Publications by authors named "Julie Dano"

9 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.
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http://dx.doi.org/10.3390/toxins13020100DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7911099PMC
January 2021

Role of T3SS-1 SipD Protein in Protecting Mice against Non-typhoidal Salmonella Typhimurium.

PLoS Negl Trop Dis 2016 12 19;10(12):e0005207. Epub 2016 Dec 19.

Service de Pharmacologie et Immunoanalyse (SPI), CEA, INRA, Université Paris-Saclay, Gif-sur-Yvette, France.

Background: Salmonella enterica species are enteric pathogens that cause severe diseases ranging from self-limiting gastroenteritis to enteric fever and sepsis in humans. These infectious diseases are still the major cause of morbidity and mortality in low-income countries, especially in children younger than 5 years and immunocompromised adults. Vaccines targeting typhoidal diseases are already marketed, but none protect against non-typhoidal Salmonella. The existence of multiple non-typhoidal Salmonella serotypes as well as emerging antibiotic resistance highlight the need for development of a broad-spectrum protective vaccine. All Salmonella spp. utilize two type III Secretion Systems (T3SS 1 and 2) to initiate infection, allow replication in phagocytic cells and induce systemic disease. T3SS-1, which is essential to invade epithelial cells and cross the barrier, forms an extracellular needle and syringe necessary to inject effector proteins into the host cell. PrgI and SipD form, respectively, the T3SS-1 needle and the tip complex at the top of the needle. Because they are common and highly conserved in all virulent Salmonella spp., they might be ideal candidate antigens for a subunit-based, broad-spectrum vaccine.

Principal Findings: We investigated the immunogenicity and protective efficacy of PrgI and SipD administered by subcutaneous, intranasal and oral routes, alone or combined, in a mouse model of Salmonella intestinal challenge. Robust IgG (in all immunization routes) and IgA (in intranasal and oral immunization routes) antibody responses were induced against both proteins, particularly SipD. Mice orally immunized with SipD alone or SipD combined with PrgI were protected against lethal intestinal challenge with Salmonella Typhimurium (100 Lethal Dose 50%) depending on antigen, route and adjuvant.

Conclusions And Significance: Salmonella T3SS SipD is a promising antigen for the development of a protective Salmonella vaccine, and could be developed for vaccination in tropical endemic areas to control infant mortality.
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http://dx.doi.org/10.1371/journal.pntd.0005207DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5167260PMC
December 2016

Recommended Immunological Strategies to Screen for Botulinum Neurotoxin-Containing Samples.

Toxins (Basel) 2015 Nov 26;7(12):5011-34. Epub 2015 Nov 26.

Biological Toxins, Centre for Biological Threats and Special Pathogens, Robert Koch Institute, Seestrasse 10, 13353 Berlin, Germany.

Botulinum neurotoxins (BoNTs) cause the life-threatening neurological illness botulism in humans and animals and are divided into seven serotypes (BoNT/A-G), of which serotypes A, B, E, and F cause the disease in humans. BoNTs are classified as "category A" bioterrorism threat agents and are relevant in the context of the Biological Weapons Convention. An international proficiency test (PT) was conducted to evaluate detection, quantification and discrimination capabilities of 23 expert laboratories from the health, food and security areas. Here we describe three immunological strategies that proved to be successful for the detection and quantification of BoNT/A, B, and E considering the restricted sample volume (1 mL) distributed. To analyze the samples qualitatively and quantitatively, the first strategy was based on sensitive immunoenzymatic and immunochromatographic assays for fast qualitative and quantitative analyses. In the second approach, a bead-based suspension array was used for screening followed by conventional ELISA for quantification. In the third approach, an ELISA plate format assay was used for serotype specific immunodetection of BoNT-cleaved substrates, detecting the activity of the light chain, rather than the toxin protein. The results provide guidance for further steps in quality assurance and highlight problems to address in the future.
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http://dx.doi.org/10.3390/toxins7124860DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4690110PMC
November 2015

Recommended Immunological Assays to Screen for Ricin-Containing Samples.

Toxins (Basel) 2015 Nov 26;7(12):4967-86. Epub 2015 Nov 26.

Bacteriology & Enteric Diseases Division, National Microbiology Laboratory, Public Health Agency of Canada,Winnipeg, MB R3E 3R2, Canada.

Ricin, a toxin from the plant Ricinus communis, is one of the most toxic biological agents known. Due to its availability, toxicity, ease of production and absence of curative treatments, ricin has been classified by the Centers for Disease Control and Prevention (CDC) as category B biological weapon and it is scheduled as a List 1 compound in the Chemical Weapons Convention. An international proficiency test (PT) was conducted to evaluate detection and quantification capabilities of 17 expert laboratories. In this exercise one goal was to analyse the laboratories' capacity to detect and differentiate ricin and the less toxic, but highly homologuous protein R. communis agglutinin (RCA120). Six analytical strategies are presented in this paper based on immunological assays (four immunoenzymatic assays and two immunochromatographic tests). Using these immunological methods "dangerous" samples containing ricin and/or RCA120 were successfully identified. Based on different antibodies used the detection and quantification of ricin and RCA120 was successful. The ricin PT highlighted the performance of different immunological approaches that are exemplarily recommended for highly sensitive and precise quantification of ricin.
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http://dx.doi.org/10.3390/toxins7124858DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4690108PMC
November 2015

Multiplex quantification of protein toxins in human biofluids and food matrices using immunoextraction and high-resolution targeted mass spectrometry.

Anal Chem 2015 Aug 29;87(16):8473-80. Epub 2015 Jul 29.

†CEA, DSV, iBiTec-S, Laboratoire d'études du métabolisme des médicaments, 91191 Gif-sur-Yvette, France.

The development of rapid methods for unambiguous identification and precise quantification of protein toxins in various matrices is essential for public health surveillance. Nowadays, analytical strategies classically rely on sensitive immunological assays, but mass spectrometry constitutes an attractive complementary approach thanks to direct measurement and protein characterization ability. We developed here an innovative multiplex immuno-LC-MS/MS method for the simultaneous and specific quantification of the three potential biological warfare agents, ricin, staphylococcal enterotoxin B, and epsilon toxin, in complex human biofluids and food matrices. At least 7 peptides were targeted for each toxin (43 peptides in total) with a quadrupole-Orbitrap high-resolution instrument for exquisite detection specificity. Quantification was performed using stable isotope-labeled toxin standards spiked early in the sample. Lower limits of quantification were determined at or close to 1 ng·mL(-1). The whole process was successfully applied to the quantitative analysis of toxins in complex samples such as milk, human urine, and plasma. Finally, we report new data on toxin stability with no evidence of toxin degradation in milk in a 48 h time frame, allowing relevant quantitative toxin analysis for samples collected in this time range.
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http://dx.doi.org/10.1021/acs.analchem.5b01900DOI Listing
August 2015

Fast and direct extraction of cell-associated hepatotoxins from toxic cyanobacteria.

Water Environ Res 2014 May;86(5):470-7

Microcystins are an important group of toxins produced by cyanobacteria of different genera. An increasing number of water contaminations by this class of toxins have been reported that are susceptible to generate important public health problems. We designed an efficient method for extracting these toxins on-site for a rapid testing of potentially contaminated water. The extraction parameters have been optimized using Microcystis aeruginosa and the technique successfully applied to different laboratory cultures and field samples. The procedure employs a simple and stable reagent mix of propanol, Tween 20, and trifluoroacetic acid. It is directly active on crude cell suspensions without any pre-treatment. Extraction yields measured by immunological quantification were at least equal to the best values obtained with the most commonly used laboratory techniques. An additional simple concentration/extraction step is also described that allows measurements on samples too dilute for direct detection by immunochromatographic techniques.
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http://dx.doi.org/10.2175/106143013x13807328849891DOI Listing
May 2014

A one-step and biocompatible cellulose functionalization for covalent antibody immobilization on immunoassay membranes.

J Mater Chem B 2013 Jul 24;1(26):3277-3286. Epub 2013 May 24.

CEA/DSM/IRAMIS/SPCSI/Laboratoire de Chimie des Surfaces et Interfaces (LCSI), Gif sur Yvette, F-91191, France.

Among bioactive papers, many multiplexed assays implement methods incompatible with the conventional lateral flow immunoassay (LFIA) carrier material, nitrocellulose. Consequently, its replacement by cellulose has to be considered. This technological breakthrough requires a surface chemistry which ensures both the biomolecules covalent grafting to cellulose and the conservation of their biological activity. To comply with these requirements, the process elaborated in this study implements compounds and methods compatible with biological material. While cellulose chemical modification is usually operated under harsh conditions in organic solvents, the diazonium-based functionalization procedure presented here was performed onto cellulose sheets in water and at room temperature. Paper sheets have been successfully modified and bear different chemical functions which enable grafting of biomolecules by common bioconjugate techniques and to perform LFIAs. More generally, the chemical ways developed in this study are suitable for many biomolecules and would be helpful for any sensitive molecule immobilization onto cellulose sheets.
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http://dx.doi.org/10.1039/c3tb20380hDOI Listing
July 2013

Fast and sensitive detection of Bacillus anthracis spores by immunoassay.

Appl Environ Microbiol 2012 Sep 6;78(18):6491-8. Epub 2012 Jul 6.

CEA Service de Pharmacologie et d'Immunoanalyse, CEA/Saclay, Gif sur Yvette, France.

Bacillus anthracis is one of the most dangerous potential biological weapons, and it is essential to develop a rapid and simple method to detect B. anthracis spores in environmental samples. The immunoassay is a rapid and easy-to-use method for the detection of B. anthracis by means of antibodies directed against surface spore antigens. With this objective in view, we have produced a panel of monoclonal antibodies against B. anthracis and developed colorimetric and electrochemiluminescence (ECL) immunoassays. Using Meso Scale Discovery ECL technology, which is based on electrochemiluminescence (ECL) detection utilizing a sulfo-Tag label that emits light upon electrochemical stimulation (using a dedicated ECL plate reader, an electrical current is placed across the microplate with electrodes integrated into the bottom of the plate, resulting in a series of electrically induced reactions leading to a luminescent signal), a detection limit ranging between 0.3 × 10(3) and 10(3) CFU/ml (i.e., 30 to 100 spores per test), depending on the B. anthracis strain assayed, was achieved. In complex matrices (5 mg/ml of soil or simulated powder), the detection level (without any sample purification or concentration) was never altered more than 3-fold compared with the results obtained in phosphate-buffered saline.
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http://dx.doi.org/10.1128/AEM.01282-12DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3426714PMC
September 2012

Characterization of botulinum neurotoxin type A neutralizing monoclonal antibodies and influence of their half-lives on therapeutic activity.

PLoS One 2010 Aug 26;5(8):e12416. Epub 2010 Aug 26.

Unité des Bactéries anaérobies et Toxines, Institut Pasteur, Paris, France.

Botulinum toxins, i.e. BoNT/A to/G, include the most toxic substances known. Since botulism is a potentially fatal neuroparalytic disease with possible use as a biowarfare weapon (Centers for Disease Control and Prevention category A bioterrorism agent), intensive efforts are being made to develop vaccines or neutralizing antibodies. The use of active fragments from non-human immunoglobulins (F(ab')(2), Fab', scFv), chemically modified or not, may avoid side effects, but also largely modify the in vivo half-life and effectiveness of these reagents. We evaluated the neutralizing activity of several monoclonal anti-BoNT/A antibodies (mAbs). F(ab')(2) fragments, native or treated with polyethyleneglycol (PEG), were prepared from selected mAbs to determine their half-life and neutralizing activity as compared with the initial mAbs. We compared the protective efficiency of the different biochemical forms of anti-toxin mAbs providing the same neutralizing activity. Among fourteen tested mAbs, twelve exhibited neutralizing activity. Fragments from two of the best mAbs (TA12 and TA17), recognizing different epitopes, were produced. These two mAbs neutralized the A1 subtype of the toxin more efficiently than the A2 or A3 subtypes. Since mAb TA12 and its fragments both exhibited the greatest neutralizing activity, they were further evaluated in the therapeutic experiments. These showed that, in a mouse model, a 2- to 4-h interval between toxin and antitoxin injection allows the treatment to remain effective, but also suggested an absence of correlation between the half-life of the antitoxins and the length of time before treatment after botulinum toxin A contamination. These experiments demonstrate that PEG treatment has a strong impact on the half-life of the fragments, without affecting the effectiveness of neutralization, which was maintained after preparation of the fragments. These reagents may be useful for rapid treatment after botulinum toxin A contamination.
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http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0012416PLOS
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2928723PMC
August 2010