainte-Clotilde, La Réunion, France
- Laboratoire d’immunologie clinique et expérimentale ZOI (LICE OI), CHU La Réunion site Félix Guyon, St Denis, La Réunion, France
| |
Collapse
|