Publications by authors named "Nathalie Winter"

39 Publications

Neutrophils Encompass a Regulatory Subset Suppressing T Cells in Apparently Healthy Cattle and Mice.

Front Immunol 2021 26;12:625244. Epub 2021 Feb 26.

INRAE, Université de Tours, ISP, Nouzilly, France.

Neutrophils that reside in the bone marrow are swiftly recruited from circulating blood to fight infections. For a long time, these first line defenders were considered as microbe killers. However their role is far more complex as cross talk with T cells or dendritic cells have been described for human or mouse neutrophils. In cattle, these new roles are not documented yet. We identified a new subset of regulatory neutrophils that is present in the mouse bone marrow or circulate in cattle blood under steady state conditions. These regulatory neutrophils that display MHC-II on the surface are morphologically indistinguishable from classical MHC-II neutrophils. However MHC-II and MHC-II neutrophils display distinct transcriptomic profiles. While MHC-II and MHC-II neutrophils display similar bacterial phagocytosis or killing activity, MHC-II only are able to suppress T cell proliferation under contact-dependent mechanisms. Regulatory neutrophils are highly enriched in lymphoid organs as compared to their MHC-II counterparts and in the mouse they express PDL-1, an immune checkpoint involved in T-cell blockade. Our results emphasize neutrophils as true partners of the adaptive immune response, including in domestic species. They open the way for discovery of new biomarkers and therapeutic interventions to better control cattle diseases.
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http://dx.doi.org/10.3389/fimmu.2021.625244DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7952614PMC
February 2021

Isolation of Bovine Neutrophils by Fluorescence- and Magnetic-Activated Cell Sorting.

Methods Mol Biol 2021 ;2236:203-217

INRAE, Univ Tours, ISP, Nouzilly, France.

Flow cytometry and magnetic bead technology enable the separation of cell populations with the highest degree of purity. Here, we describe protocols to sort bovine neutrophils from blood, the labeling and sorting, including gating strategies. We also provide advice to preserve neutrophil viability and detail a protocol to measure phagocytosis and oxidative species production.
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http://dx.doi.org/10.1007/978-1-0716-1060-2_16DOI Listing
March 2021

CR3 Engaged by PGL-I Triggers Syk-Calcineurin-NFATc to Rewire the Innate Immune Response in Leprosy.

Front Immunol 2019 17;10:2913. Epub 2019 Dec 17.

ISP, Infectiologie et Santé Publique, INRA, Université de Tours, Nouzilly, France.

, the causative agent of leprosy, is unique amongst human pathogens in its capacity to produce the virulence factor phenolic glycolipid (PGL)-I. In addition to mediating bacterial tropism for neurons, PGL-I interacts with Complement Receptor (CR)3 on macrophages (MPs) to promote infection. We demonstrate here that PGL-I binding to CR3 also enhances bacterial invasion of both polymorphonuclear neutrophils (PMNs) and dendritic cells (DCs). Moreover, in all cell types CR3 engagement by PGL-I activates the Syk tyrosine kinase, inducing calcineurin-dependent nuclear translocation of the transcription factor NFATc. This selectively augments the production of IL-2 by DCs, IL-10 by PMNs and IL-1β by MPs. In intranasally-infected mice PGL-I binding to CR3 heightens mycobacterial phagocytosis by lung PMNs and MPs, and stimulates NFATc-controlled production of Syk-dependent cytokines. Our study thus identifies the CR3-Syk-NFATc axis as a novel signaling pathway activated by PGL-I in innate immune cells, rewiring host cytokine responses to .
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http://dx.doi.org/10.3389/fimmu.2019.02913DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6928039PMC
November 2020

CFTR-deficient pigs display alterations of bone microarchitecture and composition at birth.

J Cyst Fibros 2020 05 29;19(3):466-475. Epub 2019 Nov 29.

Université de Reims Champagne Ardenne, BIOS EA 4691, Biomatériaux et Inflammation en site osseux, SFR CAP-Santé (FED 4231), 1, Avenue du Maréchal Juin, 51097 Reims, France. Electronic address:

Background: The lack of cystic fibrosis transmembrane conductance regulator (CFTR) function causes cystic fibrosis (CF), predisposing to severe lung disease, reduced growth and osteopenia. Both reduced bone content and strength are increasingly recognized in infants with CF before the onset of significant lung disease, suggesting a developmental origin and a possible role in bone disease pathogenesis. The role of CFTR in bone metabolism is unclear and studies on humans are not feasible. Deletion of CFTR in pigs (CFTR pigs) displays at birth severe malformations similar to humans in the intestine, respiratory tract, pancreas, liver, and male reproductive tract.

Methods: We compared bone parameters of CFTR male and female pigs with those of their wild-type (WT) littermates at birth. Morphological and microstructural properties of femoral cortical and trabecular bone were evaluated using micro-computed tomography (μCT), and their chemical compositions were examined using Raman microspectroscopy.

Results: The integrity of the CFTR bone was altered due to changes in its microstructure and chemical composition in both sexes. Low cortical thickness and high cortical porosity were found in CFTR pigs compared to sex-matched WT littermates. Moreover, an increased chemical composition heterogeneity associated with higher carbonate/phosphate ratio and higher mineral crystallinity was found in CFTR trabecular bone, but not in CFTR cortical bone.

Conclusions: The loss of CFTR directly alters the bone composition and metabolism of newborn pigs. Based on these findings, we speculate that bone defects in patients with CF could be a primary, rather than a secondary consequence of inflammation and infection.
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http://dx.doi.org/10.1016/j.jcf.2019.10.023DOI Listing
May 2020

Neutrophils and Close Relatives in the Hypoxic Environment of the Tuberculous Granuloma: New Avenues for Host-Directed Therapies?

Front Immunol 2019 12;10:417. Epub 2019 Mar 12.

INRA, Universite de Tours, UMR Infectiologie et Sante Publique, Nouzilly, France.

Tuberculosis (TB), caused by (Mtb) is one of the most prevalent lung infections of humans and kills ~1.7 million people each year. TB pathophysiology is complex with a central role played by granuloma where a delicate balance takes place to both constrain bacilli and prevent excessive inflammation that may destroy lung functions. Neutrophils reach the lung in waves following first encounter with bacilli and contribute both to early Mtb elimination and late deleterious inflammation. The hypoxic milieu where cells and bacilli cohabit inside the granuloma favors metabolism changes and the impact on TB infection needs to be more thoroughly understood. At the cellular level while the key role of the alveolar macrophage has long been established, behavior of neutrophils in the hypoxic granuloma remains poorly explored. This review will bring to the front new questions that are now emerging regarding neutrophils activity in TB. Are different neutrophil subsets involved in Mtb infection and how? How do neutrophils and close relatives contribute to shaping the granuloma immune environment? What is the role of hypoxia and hypoxia induced factors inside granuloma on neutrophil fate and functions and TB pathophysiology? Addressing these questions is key to the development of innovative host-directed therapies to fight TB.
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http://dx.doi.org/10.3389/fimmu.2019.00417DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6423059PMC
June 2020

Mycobacterial Phenolic Glycolipids Selectively Disable TRIF-Dependent TLR4 Signaling in Macrophages.

Front Immunol 2018 19;9. Epub 2018 Jan 19.

Unité d'Immunobiologie de l'Infection, INSERM U1221, Institut Pasteur, Paris, France.

Phenolic glycolipids (PGLs) are cell wall components of a subset of pathogenic mycobacteria, with immunomodulatory properties. Here, we show that in addition, PGLs exert antibactericidal activity by limiting the production of nitric oxide synthase (iNOS) in mycobacteria-infected macrophages. PGL-mediated downregulation of iNOS was complement receptor 3-dependent and comparably induced by bacterial and purified PGLs. Using PGL-1 as a model, we found that PGLs dampen the toll-like receptor (TLR)4 signaling pathway, with macrophage exposure to PGLs leading to significant reduction in TIR-domain-containing adapter-inducing interferon-β (TRIF) protein level. PGL-driven decrease in TRIF operated posttranscriptionally and independently of Src-family tyrosine kinases, lysosomal and proteasomal degradation. It resulted in the defective production of TRIF-dependent IFN-β and CXCL10 in TLR4-stimulated macrophages, in addition to iNOS. Our results unravel a mechanism by which PGLs hijack both the bactericidal and inflammatory responses of host macrophages. Moreover, they identify TRIF as a critical node in the crosstalk between CR3 and TLR4.
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http://dx.doi.org/10.3389/fimmu.2018.00002DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5780341PMC
February 2019

Experimental infection of cattle with Mycobacterium tuberculosis isolates shows the attenuation of the human tubercle bacillus for cattle.

Sci Rep 2018 01 17;8(1):894. Epub 2018 Jan 17.

UCD School of Veterinary Medicine, University College Dublin, Dublin, Ireland.

The Mycobacterium tuberculosis complex (MTBC) is the collective term given to the group of bacteria that cause tuberculosis (TB) in mammals. It has been reported that M. tuberculosis H37Rv, a standard reference MTBC strain, is attenuated in cattle compared to Mycobacterium bovis. However, as M. tuberculosis H37Rv was isolated in the early 1930s, and genetic variants are known to exist, we sought to revisit this question of attenuation of M. tuberculosis for cattle by performing a bovine experimental infection with a recent M. tuberculosis isolate. Here we report infection of cattle using M. bovis AF2122/97, M. tuberculosis H37Rv, and M. tuberculosis BTB1558, the latter isolated in 2008 during a TB surveillance project in Ethiopian cattle. We show that both M. tuberculosis strains caused reduced gross pathology and histopathology in cattle compared to M. bovis. Using M. tuberculosis H37Rv and M. bovis AF2122/97 as the extremes in terms of infection outcome, we used RNA-Seq analysis to explore differences in the peripheral response to infection as a route to identify biomarkers of progressive disease in contrast to a more quiescent, latent infection. Our work shows the attenuation of M. tuberculosis strains for cattle, and emphasizes the potential of the bovine model as a 'One Health' approach to inform human TB biomarker development and post-exposure vaccine development.
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http://dx.doi.org/10.1038/s41598-017-18575-5DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5772528PMC
January 2018

The C3HeB/FeJ mouse model recapitulates the hallmark of bovine tuberculosis lung lesions following Mycobacterium bovis aerogenous infection.

Vet Res 2017 11 7;48(1):73. Epub 2017 Nov 7.

INRA, Université de Tours, UMR 1282, Infectiologie et Santé Publique, Nouzilly, France.

Achieving the control of bovine tuberculosis (bTB) would require the discovery of an efficient combined immunodiagnostic and vaccine strategy. Since in vivo experiments on cattle are not ethically and economically acceptable there is a need for a cost-effective animal model capable of reproducing, as closely as possible, the physiopathology of bTB to (i) better characterize the cellular and molecular features of bTB immunopathogenesis and (ii) screen preclinical vaccine candidates. To develop such a model, we focused on the C3HeB/FeJ Kramnik's mouse forming hypoxic, encapsulated granulomas with a caseous necrotic center following Mycobacterium tuberculosis infection. Our work represents the first investigation on C3HeB/FeJ interaction with M. bovis, the main agent of bTB. Detailed histopathological analysis of C3HeB/FeJ lung lesions development following aerogenous M. bovis infection unraveled a bimodal evolution of the pathology. The C3HeB/FeJ recapitulated all the hallmarks of classical bovine lung granulomas but also developed, to some extend, lethal necrotic large lesions characterized by high mycobacterial and neutrophil load, and an inefficient collagen-driven lesion encapsulation. Interestingly these rapidly invasive pneumonia lesions, occurring in a constant percentage of the mice, shared all features with some exacerbated lung lesions that we and others have observed in lungs of cattle naturally or experimentally infected with M. bovis. Together, our findings demonstrate the relevance of the C3HeB/FeJ mouse as a comprehensive model to study bTB immunopathology that could be used for further vaccine therapies in the future.
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http://dx.doi.org/10.1186/s13567-017-0477-7DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5678586PMC
November 2017

Recombinant BCG Expressing LTAK63 Adjuvant induces Superior Protection against Mycobacterium tuberculosis.

Sci Rep 2017 05 18;7(1):2109. Epub 2017 May 18.

Laboratório Especial de Desenvolvimento de Vacinas, Instituto Butantan, São Paulo, SP, Brazil.

In order to develop an improved BCG vaccine against tuberculosis we have taken advantage of the adjuvant properties of a non-toxic derivative of Escherichia coli heat labile enterotoxin (LT), LTAK63. We have constructed rBCG strains expressing LTAK63 at different expression levels. Mice immunized with BCG expressing low levels of LTAK63 (rBCG-LTAK63) showed higher Th1 cytokines and IL-17 in the lungs, and when challenged intratracheally with Mycobacterium tuberculosis displayed a 2.0-3.0 log reduction in CFU as compared to wild type BCG. Histopathological analysis of lung tissues from protected mice revealed a reduced inflammatory response. Immunization with rBCG-LTAK63 also protected against a 100-fold higher challenge dose. Mice immunized with rBCG-LTAK63 produced an increase in TGF-β as compared with BCG after challenge, with a corresponding reduction in Th1 and Th17 cytokines, as determined by Real Time RT-PCR. Furthermore, rBCG-LTAK63 also displays protection against challenge with a highly virulent Beijing isolate. Our findings suggest that BCG with low-level expression of the LTAK63 adjuvant induces a stronger immune response in the lungs conferring higher levels of protection, and a novel mechanism subsequently triggers a regulatory immune response, which then limits the pathology. The rBCG-LTAK63 strain can be the basis of an improved vaccine against tuberculosis.
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http://dx.doi.org/10.1038/s41598-017-02003-9DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5437048PMC
May 2017

The Ag85B protein of the BCG vaccine facilitates macrophage uptake but is dispensable for protection against aerosol Mycobacterium tuberculosis infection.

Vaccine 2016 05 6;34(23):2608-15. Epub 2016 Apr 6.

Microbial Pathogenesis and Immunity Group, Discipline of Infectious Diseases and Immunology, University of Sydney, Sydney, NSW, Australia; Mycobacterial Research Group, Centenary Institute of Cancer Medicine and Cell Biology, Sydney, NSW, Australia. Electronic address:

Defining the function and protective capacity of mycobacterial antigens is crucial for progression of tuberculosis (TB) vaccine candidates to clinical trials. The Ag85B protein is expressed by all pathogenic mycobacteria and is a component of multiple TB vaccines under evaluation in humans. In this report we examined the role of the BCG Ag85B protein in host cell interaction and vaccine-induced protection against virulent Mycobacterium tuberculosis infection. Ag85B was required for macrophage infection in vitro, as BCG deficient in Ag85B expression (BCG:(Δ85B)) was less able to infect RAW 264.7 macrophages compared to parental BCG, while an Ag85B-overexpressing BCG strain (BCG:(oex85B)) demonstrated improved uptake. A similar pattern was observed in vivo after intradermal delivery to mice, with significantly less BCG:(Δ85B) present in CD64(hi)CD11b(hi) macrophages compared to BCG or BCG:(oex85B). After vaccination of mice with BCG:(Δ85B) or parental BCG and subsequent aerosol M. tuberculosis challenge, similar numbers of activated CD4(+) and CD8(+) T cells were detected in the lungs of infected mice for both groups, suggesting the reduced macrophage uptake observed by BCG:(Δ85B) did not alter host immunity. Further, vaccination with both BCG:(Δ85B) and parental BCG resulted in a comparable reduction in pulmonary M. tuberculosis load. These data reveal an unappreciated role for Ag85B in the interaction of mycobacteria with host cells and indicates that single protective antigens are dispensable for protective immunity induced by BCG.
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http://dx.doi.org/10.1016/j.vaccine.2016.03.089DOI Listing
May 2016

IL-17RA in Non-Hematopoietic Cells Controls CXCL-1 and 5 Critical to Recruit Neutrophils to the Lung of Mycobacteria-Infected Mice during the Adaptive Immune Response.

PLoS One 2016 12;11(2):e0149455. Epub 2016 Feb 12.

INRA, Université de Tours, UMR 1282, Infectiologie et Santé Publique, Nouzilly, France.

During chronic infection with Mycobacterium tuberculosis (Mtb), bacilli multiplication is constrained within lung granulomas until excessive inflammation destroys the lung. Neutrophils are recruited early and participate in granuloma formation, but excessive neutrophilia exacerbates the tuberculosis disease. Neutrophils thus appear as potential targets for therapeutic interventions, especially in patients for whom no antibiotic treatment is possible. Signals that regulate neutrophil recruitment to the lung during mycobacterial infection need to be better understood. We demonstrated here, in the mouse model, that neutrophils were recruited to the lung in two waves after intranasal infection with virulent Mtb or the live attenuated vaccine strain Bacillus Calmette Guérin (BCG). A first wave of neutrophils was swiftly recruited, followed by a subsequent adaptive wave that reached the lung together with IFN-γ- and IL-17A-producing T cells. Interestingly, the second neutrophil wave did not participate to mycobacteria control in the lung and established contacts with T cells. The adaptive wave was critically dependent on the expression of IL-17RA, the receptor for IL-17A, expressed in non-hematopoietic cells. In absence of this receptor, curtailed CXCL-1 and 5 production in the lung restrained neutrophil recruitment. CXCL-1 and 5 instillation reconstituted lung neutrophil recruitment in BCG-infected IL17RA-/- mice.
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http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0149455PLOS
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4752258PMC
July 2016

IL-17A Is an Important Effector of the Immune Response of the Mammary Gland to Escherichia coli Infection.

J Immunol 2016 Jan 18;196(2):803-12. Epub 2015 Dec 18.

UMR1282 Infectiologie et Santé Publique, Institut National de la Recherche Agronomique, F-37380 Nouzilly, France; and UMR1282 Infectiologie et Santé Publique, Université François-Rabelais de Tours, F-37000 Tours, France

The cytokine IL-17A has been shown to play critical roles in host defense against bacterial and fungal infections at different epithelial sites, but its role in the defense of the mammary gland (MG) has seldom been investigated, although infections of the MG constitute the main pathology afflicting dairy cows. In this study, we showed that IL-17A contributes to the defense of the MG against Escherichia coli infection by using a mouse mastitis model. After inoculation of the MG with a mastitis-causing E. coli strain, the bacterial load increased rapidly, triggering an intense influx of leukocytes into mammary tissue and increased concentrations of IL-6, IL-22, TNF-α, and IL-10. Neutrophils were the first cells that migrated intensely to the mammary tissue, in line with an early production of CXCL2. Depletion of neutrophils induced an increased mammary bacterial load. There was a significant increase of IL-17-containing CD4(+) αβ T lymphocyte numbers in infected glands. Depletion of IL-17A correlated with an increased bacterial colonization and IL-10 production. Intramammary infusion of IL-17A at the onset of infection was associated with markedly decreased bacterial numbers, decreased IL-10 production, and increased neutrophil recruitment. Depletion of CD25(+) regulatory T cells correlated with a decreased production of IL-10 and a reduced bacterial load. These results indicate that IL-17A is an important effector of MG immunity to E. coli and suggest that an early increased local production of IL-17A would improve the outcome of infection. These findings point to a new lead to the development of vaccines against mastitis.
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http://dx.doi.org/10.4049/jimmunol.1500705DOI Listing
January 2016

Interferon gamma response to Mycobacterium avium subsp. paratuberculosis specific lipopentapeptide antigen L5P in cattle.

Res Vet Sci 2015 Oct 1;102:118-21. Epub 2015 Aug 1.

UMR1282, Infectiologie et Santé Publique (ISP-311), INRA Centre Val de Loire, F-37380 Nouzilly, France. Electronic address:

After Mycobacterium avium subsp. paratuberculosis (Map) infection the cell-mediated immune (CMI) response indicative of early Th1 activation may be detected using interferon-gamma release assay (IGRA). Currently, the purified protein derivatives (PPDs), i.e., the total extract of mycobacteria antigens are used to recall CMI responses against Map. This study aimed to assess the ability of the chemically synthesized Map specific cell wall lipopentapeptide L5P to induce CMI response in cows infected by Map compared to PPD. L5P and PPD elicited an IFN-γ response in 12 and 35 animals from two Map infected herds respectively, but IFN-γ was not detected in the 13 cows recruited from a non-infected herd. Levels of IFN-γ detected were higher with PPD than with L5P. There was no correlation between the IFN-γ response and the humoral response to Map or faecal culture.
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http://dx.doi.org/10.1016/j.rvsc.2015.07.017DOI Listing
October 2015

Mycobacteria-infected dendritic cells attract neutrophils that produce IL-10 and specifically shut down Th17 CD4 T cells through their IL-10 receptor.

J Immunol 2013 Oct 30;191(7):3818-26. Epub 2013 Aug 30.

Institut National de la Recherche Agronomique, Université de Tours, Unité Mixte de Recherches 1282, Infectiologie et Santé Publique, 37380 Nouzilly, France.

Neutrophils participate in the control of mycobacterial infection both by directly eliminating bacilli and by interacting with macrophages and dendritic cells (DCs). Despite host defenses, slow-growing mycobacteria can persist in the host for decades, mostly inside macrophages and DCs, and eventually destroy tissues after exacerbated inflammation. IL-17A-driven neutrophil recruitment may participate in this process. We report that mouse bone marrow-derived DCs infected with live Mycobacterium bovis Bacillus Calmette-Guérin (BCG) produced large amounts of CXCL1 and CXCL2, and attracted neutrophils. After physical contact with DCs infected with live BCG, the neutrophils produced large quantities of the immunosuppressive cytokine IL-10 via the MyD88 and spleen tyrosine kinase pathways. The CD11b integrin was involved in this neutrophil-DC interaction and allowed IL-10 production. TCR OVA transgenic mice immunized with a BCG strain producing OVA mounted an OVA-specific Th17 and Th1 CD4 response. Interestingly, IL-10-producing neutrophils specifically shut down IL-17A production by Th17 CD4 cells, but not IFN-γ production by Th1 cells. This was due to Th17 CD4 cell-restricted expression of the receptor for IL-10. After neutrophil depletion, total mouse lung cells produced less IL-10 but more IL-17A; IFN-γ production was not affected. Therefore, we suggest that during mycobacterial infection, regulatory neutrophils are instructed by infected reservoir DCs to produce IL-10 that specifically targets IL-10Rα-expressing Th17 CD4 T cells. This could be important to control the otherwise exuberant Th17 response.
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http://dx.doi.org/10.4049/jimmunol.1300527DOI Listing
October 2013

The pig as a model for investigating the role of neutrophil serine proteases in human inflammatory lung diseases.

Biochem J 2012 Nov;447(3):363-70

Université François Rabelais, UMR 1100, F-37032 Tours, France.

The serine proteases released by activated polymorphonuclear neutrophils [NSPs (neutrophil serine proteases)] contribute to a variety of inflammatory lung diseases, including CF (cystic fibrosis). They are therefore key targets for the development of efficient inhibitors. Although rodent models have contributed to our understanding of several diseases, we have previously shown that they are not appropriate for testing anti-NSP therapeutic strategies [Kalupov, Brillard-Bourdet, Dade, Serrano, Wartelle, Guyot, Juliano, Moreau, Belaaouaj and Gauthier (2009) J. Biol. Chem. 284, 34084-34091). Thus NSPs must be characterized in an animal model that is much more likely to predict how therapies will act in humans in order to develop protease inhibitors as drugs. The recently developed CFTR-/- (CFTR is CF transmembrane conductance regulator) pig model is a promising alternative to the mouse model of CF [Rogers, Stoltz, Meyerholz, Ostedgaard, Rokhlina, Taft, Rogan, Pezzulo, Karp, Itani et al. (2008) Science 321, 1837-1841]. We have isolated blood neutrophils from healthy pigs and determined their responses to the bacterial pathogens Pseudomonas aeruginosa and Staphylococcus aureus, and the biochemical properties of their NSPs. We used confocal microscopy and antibodies directed against their human homologues to show that the three NSPs (elastase, protease 3 and cathepsin G) are enzymatically active and present on the surface of triggered neutrophils and NETs (neutrophil extracellular traps). All of the porcine NSPs are effectively inhibited by human NSP inhibitors. We conclude that there is a close functional resemblance between porcine and human NSPs. The pig is therefore a suitable animal model for testing new NSP inhibitors as anti-inflammatory agents in neutrophil-associated diseases such as CF.
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http://dx.doi.org/10.1042/BJ20120818DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3492928PMC
November 2012

An isoniazid analogue promotes Mycobacterium tuberculosis-nanoparticle interactions and enhances bacterial killing by macrophages.

Antimicrob Agents Chemother 2012 May 13;56(5):2259-67. Epub 2012 Feb 13.

Laboratory of Immunobiology, Department of Microbiology, Immunology and Parasitology, Universidade Federal de Santa Catarina, Florianopolis, Brazil.

Nanoenabled drug delivery systems against tuberculosis (TB) are thought to control pathogen replication by targeting antibiotics to infected tissues and phagocytes. However, whether nanoparticle (NP)-based carriers directly interact with Mycobacterium tuberculosis and how such drug delivery systems induce intracellular bacterial killing by macrophages is not defined. In the present study, we demonstrated that a highly hydrophobic citral-derived isoniazid analogue, termed JVA, significantly increases nanoencapsulation and inhibits M. tuberculosis growth by enhancing intracellular drug bioavailability. Importantly, confocal and atomic force microscopy analyses revealed that JVA-NPs associate with both intracellular M. tuberculosis and cell-free bacteria, indicating that NPs directly interact with the bacterium. Taken together, these data reveal a nanotechnology-based strategy that promotes antibiotic targeting into replicating extra- and intracellular mycobacteria, which could actively enhance chemotherapy during active TB.
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http://dx.doi.org/10.1128/AAC.05993-11DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3346657PMC
May 2012

Oral delivery of BCG Moreau Rio de Janeiro gives equivalent protection against tuberculosis but with reduced pathology compared to parenteral BCG Danish vaccination.

Vaccine 2010 Oct 12;28(43):7109-16. Epub 2010 Aug 12.

Centre for Emergency Preparedness and Response, Health Protection Agency, Porton Down, Salisbury, Wiltshire SP4 0JG, UK.

There is a need for an improved vaccine to better control human tuberculosis (TB), as the only currently available TB vaccine, bacillus Calmette-Guerin (BCG) delivered parenterally, offers variable levels of efficacy. Therefore, recombinant strains expressing additional antigens are being developed alongside alternative routes to parenteral delivery. There is strong evidence that BCG Moreau (RdJ) is a safe and effective vaccine in humans when given by the oral route. This study compared the efficacy of a single oral dose of wild type BCG Moreau Rio de Janeiro (RdJ), or a recombinant RdJ strain expressing Ag85B-ESAT6 fusion protein, formulated with and without lipid to enhance oral delivery, with subcutaneous BCG Danish 1331 and saline control groups in a guinea pig aerosol infection model of pulmonary tuberculosis. Protection was measured as survival at 30 weeks post-challenge and reduced bacterial load and histopathology in lungs and spleen. Results showed that a single oral dose of BCG Moreau (RdJ) or recombinant BCG Moreau (RdJ)-Ag85B-ESAT6, formulated with or without lipid, gave protection equivalent to subcutaneously delivered BCG Danish in the 30 weeks post-challenge survival study. The orally delivered vaccines gave reduced pathology scores in the lungs (three of the four formulations) and spleens (all four formulations) compared to subcutaneously delivered BCG Danish. The oral wild type BCG Moreau (RdJ) in lipid and the unformulated oral wild type BCG Moreau (RdJ) vaccine also gave statistically lower bacterial loads in the lungs and spleens, respectively, compared to subcutaneously delivered BCG Danish. This study provides further evidence to show that lipid formulation does not impair vaccine efficacy and may enhance the delivery and stability of oral vaccines intended for use in countries with poor health infrastructure. Oral delivery also avoids needles (and associated cross-infection risks) and immunisation without the need for specially trained medical professional staff.
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http://dx.doi.org/10.1016/j.vaccine.2010.07.087DOI Listing
October 2010

Mycobacterium bovis bacillus Calmette-Guérin vaccination mobilizes innate myeloid-derived suppressor cells restraining in vivo T cell priming via IL-1R-dependent nitric oxide production.

J Immunol 2010 Feb 18;184(4):2038-47. Epub 2010 Jan 18.

Institut Pasteur Unité Génétique Mycobactérienne, Université Pierre et Marie Curie-Paris 6, AP-HP Groupe Hospitalier Pitié-Salpétrière Service d'Immunologie, Paris, France.

Early immune response to the largely used Mycobacterium bovis bacillus Calmette-Guérin (BCG) intradermal vaccine remains ill defined. Three days after BCG inoculation into the mouse ear, in addition to neutrophils infiltrating skin, we observed CD11b(+)Ly-6C(int)Ly-6G(-) myeloid cells. Neutrophil depletion markedly enhanced their recruitment. These cells differed from inflammatory monocytes and required MyD88-dependent BCG-specific signals to invade skin, whereas neutrophil influx was MyD88 independent. Upon BCG phagocytosis, CD11b(+)Ly-6C(int)Ly-6G(-) cells produced NO, which required the IL-1 receptor. Despite NO production, they were unable to kill BCG or the nonpathogenic Mycobacterium smegmatis. However, they markedly impaired T cell priming in the draining lymph node. Their elimination by all-trans retinoid acid treatment increased the number of IFN-gamma-producing CD4 T cells. Thus, BCG vaccination recruits innate myeloid-derived suppressor cells, akin to mouse tumor-infiltrating cells. These propathogenic cells dampen the early T cell response and might facilitate BCG persistence.
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http://dx.doi.org/10.4049/jimmunol.0903348DOI Listing
February 2010

TLR4- and TLR2-mediated B cell responses control the clearance of the bacterial pathogen, Leptospira interrogans.

J Immunol 2009 Aug 27;183(4):2669-77. Epub 2009 Jul 27.

INSERM, U773, Centre de Recherche Biomédicale Bichat-Beaujon, BP 416 Paris France.

Leptospirosis is a widespread zoonosis caused by pathogenic Leptospira interrogans that are transmitted by asymptomatic infected rodents. Leptospiral lipoproteins and LPS have been shown to stimulate murine cells via TLRs 2 and 4. Host defense mechanisms remain obscure, although TLR4 has been shown to be involved in clearing Leptospira. In this study, we show that double (TLR2 and TLR4) knockout (DKO) mice rapidly died from severe hepatic and renal failure following Leptospira inoculation. Strikingly, the severe proinflammatory response detected in the liver and kidney from Leptospira-infected DKO mice appears to be independent of MyD88, the main adaptor of TLRs. Infection of chimeric mice constructed with wild-type and DKO mice, and infection of several lines of transgenic mice devoid of T and/or B lymphocytes, identified B cells as the crucial lymphocyte subset responsible for the clearance of Leptospira, through the early production of specific TLR4-dependent anti-Leptospira IgMs elicited against the leptospiral LPS. We also found a protective tissue compartmentalized TLR2/TLR4-mediated production of IFN-gamma by B and T lymphocytes, in the liver and kidney, respectively. In contrast, the tissue inflammation observed in Leptospira-infected DKO mice was further characterized to be mostly due to B lymphocytes in the liver and T cells in the kidney. Altogether these findings demonstrate that TLR2 and TLR4 play a key role in the early control of leptospirosis, but do not directly trigger the inflammation induced by pathogenic Leptospira.
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http://dx.doi.org/10.4049/jimmunol.0900506DOI Listing
August 2009

In situ IL-12/23p40 production during mycobacterial infection is sustained by CD11bhigh dendritic cells localized in tissue sites distinct from those harboring bacilli.

J Immunol 2009 Jun;182(11):6915-25

Immunobiology Section, Laboratory of Parasitic Diseases, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD 20892, USA.

Although IL-12/23p40 is known to play a major role in host resistance to Mycobacterium spp, the cellular source, tissue localization, and regulation of p40 production during mycobacterial infection in vivo has been unclear. In this study, we used IL-12/23p40eYFP (yet40) reporter mice to track expression of the cytokine following Mycobacterium bovis bacillus Calmette-Guérin (BCG) infection. We found that in spleens of these mice, p40 production is initiated by a transient burst from CD11b(low)CD11c(+) dendritic cells (DC) which are later replaced at the onset of granuloma formation by CD11b(high)CD11c(+) DC as the major source of the cytokine. The latter subset was also found to be the key producer of DC-derived p40 in nonlymphoid tissue and in both spleen and liver optimal production of the cytokine was regulated by endogenous TNF-alpha. Although BCG and p40-expressing DC were both observed in splenic white pulp, p40(+) DC rarely colocalized with bacilli. Indeed, in vitro flow cytometry and confocal microscopy indicated that the presence of intracellular bacteria is not required for p40 production by DC and Transwell experiments confirmed that soluble mycobacterial components are sufficient for inducing cytokine expression by these cells. Moreover, when stimulated with LPS, DC directly infected with BCG showed impaired IL-12p40 production in vitro. Together, our findings establish CD11b(high) DC as a major source of IL-12/23p40 during mycobacterial infection in situ and implicate both soluble mycobacterial products and TNF-alpha in stimulating sustained production of p40 by these cells.
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http://dx.doi.org/10.4049/jimmunol.0900074DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2786988PMC
June 2009

The cell surface-exposed glycopeptidolipids confer a selective advantage to the smooth variants of Mycobacterium smegmatis in vitro.

FEMS Microbiol Lett 2009 Jan 12;290(1):39-44. Epub 2008 Nov 12.

Faculté de Médecine, Université Paris Descartes, Paris, France.

The cell surface of mycobacteria is quite rich in lipids. Glycopeptidolipids, surface-exposed lipids that typify some mycobacterial species, have been associated with a phenotypic switch between rough and smooth colony morphotypes. This conversion in Mycobacterium smegmatis is correlated with the absence/presence of glycopeptidolipids on the cell surface and is due to insertion sequence mobility. Here, we show that the occurrence of a high amount of glycopeptidolipids in the smooth variant leads to lower invasion abilities and lower internalization by macrophages. We further show that the high production of glycopeptidolipids on the cell surface can confer a selective advantage to the smooth variant when grown in vitro. This higher fitness under the laboratory condition might explain the selection of smooth variants in several independent laboratories. The implications of these findings are discussed.
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http://dx.doi.org/10.1111/j.1574-6968.2008.01396.xDOI Listing
January 2009

Protection against tuberculosis induced by oral prime with Mycobacterium bovis BCG and intranasal subunit boost based on the vaccine candidate Ag85B-ESAT-6 does not correlate with circulating IFN-gamma producing T-cells.

Vaccine 2009 Jan 31;27(1):28-37. Epub 2008 Oct 31.

Institut Pasteur, Unité de Génétique Mycobactérienne, 25-28 rue du Docteur Roux, 75724 Paris Cedex 15, France.

The potent IFN-gamma inducing fusion antigen Ag85B-ESAT-6 (85B6) is a lead subunit candidate to improve current vaccination against Mycobacterium tuberculosis (Mtb). The recombinant M. bovis BCG strain Myc3504 was constructed to secrete 85B6. It was based on commercial BCG strain Moreau Rio de Janeiro (BCG(MoWT)) which remains available for human oral administration. Myc 3504 induced higher levels of 85B6-specific IFN-gamma circulating T-cells as compared to BCG(MoWT). A novel needle-free mucosal immunization regimen combining oral prime with Myc3504 or BCG(MoWT) with intranasal boost with LTK-63-adjuvanted 85B6 was compared to subcutaneous prime-boost immunization. Strikingly whereas parenteral immunization induced sustained levels of 85B6-specific IFN-gamma secretion by circulating T-cells, mucosal regimens induced barely detectable IFN-gamma. Despite this, mice and guinea pigs immunized with the mucosal regimens were as efficiently protected against aerosol Mtb challenge as parenterally immunized animals. After Mtb challenge, anti-ESAT-6 IFN-gamma responses sharply increased in non-vaccinated mice as a hallmark of infection. Parenterally immunized mice that controlled Mtb infection, displayed anti-ESAT-6 IFN-gamma responses as high as non-immunized infected mice, compromising the possible use of ESAT-6 as a diagnostic tool. Interestingly, in mucosally immunized mice that were equally protected, post-challenge ESAT-6-specific IFN-gamma T-cell response remained low.
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http://dx.doi.org/10.1016/j.vaccine.2008.10.034DOI Listing
January 2009

Macrophage and T cell dynamics during the development and disintegration of mycobacterial granulomas.

Immunity 2008 Feb 7;28(2):271-84. Epub 2008 Feb 7.

Lymphocyte Biology Section, Laboratory of Immunology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD 20892, USA.

Granulomas play a key role in host protection against mycobacterial pathogens, with their breakdown contributing to exacerbated disease. To better understand the initiation and maintenance of these structures, we employed both high-resolution multiplex static imaging and intravital multiphoton microscopy of Mycobacterium bovis BCG-induced liver granulomas. We found that Kupffer cells directly capture blood-borne bacteria and subsequently nucleate formation of a nascent granuloma by recruiting both uninfected liver-resident macrophages and blood-derived monocytes. Within the mature granuloma, these myeloid cell populations formed a relatively immobile cellular matrix that interacted with a highly dynamic effector T cell population. The efficient recruitment of these T cells was highly dependent on TNF-alpha-derived signals, which also maintained the granuloma structure through preferential effects on uninfected macrophage populations. By characterizing the migration of both innate and adaptive immune cells throughout the process of granuloma development, these studies provide a new perspective on the cellular events involved in mycobacterial containment and escape.
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http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2390753PMC
http://dx.doi.org/10.1016/j.immuni.2007.12.010DOI Listing
February 2008

Mycobacterium bovis BCG-infected neutrophils and dendritic cells cooperate to induce specific T cell responses in humans and mice.

Eur J Immunol 2008 Feb;38(2):437-47

Unité Mixte de Recherche 7151 CNRS, Université Paris 7, Laboratoire d'immunologie cellulaire et immunopathologie de l'Ecole Pratique des Hautes Etudes, Institut Universitaire d'Hématologie, Hôpital Saint-Louis, Paris, France.

Neutrophils are increasingly thought to modulate dendritic cell (DC) functions. We investigated the role of the neutrophil-DC partnership in the response to Mycobacterium bovis BCG-the vaccine used against tuberculosis. We compared neutrophil-DC crosstalk in humans and mice, searching for functional differences. In both species, neutrophils captured fluorescent BCG-enhanced green fluorescent protein (EGFP) and were more phagocytic than DC. Non-apoptotic BCG-infected neutrophils clustered with immature DC, establishing intimate contacts with dendrites, at which fluorescent intact bacilli were observed. Physical interactions between neutrophils and DC were required for DC activation. Human BCG-infected DC produced interleukin (IL)-10, an inhibitory cytokine, whereas DC exposed to BCG-infected neutrophils produced low to undetectable amounts of the cytokine. Mouse BCG-infected neutrophils induced sustained IL-2 production by DC. Human DC exposed to BCG-infected neutrophils stimulated recall T cell reactivity from vaccinated donors. Mouse DC infected with recombinant ovalbumin (OVA)-producing BCG (rBCG(ova)) elicited proliferation of TCR-OVA-transgenic CD4 and CD8 T cells. Moreover, exposing DC to rBCG(ova)-infected neutrophils enhanced OVA presentation. Thus, in mice and humans, neutrophils help DC to cross-present BCG antigens to T cells. Our results suggest that this "ménage à trois" involving neutrophils, DC and T cells plays a major role in the immune response to BCG.
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http://dx.doi.org/10.1002/eji.200737905DOI Listing
February 2008

Selective suppression of dendritic cell functions by Mycobacterium ulcerans toxin mycolactone.

J Exp Med 2007 Jun 21;204(6):1395-403. Epub 2007 May 21.

Unité de Génétique Moléculaire Bactérienne, Genomes and Genetics Department, Institut Pasteur, 75724 Paris, Cedex 15, France.

Mycolactone is a polyketide toxin produced by Mycobacterium ulcerans (Mu), the causative agent of the skin disease Buruli ulcer (BU). Surprisingly, infected tissues lack inflammatory infiltrates. Structural similarities between mycolactone and immunosuppressive agents led us to investigate the immunomodulatory properties of mycolactone on dendritic cells (DCs), the key initiators and regulators of immune responses. At noncytotoxic concentrations, phenotypic and functional maturation of both mouse and human DCs was inhibited by mycolactone. Notably, mycolactone blocked the emigration of mouse-skin DCs to draining lymph nodes, as well as their maturation in vivo. In human peripheral blood-derived DCs, mycolactone inhibited the ability to activate allogeneic T cell priming and to produce inflammatory molecules. Interestingly, production of the cytokines interleukin (IL) 12, tumor necrosis factor alpha, and IL-6 was only marginally affected, whereas production of the chemokines macrophage inflammatory protein (MIP) 1alpha, MIP-1beta, regulated on activation, normal T cell expressed and secreted, interferon gamma-inducible protein 10, and monocyte chemoattractant protein 1 was abolished at nanomolar concentrations. Importantly, mycolactone endogenously expressed by Mu mediated similar inhibitory effects on beta-chemokine production by DCs. In accordance with the histopathological features of BUs, our results suggest that bacterial production of mycolactone may limit both the initiation of primary immune responses and the recruitment of inflammatory cells to the infection site. Moreover, they highlight a potential interest in mycolactone as a novel immunosuppressive agent.
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http://dx.doi.org/10.1084/jem.20070234DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2118602PMC
June 2007

Modification of the mycobacteriophage Ms6 attP core allows the integration of multiple vectors into different tRNAala T-loops in slow- and fast-growing mycobacteria.

BMC Mol Biol 2006 Dec 15;7:47. Epub 2006 Dec 15.

Unité de Génétique Mycobactérienne, Institut Pasteur, 25, rue du Dr Roux, 75724 Paris Cedex 15, France.

Background: Mycobacteriophage Ms6 integrates into Mycobacterium smegmatis and M. bovis BCG chromosome at the 3' end of tRNAala genes. Homologous recombination occurs between the phage attP core and the attB site located in the T-loop. Integration-proficient vectors derived from Ms6 are useful genetic tools, but their insertion sites in the BCG chromosome remain poorly defined. The primary objective of this study was to identify Ms6 target genes in M. smegmatis and BCG. We then aimed to modify the attP site in Ms6-derived vectors, to switch integration to other tRNAala loci. This provided the basis for the development of recombinant M. bovis BCG strains expressing several reporter genes inserted into different tRNAala genes.

Results: The three tRNAala genes are highly conserved in M. smegmatis and BCG. However, in the T-loop of tRNAalaU and tRNAalaV containing the attB site, a single base difference was observed between the two species. We observed that the tRNAalaU gene was the only site into which Ms6-derived integration-proficient vectors integrated in M. smegmatis, whereas in BCG, the tRNAalaV gene was used as the target. No integration occurred in the BCG tRNAalaU T-loop, despite a difference of only one base from the 26-base Ms6 attP core. We mutated the attP core to give a perfect match with the other tRNAala T-loops from M. smegmatis and BCG. Modification of the seven-base T-loop decreased integration efficiency, identifying this site as a possible site of strand exchange. Finally, two Ms6 vectors were constructed to integrate two reporter genes into the tRNAalaU and tRNAalaV T-loops of the same BCG chromosome.

Conclusion: Small changes in the 7 bp T-loop attP site of Ms6 made it possible to use another attB site, albeit with a lower integration efficiency. These molecular studies on BCG tRNAala genes made it possible to create valuable tools for the site-directed insertion of several genes in the same BCG strain. These tools will be useful for the development of novel multivalent vaccines and genetic studies.
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http://dx.doi.org/10.1186/1471-2199-7-47DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1762012PMC
December 2006

The virulence-associated two-component PhoP-PhoR system controls the biosynthesis of polyketide-derived lipids in Mycobacterium tuberculosis.

J Biol Chem 2006 Jan 2;281(3):1313-6. Epub 2005 Dec 2.

Departamento de Microbiología, Medicina Preventiva y Salud Pública, Universidad de Zaragoza, C/Domingo Miral sin numero, 50009 Zaragoza, Spain.

Two-component regulatory signal transduction systems are important elements of the adaptative response of prokaryotes to a variety of environmental stimuli. Disruption of PhoP-PhoR in Mycobacterium tuberculosis dramatically attenuates virulence, implying that this system directly and/or indirectly coordinates the expression of important virulence factors whose identity remains to be established. Interestingly, in knockingout the PhoP-PhoR two-component system in M. tuberculosis Mt103, dramatic changes in the colonial morphology, cording properties, and reactivity of the mutant strain to the basic dye neutral red, all intrinsic properties of tubercle bacilli known to correlate with virulence, were noted. Because deficiencies in the ability of the mutant to form serpentine cords and stain with the dye are likely the results of alterations of its cell envelope composition, we undertook to analyze the lipid content of phoP and phoP-phoR mutants constructed in two different strains of M. tuberculosis. Our results indicate that PhoP coordinately and positively regulates the synthesis of methyl-branched fatty acid-containing acyltrehaloses known to be restricted to pathogenic species of the M. tuberculosis complex, namely diacyltrehaloses, polyacyltrehaloses, and sulfolipids. Evidence is also provided that PhoP but not PhoR is required for the production of these lipids. This work represents an important step toward the functional characterization of PhoP-PhoR and the understanding of complex lipid synthesis in M. tuberculosis.
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http://dx.doi.org/10.1074/jbc.C500388200DOI Listing
January 2006

Neutrophils rapidly migrate via lymphatics after Mycobacterium bovis BCG intradermal vaccination and shuttle live bacilli to the draining lymph nodes.

Blood 2005 Sep 10;106(5):1843-50. Epub 2005 May 10.

Mycobacterial Genetics Unit, Institut Pasteur, 25 rue du Docteur Roux, 7724 Paris Cedex 15, France.

The early innate response after Mycobacterium bovis bacille Calmette-Guérin (BCG) vaccination is poorly characterized but probably decisive for subsequent protective immunity against tuberculosis. Therefore, we vaccinated mice with fluorescent BCG strains in the ear dorsum, as a surrogate of intradermal vaccination in humans. During the first 3 days, we tracked BCG host cells migrating out of the dermis to the auricular draining lymph nodes (ADLNs). Resident skin dendritic cells (DCs) or macrophages did not play a predominant role in early BCG capture and transport to ADLNs. The main BCG host cells rapidly recruited both in the dermis and ADLNs were neutrophils. Fluorescent green or red BCG strains injected into nonoverlapping sites were essentially sheltered by distinct neutrophils in the ADLN capsule, indicating that neutrophils had captured bacilli in peripheral tissue and transported them to the lymphoid organ. Strikingly, we observed BCG-infected neutrophils in the lumen of lymphatic vessels by confocal microscopy on ear dermis. Fluorescence-labeled neutrophils injected into the ears accumulated exclusively into the ipsilateral ADLN capsule after BCG vaccination. Thus, we provide in vivo evidence that neutrophils, like DCs or inflammatory monocytes, migrate via afferent lymphatics to lymphoid tissue and can shuttle live microorganisms.
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http://dx.doi.org/10.1182/blood-2005-03-1281DOI Listing
September 2005

Disruption of the langerin/CD207 gene abolishes Birbeck granules without a marked loss of Langerhans cell function.

Mol Cell Biol 2005 Jan;25(1):88-99

Centre d'Immunologie de Marseille-Luminy, INSERM-CNRS-Université de la Méditerranee, Parc Scientifique de Luminy, Marseille, France.

Langerin is a C-type lectin expressed by a subset of dendritic leukocytes, the Langerhans cells (LC). Langerin is a cell surface receptor that induces the formation of an LC-specific organelle, the Birbeck granule (BG). We generated a langerin(-/-) mouse on a C57BL/6 background which did not display any macroscopic aberrant development. In the absence of langerin, LC were detected in normal numbers in the epidermis but the cells lacked BG. LC of langerin(-/-) mice did not present other phenotypic alterations compared to wild-type littermates. Functionally, the langerin(-/-) LC were able to capture antigen, to migrate towards skin draining lymph nodes, and to undergo phenotypic maturation. In addition, langerin(-/-) mice were not impaired in their capacity to process native OVA protein for I-A(b)-restricted presentation to CD4(+) T lymphocytes or for H-2K(b)-restricted cross-presentation to CD8(+) T lymphocytes. langerin(-/-) mice inoculated with mannosylated or skin-tropic microorganisms did not display an altered pathogen susceptibility. Finally, chemical mutagenesis resulted in a similar rate of skin tumor development in langerin(-/-) and wild-type mice. Overall, our data indicate that langerin and BG are dispensable for a number of LC functions. The langerin(-/-) C57BL/6 mouse should be a valuable model for further functional exploration of langerin and the role of BG.
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http://dx.doi.org/10.1128/MCB.25.1.88-99.2005DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC538791PMC
January 2005