Publications by authors named "Clémence Rougeaux"

11 Publications

  • Page 1 of 1

Ricin Antibodies' Neutralizing Capacity against Different Ricin Isoforms and Cultivars.

Toxins (Basel) 2021 01 29;13(2). Epub 2021 Jan 29.

Paris-Saclay University, CEA, INRAE, Medicines and Healthcare Technologies Department (DMTS), SPI, 91191 Gif-sur-Yvette, France.

Ricin, a highly toxic protein from , is considered a potential biowarfare agent. Despite the many data available, no specific treatment has yet been approved. Due to their ability to provide immediate protection, antibodies (Abs) are an approach of choice. However, their high specificity might compromise their capacity to protect against the different ricin isoforms (D and E) found in the different cultivars. In previous work, we have shown the neutralizing potential of different Abs (43RCA-G1 (anti ricin A-chain) and RB34 and RB37 (anti ricin B-chain)) against ricin D. In this study, we evaluated their protective capacity against both ricin isoforms. We show that: (i) RB34 and RB37 recognize exclusively ricin D, whereas 43RCA-G1 recognizes both isoforms, (ii) their neutralizing capacity in vitro varies depending on the cultivar, and (iii) there is a synergistic effect when combining RB34 and 43RCA-G1. This effect is also demonstrated in vivo in a mouse model of intranasal intoxication with ricin D/E (1:1), where approximately 60% and 40% of mice treated 0 and 6 h after intoxication, respectively, are protected. Our results highlight the importance of evaluating the effectiveness of the Abs against different ricin isoforms to identify the treatment with the broadest spectrum neutralizing effect.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.3390/toxins13020100DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7911099PMC
January 2021

Differential serological and neutralizing antibody dynamics after an infection by a single SARS-CoV-2 strain.

Infection 2021 Jan 2. Epub 2021 Jan 2.

Microbiology and Infectious Diseases Department, Institut de Recherche Biomédicale des Armées (IRBA), 1 place Général Valérie André, 91220, Brétigny sur Orge, France.

Background: We report here the case of two coworkers infected by the same SARS-CoV-2 strain, presenting two different immunological outcomes.

Case: One patient presented a strong IgG anti-receptor-binding domain immune response correlated with a low and rapidly decreasing titer of neutralizing antibodies. The other patient had a similar strong IgG anti-receptor-binding domain immune response but high neutralizing antibody titers.

Discussion And Conclusion: Thus, host individual factors may be the main drivers of the immune response varying with age and clinical severity.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1007/s15010-020-01556-8DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7776280PMC
January 2021

Anthrax Toxin Detection: From in Vivo Studies to Diagnostic Applications.

Microorganisms 2020 Jul 23;8(8). Epub 2020 Jul 23.

Unité Bactériologie Biothérapies Anti-infectieuses et Immunité, Institut de Recherche Biomédicale des Armées (IRBA), 1 place Général Valérie André, 91220 Brétigny sur Orge, France.

Anthrax toxins are produced by throughout infection and shape the physiopathogenesis of the disease. They are produced in low quantities but are highly efficient. They have thus been long ignored, but recent biochemical methods have improved our knowledge in animal models. This article reviews the various methods that have been used and how they could be applied to clinical diagnosis.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.3390/microorganisms8081103DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7464488PMC
July 2020

Very Early Blood Diffusion of the Active Lethal and Edema Factors of Bacillus anthracis After Intranasal Infection.

J Infect Dis 2020 02;221(4):660-667

Unité Biothérapies Anti-Infectieuses et Immunité, Institut de Recherche Biomédicale des Armées, Brétigny-sur-Orge, France.

Background: Lethal and edema toxins are critical virulence factors of Bacillus anthracis. Few data are available on their presence in the early stage of intranasal infection.

Methods: To investigate the diffusion of edema factor (EF) and lethal factor (LF), we use sensitive quantitative methods to measure their enzymatic activities in mice intranasally challenged with a wild-type B anthracis strain or with an isogenic mutant deficient for the protective antigen.

Results: One hour after mouse challenge, although only 7% of mice presented bacteremia, LF and EF were detected in the blood of 100% and 42% of mice, respectively. Protective antigen facilitated the diffusion of LF and EF into the blood compartment. Toxins played a significant role in the systemic dissemination of B anthracis in the blood, spleen, and liver. A mouse model of intoxination further confirmed that LT and ET could diffuse rapidly in the circulation, independently of bacteria.

Conclusions: In this inhalational model, toxins have disseminated rapidly in the blood, playing a significant and novel role in the early systemic diffusion of bacteria, demonstrating that they may represent a very early target for the diagnosis and the treatment of anthrax.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1093/infdis/jiz497DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6996859PMC
February 2020

Questionable Efficacy of Therapeutic Antibodies in the Treatment of Anthrax.

mSphere 2019 06 19;4(3). Epub 2019 Jun 19.

Institut de Recherche Biomédicale des Armées, Bacteriology, Anti-infectious Biotherapies, and Immunity Unit, Brétigny-sur-Orge, France.

Inhalational anthrax caused by , a spore-forming Gram-positive bacterium, is a highly lethal infection. Antibodies targeting the protective antigen (PA) binding component of the toxins have recently been authorized as an adjunct to antibiotics, although no conclusive evidence demonstrates that anthrax antitoxin therapy has any significant benefit. We discuss here the rational basis of anti-PA development regarding the pathogenesis of the disease. We argue that inductive reasoning may induce therapeutic bias. We identified anthrax animal model analysis as another bias. Further studies are needed to assess the benefit of anti-PA antibodies in the treatment of inhalational anthrax, while a clearer consensus should be established around what evidence should be proven in an anthrax model.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1128/mSphere.00282-19DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6584371PMC
June 2019

In vivo dynamics of active edema and lethal factors during anthrax.

Sci Rep 2016 Mar 21;6:23346. Epub 2016 Mar 21.

Pathogénie des Toxi-Infections Bactériennes, Institut Pasteur, Paris, France.

Lethal and edema toxins are critical virulence factors of Bacillus anthracis. However, little is known about their in vivo dynamics of production during anthrax. In this study, we unraveled for the first time the in vivo kinetics of production of the toxin components EF (edema factor) and LF (lethal factor) during cutaneous infection with a wild-type toxinogenic encapsulated strain in immuno-competent mice. We stratified the asynchronous infection process into defined stages through bioluminescence imaging (BLI), while exploiting sensitive quantitative methods by measuring the enzymatic activity of LF and EF. LF was produced in high amounts, while EF amounts steadily increased during the infectious process. This led to high LF/EF ratios throughout the infection, with variations between 50 to a few thousands. In the bloodstream, the early detection of active LF and EF despite the absence of bacteria suggests that they may exert long distance effects. Infection with a strain deficient in the protective antigen toxin component enabled to address its role in the diffusion of LF and EF within the host. Our data provide a picture of the in vivo complexity of the infectious process.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1038/srep23346DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4800402PMC
March 2016

Micropatterned macrophage analysis reveals global cytoskeleton constraints induced by Bacillus anthracis edema toxin.

Infect Immun 2015 Aug 26;83(8):3114-25. Epub 2015 May 26.

Unité Interactions Hôte-Agents pathogènes, Institut de Recherche Biomédicale des Armées, Brétigny-sur-Orge, France Laboratoire Pathogénie des Toxi-Infections Bactériennes, Institut Pasteur, Paris, France Ecole du Val-de-Grâce, Paris, France

Bacillus anthracis secretes the edema toxin (ET) that disrupts the cellular physiology of endothelial and immune cells, ultimately affecting the adherens junction integrity of blood vessels that in turn leads to edema. The effects of ET on the cytoskeleton, which is critical in cell physiology, have not been described thus far on macrophages. In this study, we have developed different adhesive micropatterned surfaces (L and crossbow) to control the shape of bone marrow-derived macrophages (BMDMs) and primary peritoneal macrophages. We found that macrophage F-actin cytoskeleton adopts a specific polar organization slightly different from classical human HeLa cells on the micropatterns. Moreover, ET induced a major quantitative reorganization of F-actin within 16 h with a collapse at the nonadhesive side of BMDMs along the nucleus. There was an increase in size and deformation into a kidney-like shape, followed by a decrease in size that correlates with a global cellular collapse. The collapse of F-actin was correlated with a release of focal adhesion on the patterns and decreased cell size. Finally, the cell nucleus was affected by actin reorganization. By using this technology, we could describe many previously unknown macrophage cellular dysfunctions induced by ET. This novel tool could be used to analyze more broadly the effects of toxins and other virulence factors that target the cytoskeleton.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1128/IAI.00479-15DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4496603PMC
August 2015

Noninvasive imaging technologies reveal edema toxin as a key virulence factor in anthrax.

Am J Pathol 2011 Jun;178(6):2523-35

Pathogenesis of Bacterial Toxi-Infections Laboratory, Pasteur Institute (Institut Pasteur), Paris, France.

Powerful noninvasive imaging technologies enable real-time tracking of pathogen-host interactions in vivo, giving access to previously elusive events. We visualized the interactions between wild-type Bacillus anthracis and its host during a spore infection through bioluminescence imaging coupled with histology. We show that edema toxin plays a central role in virulence in guinea pigs and during inhalational infection in mice. Edema toxin (ET), but not lethal toxin (LT), markedly modified the patterns of bacterial dissemination leading, to apparent direct dissemination to the spleen and provoking apoptosis of lymphoid cells. Each toxin alone provoked particular histological lesions in the spleen. When ET and LT are produced together during infection, a specific temporal pattern of lesion developed, with early lesions typical of LT, followed at a later stage by lesions typical of ET. Our study provides new insights into the complex spatial and temporal effects of B. anthracis toxins in the infected host, suggesting a greater role than previously suspected for ET in anthrax and suggesting that therapeutic targeting of ET contributes to protection.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.ajpath.2011.02.027DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3124019PMC
June 2011

Apical expression of human full-length hCEACAM1-4L protein renders the Madin Darby Canine Kidney cells responsive to lipopolysaccharide leading to TLR4-dependent Erk1/2 and p38 MAPK signalling.

Cell Microbiol 2011 May 24;13(5):764-85. Epub 2011 Feb 24.

INSERM, UMR756 «Signalisation et Physiopathologie des Cellules Epithéliales», Châtenay-Malabry, France Université Paris-Sud 11, Faculté de Pharmacie, Châtenay-Malabry, France.

CEACAM1 expressed by granulocytes and epithelial cells is recognized as a membrane-associated receptor by some Gram-negative pathogens. Here we report a previously unsuspected role of human CEACAM1-4L (hCEACAM1-4L) in polarized epithelial cells. We find that in contrast with non-transfected cells, Madin Darby Canine Kidney strain II (MDCK) engineered for the apical expression of the long cytoplasmic chain protein hCEACAM1-4L showed a serum-independent increase in the phosphorylation of the extracellular signal-regulated kinase 1/2 (Erk1/2) and p38 mitogen-activated protein kinases (MAPKs) after treatment with lipopolysaccharide (LPS) of wild-type, diffusely adhering Afa/Dr Escherichia coli (Afa/Dr DAEC) strain IH11128. Aggregates of FITC-LPS bind the apical domain of MDCK-hCEACAM1-4L cells colocalizing with the apically expressed hCEACAM1-4L protein and do not bind MDCK-pCEP cells, and surface plasmon resonance analysis shows that LPS binds to the extracellular domain of the CEACAM1-4L protein. We showed that cell polarization and lipid rafts positively control the LPS-IH11128-induced phosphorylation of Erk1/2 in MDCK-hCEACAM1-4L cells. Structure-function analysis using mutated hCEACAM1-4L protein shows that the cytoplasmic domain of the protein is needed for LPS-induced MAPK signalling, and that phosphorylation of Tyr-residues is not increased in association with MAPK signalling. The hCEACAM1-4L-dependent Erk1/2 phosphorylation develops in the presence of lipid A and does not develop in the presence of penta-acylated LPS. Finally, small interfering RNA (siRNA) silencing of canine TLR4 abolishes the hCEACAM1-4L-dependent, LPS-induced phosphorylation of Erk1/2. Collectively, our results support the notion that the apically expressed, full-length hCEACAM1-4L protein functions as a novel LPS-conveying molecule at the mucosal surface of polarized epithelial cells for subsequent MD-2/TLR4 receptor-dependent MAPK Erk1/2 and p38 signalling.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1111/j.1462-5822.2011.01575.xDOI Listing
May 2011

hCEACAM1-4L downregulates hDAF-associated signalling after being recognized by the Dr adhesin of diffusely adhering Escherichia coli.

Cell Microbiol 2008 Mar 2;10(3):632-54. Epub 2007 Nov 2.

INSERM, UMR756 Signalisation et Physiopathologie des Cellules Epithéliales, Châtenay-Malabry, France, and Université Paris-Sud XI, Faculté de Pharmacie, Châtenay-Malabry, France.

Human decay accelerating factor (hDAF, CD55) and members of the carcinoembryonic-antigen-related cell-adhesion molecules (hCEACAMs) family are recognized as receptors by Gram-negative, diffusely adhering Escherichia coli (DAEC) strains expressing Afa/Dr adhesins. We report here that hCEACAM1-4L has a key function in downregulating the protein tyrosine Src kinase associated with hDAF signalling. After infecting HeLa epithelial cells stably transfected with hCEACAM1-4L cDNA with Dr adhesin-positive E. coli, the amount of the pTyr(416)-active form of the Src protein decreased, whereas that of the pTyr(527)-inactive form of Src protein did not increase. This downregulation of the Src protein implies that part of the hCEACAM1-4L protein had been translocated into lipid rafts, the protein was phosphorylated at Tyr residues in the cytoplasmic domain, and it was physically associated with the protein tyrosine phosphatase, SHP-2. Finally, we found that the hCEACAM1-4L-associated SHP-2 was not phosphorylated and lacked phosphatase activity, suggesting that the downregulation of Src protein associated with hDAF signalling results from the absence of dephosphorylation of the pTyr(527)-inactive form necessary for Src kinase activation.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1111/j.1462-5822.2007.01072.xDOI Listing
March 2008