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Tolman LE, Mantis NJ. Inflammatory Profiles Induced by Intranasal Immunization with Ricin Toxin-immune Complexes. Immunohorizons 2024; 8:457-463. [PMID: 38922287 PMCID: PMC11220739 DOI: 10.4049/immunohorizons.2400007] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2024] [Accepted: 05/29/2024] [Indexed: 06/27/2024] Open
Abstract
The underlying contribution of immune complexes in modulating adaptive immunity in mucosal tissues remains poorly understood. In this report, we examined, in mice, the proinflammatory response elicited by intranasal delivery of the biothreat agent ricin toxin (RT) in association with two toxin-neutralizing mAbs, SylH3 and PB10. We previously demonstrated that ricin-immune complexes (RICs) induce the rapid onset of high-titer toxin-neutralizing Abs that persist for months. We now demonstrate that such responses are dependent on CD4+ T cell help, because treatment of mice with an anti-CD4 mAb abrogated the onset of RT-specific Abs following intranasal RICs exposure. To define the inflammatory environment associated with RIC exposure, we collected bronchoalveolar lavage fluid (BALF) and sera from mice 6, 12, and 18 h after they had received RT or RICs by the intranasal route. A 32-plex cytometric bead array revealed an inflammatory profile elicited by RT that was dominated by IL-6 (>1500-fold increase in BALF) and secondarily by KC (CXCL1), G-CSF, GM-CSF, and MCP-1. RICs induced inflammatory profiles in both BALF and serum response that were similar to RT, albeit at markedly reduced levels. These results demonstrate that RICs retain the capacity to induce local and systemic inflammatory cytokines/chemokines that, in turn, may influence Ag sampling and presentation in the lung mucosa and draining lymph nodes. A better understanding of the fate of immune complexes following intranasal delivery has implications for the development of mucosal vaccines for biothreats and emerging infectious diseases.
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Affiliation(s)
- Lindsey E. Tolman
- Department of Biomedical Sciences, School of Public Health, University at Albany, Albany, NY
| | - Nicholas J. Mantis
- Department of Biomedical Sciences, School of Public Health, University at Albany, Albany, NY
- Division of Infectious Diseases, Wadsworth Center, New York State Department of Health, Albany, NY
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2
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Zhou YT, Li S, Du SL, Zhao JH, Cai YQ, Zhang ZQ. The multifaceted role of macrophage mitophagy in SiO 2-induced pulmonary fibrosis: A brief review. J Appl Toxicol 2024. [PMID: 38644760 DOI: 10.1002/jat.4612] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2024] [Revised: 03/19/2024] [Accepted: 03/28/2024] [Indexed: 04/23/2024]
Abstract
Prolonged exposure to environments with high concentrations of crystalline silica (CS) can lead to silicosis. Macrophages play a crucial role in the pathogenesis of silicosis. In the process of silicosis, silica (SiO2) invades alveolar macrophages (AMs) and induces mitophagy which usually exists in three states: normal, excessive, and/or deficiency. Different mitophagy states lead to corresponding toxic responses, including successful macrophage repair, injury, necrosis, apoptosis, and even pulmonary fibrosis. This is a complex process accompanied by various cytokines. Unfortunately, the details have not been fully systematically summarized. Therefore, it is necessary to elucidate the role of macrophage mitophagy in SiO2-induced pulmonary fibrosis by systematic analysis on the literature reports. In this review, we first summarized the current data on the macrophage mitophagy in the development of SiO2-induced pulmonary fibrosis. Then, we introduce the molecular mechanism on how SiO2-induced mitophagy causes pulmonary fibrosis. Finally, we focus on introducing new therapies based on newly developed mitophagy-inducing strategies. We conclude that macrophage mitophagy plays a multifaceted role in the progression of SiO2-induced pulmonary fibrosis, and reprogramming the macrophage mitophagy state accordingly may be a potential means of preventing and treating pulmonary fibrosis.
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Affiliation(s)
- Yu-Ting Zhou
- Department of Public Health, Shandong First Medical University, Jinan, China
- Department of Public Health, Jining Medical University, Jining, China
| | - Shuang Li
- Department of Public Health, Jining Medical University, Jining, China
| | - Shu-Ling Du
- Department of Public Health, Jining Medical University, Jining, China
| | - Jia-Hui Zhao
- Department of Public Health, Jining Medical University, Jining, China
| | | | - Zhao-Qiang Zhang
- Department of Public Health, Jining Medical University, Jining, China
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3
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Vance DJ, Rudolph MJ, Davis SA, Mantis NJ. Structural Basis of Antibody-Mediated Inhibition of Ricin Toxin Attachment to Host Cells. Biochemistry 2023; 62:3181-3187. [PMID: 37903428 DOI: 10.1021/acs.biochem.3c00480] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/01/2023]
Abstract
Monoclonal antibodies, JB4 and SylH3, neutralize ricin toxin (RT) by inhibiting the galactose-specific lectin activity of the B subunit of the toxin (RTB), which is required for cell attachment and entry. It is not immediately apparent how the antibodies accomplish this feat, considering that RTB consists of two globular domains (D1, D2) each divided into three homologous subdomains (α, β, γ) with the two functional galactosyl-specific carbohydrate recognition domains (CRDs) situated on opposite poles (subdomains 1α and 2γ). Here, we report the X-ray crystal structures of JB4 and SylH3 Fab fragments bound to RTB in the context of RT. The structures revealed that neither Fab obstructed nor induced detectable conformational alterations in subdomains 1α or 2γ. Rather, JB4 and SylH3 Fabs recognize nearly identical epitopes within an ancillary carbohydrate recognition pocket located in subdomain 1β. Despite limited amino acid sequence similarity between SylH3 and JB4 Fabs, each paratope inserts a Phe side chain from the heavy (H) chain complementarity determining region (CDR3) into the 1β CRD pocket, resulting in local aromatic stacking interactions that potentially mimic a ligand interaction. Reconciling the fact that stoichiometric amounts of SylH3 and JB4 are sufficient to disarm RTB's lectin activity without evidence of allostery, we propose that subdomain 1β functions as a "coreceptor" required to stabilize glycan interactions principally mediated by subdomains 1α and 2γ. Further investigation into subdomain 1β will yield fundamental insights into the large family of R-type lectins and open novel avenues for countermeasures aimed at preventing toxin uptake into vulnerable tissues and cells.
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Affiliation(s)
- David J Vance
- Division of Infectious Diseases, Wadsworth Center, New York State Department of Health, Albany, New York 12208, United States
| | - Michael J Rudolph
- New York Structural Biology Center, New York, New York 10027, United States
| | - Simon A Davis
- New York Structural Biology Center, New York, New York 10027, United States
| | - Nicholas J Mantis
- Division of Infectious Diseases, Wadsworth Center, New York State Department of Health, Albany, New York 12208, United States
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Rasetti-Escargueil C, Avril A. Medical Countermeasures against Ricin Intoxication. Toxins (Basel) 2023; 15:toxins15020100. [PMID: 36828415 PMCID: PMC9966136 DOI: 10.3390/toxins15020100] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2022] [Revised: 12/14/2022] [Accepted: 01/16/2023] [Indexed: 01/22/2023] Open
Abstract
Ricin toxin is a disulfide-linked glycoprotein (AB toxin) comprising one enzymatic A chain (RTA) and one cell-binding B chain (RTB) contained in the castor bean, a Ricinus species. Ricin inhibits peptide chain elongation via disruption of the binding between elongation factors and ribosomes, resulting in apoptosis, inflammation, oxidative stress, and DNA damage, in addition to the classically known rRNA damage. Ricin has been used in traditional medicine throughout the world since prehistoric times. Because ricin toxin is highly toxic and can be readily extracted from beans, it could be used as a bioweapon (CDC B-list). Due to its extreme lethality and potential use as a biological weapon, ricin toxin remains a global public health concern requiring specific countermeasures. Currently, no specific treatment for ricin intoxication is available. This review focuses on the drugs under development. In particular, some examples are reviewed to demonstrate the proof of concept of antibody-based therapy. Chemical inhibitors, small proteins, and vaccines can serve as alternatives to antibodies or may be used in combination with antibodies.
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Affiliation(s)
- Christine Rasetti-Escargueil
- Unité des Bactéries Anaérobies et Toxines, Institut Pasteur, 25 Avenue du Docteur Roux, 75015 Paris, France
- Correspondence:
| | - Arnaud Avril
- Unité Immunopathologies, Département Microbiologie et Maladies Infectieuses, Institut de Recherche Biomédicale des Armées, 91220 Brétigny-sur-Orge, France
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5
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Ricin toxin and its neutralizing antibodies: A review. Toxicon 2022; 214:47-53. [PMID: 35595086 DOI: 10.1016/j.toxicon.2022.05.005] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2022] [Revised: 05/10/2022] [Accepted: 05/13/2022] [Indexed: 11/22/2022]
Abstract
Ricin toxin (RT) belongs to the ribosome-inactivating protein (RIP) family of toxins and is considered to be a moderate threat by the US Center of Disease Control and Prevention (CDC). RT poses a great potential threat to the public, but there has been a lack of effective treatment options so far. Over the past few decades, researches on the prevention and treatment of RT poisoning have been investigated, among which neutralizing antibodies targeting RT specifically have always been a research hotspot. In this review, we have summarized the mechanism of action of RT, the research results and the design strategies of RT neutralizing antibodies, and discussed the key issues in the development of RT neutralizing antibody researches.
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Rudolph MJ, Poon AY, Kavaliauskiene S, Myrann AG, Reynolds-Peterson C, Davis SA, Sandvig K, Vance DJ, Mantis NJ. Structural Analysis of Toxin-Neutralizing, Single-Domain Antibodies that Bridge Ricin's A-B Subunit Interface. J Mol Biol 2021; 433:167086. [PMID: 34089718 DOI: 10.1016/j.jmb.2021.167086] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2021] [Revised: 05/18/2021] [Accepted: 05/27/2021] [Indexed: 01/20/2023]
Abstract
Ricin toxin kills mammalian cells with notorious efficiency. The toxin's B subunit (RTB) is a Gal/GalNAc-specific lectin that attaches to cell surfaces and promotes retrograde transport of ricin's A subunit (RTA) to the trans Golgi network (TGN) and endoplasmic reticulum (ER). RTA is liberated from RTB in the ER and translocated into the cell cytoplasm, where it functions as a ribosome-inactivating protein. While antibodies against ricin's individual subunits have been reported, we now describe seven alpaca-derived, single-domain antibodies (VHHs) that span the RTA-RTB interface, including four Tier 1 VHHs with IC50 values <1 nM. Crystal structures of each VHH bound to native ricin holotoxin revealed three different binding modes, based on contact with RTA's F-G loop (mode 1), RTB's subdomain 2γ (mode 2) or both (mode 3). VHHs in modes 2 and 3 were highly effective at blocking ricin attachment to HeLa cells and immobilized asialofetuin, due to framework residues (FR3) that occupied the 2γ Gal/GalNAc-binding pocket and mimic ligand. The four Tier 1 VHHs also interfered with intracellular functions of RTB, as they neutralized ricin in a post-attachment cytotoxicity assay (e.g., the toxin was bound to cell surfaces before antibody addition) and reduced the efficiency of toxin transport to the TGN. We conclude that the RTA-RTB interface is a target of potent toxin-neutralizing antibodies that interfere with both extracellular and intracellular events in ricin's cytotoxic pathway.
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Affiliation(s)
| | - Amanda Y Poon
- Department of Biomedical Sciences, University at Albany, Albany, NY, USA; Division of Infectious Diseases, Wadsworth Center, New York State Department of Health, Albany, NY, USA
| | - Simona Kavaliauskiene
- Department of Molecular Cell Biology, Institute for Cancer Research, The Norwegian Radium Hospital, Oslo University Hospital, Montebello, Oslo, Norway
| | - Anne Grethe Myrann
- Department of Molecular Cell Biology, Institute for Cancer Research, The Norwegian Radium Hospital, Oslo University Hospital, Montebello, Oslo, Norway
| | - Claire Reynolds-Peterson
- Division of Infectious Diseases, Wadsworth Center, New York State Department of Health, Albany, NY, USA
| | - Simon A Davis
- New York Structural Biology Center, New York, NY, USA
| | - Kirsten Sandvig
- Department of Molecular Cell Biology, Institute for Cancer Research, The Norwegian Radium Hospital, Oslo University Hospital, Montebello, Oslo, Norway; Department of Biosciences, University of Oslo, Oslo, Norway
| | - David J Vance
- Division of Infectious Diseases, Wadsworth Center, New York State Department of Health, Albany, NY, USA
| | - Nicholas J Mantis
- Division of Infectious Diseases, Wadsworth Center, New York State Department of Health, Albany, NY, USA.
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Orsini Delgado ML, Avril A, Prigent J, Dano J, Rouaix A, Worbs S, Dorner BG, Rougeaux C, Becher F, Fenaille F, Livet S, Volland H, Tournier JN, Simon S. Ricin Antibodies' Neutralizing Capacity against Different Ricin Isoforms and Cultivars. Toxins (Basel) 2021; 13:100. [PMID: 33573016 PMCID: PMC7911099 DOI: 10.3390/toxins13020100] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/25/2020] [Revised: 01/21/2021] [Accepted: 01/25/2021] [Indexed: 12/11/2022] Open
Abstract
Ricin, a highly toxic protein from Ricinus communis, 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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Affiliation(s)
- Maria Lucia Orsini Delgado
- Paris-Saclay University, CEA, INRAE, Medicines and Healthcare Technologies Department (DMTS), SPI, 91191 Gif-sur-Yvette, France; (J.P.); (J.D.); (A.R.); (F.B.); (F.F.); (S.L.); (H.V.)
| | - Arnaud Avril
- Microbiology and Infectious Diseases Department, Anti-Infectious Biotherapies and Immunity Unit, Army Biomedical Research Institute, 91220 Brétigny-sur-Orge, France; (A.A.); (C.R.); (J.-N.T.)
| | - Julie Prigent
- Paris-Saclay University, CEA, INRAE, Medicines and Healthcare Technologies Department (DMTS), SPI, 91191 Gif-sur-Yvette, France; (J.P.); (J.D.); (A.R.); (F.B.); (F.F.); (S.L.); (H.V.)
| | - Julie Dano
- Paris-Saclay University, CEA, INRAE, Medicines and Healthcare Technologies Department (DMTS), SPI, 91191 Gif-sur-Yvette, France; (J.P.); (J.D.); (A.R.); (F.B.); (F.F.); (S.L.); (H.V.)
| | - Audrey Rouaix
- Paris-Saclay University, CEA, INRAE, Medicines and Healthcare Technologies Department (DMTS), SPI, 91191 Gif-sur-Yvette, France; (J.P.); (J.D.); (A.R.); (F.B.); (F.F.); (S.L.); (H.V.)
| | - Sylvia Worbs
- Biological Toxins, Centre for Biological Threats and Special Pathogens, Robert Koch Institute (RKI), 13353 Berlin, Germany; (S.W.); (B.G.D.)
| | - Brigitte G. Dorner
- Biological Toxins, Centre for Biological Threats and Special Pathogens, Robert Koch Institute (RKI), 13353 Berlin, Germany; (S.W.); (B.G.D.)
| | - Clémence Rougeaux
- Microbiology and Infectious Diseases Department, Anti-Infectious Biotherapies and Immunity Unit, Army Biomedical Research Institute, 91220 Brétigny-sur-Orge, France; (A.A.); (C.R.); (J.-N.T.)
| | - François Becher
- Paris-Saclay University, CEA, INRAE, Medicines and Healthcare Technologies Department (DMTS), SPI, 91191 Gif-sur-Yvette, France; (J.P.); (J.D.); (A.R.); (F.B.); (F.F.); (S.L.); (H.V.)
| | - François Fenaille
- Paris-Saclay University, CEA, INRAE, Medicines and Healthcare Technologies Department (DMTS), SPI, 91191 Gif-sur-Yvette, France; (J.P.); (J.D.); (A.R.); (F.B.); (F.F.); (S.L.); (H.V.)
| | - Sandrine Livet
- Paris-Saclay University, CEA, INRAE, Medicines and Healthcare Technologies Department (DMTS), SPI, 91191 Gif-sur-Yvette, France; (J.P.); (J.D.); (A.R.); (F.B.); (F.F.); (S.L.); (H.V.)
| | - Hervé Volland
- Paris-Saclay University, CEA, INRAE, Medicines and Healthcare Technologies Department (DMTS), SPI, 91191 Gif-sur-Yvette, France; (J.P.); (J.D.); (A.R.); (F.B.); (F.F.); (S.L.); (H.V.)
| | - Jean-Nicolas Tournier
- Microbiology and Infectious Diseases Department, Anti-Infectious Biotherapies and Immunity Unit, Army Biomedical Research Institute, 91220 Brétigny-sur-Orge, France; (A.A.); (C.R.); (J.-N.T.)
| | - Stéphanie Simon
- Paris-Saclay University, CEA, INRAE, Medicines and Healthcare Technologies Department (DMTS), SPI, 91191 Gif-sur-Yvette, France; (J.P.); (J.D.); (A.R.); (F.B.); (F.F.); (S.L.); (H.V.)
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Whitfield SJ, Padgen DB, Knight S, Gwyther RJ, Holley JL, Clark GC, Green AC. Establishment of a Novel Oral Murine Model of Ricin Intoxication and Efficacy Assessment of Ovine Ricin Antitoxins. Toxins (Basel) 2020; 12:E784. [PMID: 33302573 PMCID: PMC7764460 DOI: 10.3390/toxins12120784] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2020] [Revised: 11/25/2020] [Accepted: 12/04/2020] [Indexed: 11/25/2022] Open
Abstract
Ricin, produced from the castor beans of Ricinus communis, is a cytotoxin that exerts its action by inactivating ribosomes and causing cell death. Accidental (e.g., ingestion of castor beans) and/or intentional (e.g., suicide) exposure to ricin through the oral route is an area of concern from a public health perspective and no current licensed medical interventions exist to protect from the action of the toxin. Therefore, we examined the oral toxicity of ricin in Balb/C mice and developed a robust food deprivation model of ricin oral intoxication that has enabled the assessment of potential antitoxin treatments. A lethal oral dose was identified and mice were found to succumb to the toxin within 48 h of exposure. We then examined whether a despeciated ovine F(ab')2 antibody fragment, that had previously been demonstrated to protect mice from exposure to aerosolised ricin, could also protect against oral intoxication. Mice were challenged orally with an LD99 of ricin, and 89 and 44% of mice exposed to this otherwise lethal exposure survived after receiving either the parent anti-ricin IgG or F(ab')2, respectively. Combined with our previous work, these results further highlight the benefit of ovine-derived polyclonal antibody antitoxin in providing post-exposure protection against ricin intoxication.
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Affiliation(s)
- Sarah J. Whitfield
- CBR Division, Dstl-Porton Down, Salisbury SP4 0JQ, UK; (D.B.P.); (S.K.); (R.J.G.); (J.L.H.); (G.C.C.); (A.C.G.)
| | - Debbie B. Padgen
- CBR Division, Dstl-Porton Down, Salisbury SP4 0JQ, UK; (D.B.P.); (S.K.); (R.J.G.); (J.L.H.); (G.C.C.); (A.C.G.)
| | - Simon Knight
- CBR Division, Dstl-Porton Down, Salisbury SP4 0JQ, UK; (D.B.P.); (S.K.); (R.J.G.); (J.L.H.); (G.C.C.); (A.C.G.)
| | - Robert J. Gwyther
- CBR Division, Dstl-Porton Down, Salisbury SP4 0JQ, UK; (D.B.P.); (S.K.); (R.J.G.); (J.L.H.); (G.C.C.); (A.C.G.)
| | - Jane L. Holley
- CBR Division, Dstl-Porton Down, Salisbury SP4 0JQ, UK; (D.B.P.); (S.K.); (R.J.G.); (J.L.H.); (G.C.C.); (A.C.G.)
| | - Graeme C. Clark
- CBR Division, Dstl-Porton Down, Salisbury SP4 0JQ, UK; (D.B.P.); (S.K.); (R.J.G.); (J.L.H.); (G.C.C.); (A.C.G.)
- Institute of Infection and Global Health, University of Liverpool, IC2 Building, Liverpool L3 5RF, UK
| | - A. Christopher Green
- CBR Division, Dstl-Porton Down, Salisbury SP4 0JQ, UK; (D.B.P.); (S.K.); (R.J.G.); (J.L.H.); (G.C.C.); (A.C.G.)
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9
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Vance DJ, Poon AY, Mantis NJ. Sites of vulnerability on ricin B chain revealed through epitope mapping of toxin-neutralizing monoclonal antibodies. PLoS One 2020; 15:e0236538. [PMID: 33166282 PMCID: PMC7652295 DOI: 10.1371/journal.pone.0236538] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2020] [Accepted: 10/26/2020] [Indexed: 12/16/2022] Open
Abstract
Ricin toxin's B subunit (RTB) is a multifunctional galactose (Gal)-/N-acetylgalactosamine (GalNac)-specific lectin that promotes uptake and intracellular trafficking of ricin's ribosome-inactivating subunit (RTA) into mammalian cells. Structurally, RTB consists of two globular domains (RTB-D1, RTB-D2), each divided into three homologous sub-domains (α, β, γ). The two carbohydrate recognition domains (CRDs) are situated on opposite sides of RTB (sub-domains 1α and 2γ) and function non-cooperatively. Previous studies have revealed two distinct classes of toxin-neutralizing, anti-RTB monoclonal antibodies (mAbs). Type I mAbs, exemplified by SylH3, inhibit (~90%) toxin attachment to cell surfaces, while type II mAbs, epitomized by 24B11, interfere with intracellular toxin transport between the plasma membrane and the trans-Golgi network (TGN). Localizing the epitopes recognized by these two classes of mAbs has proven difficult, in part because of RTB's duplicative structure. To circumvent this problem, RTB-D1 and RTB-D2 were expressed as pIII fusion proteins on the surface of filamentous phage M13 and subsequently used as "bait" in mAb capture assays. We found that SylH3 captured RTB-D1 (but not RTB-D2) in a dose-dependent manner, while 24B11 captured RTB-D2 (but not RTB-D1) in a dose-dependent manner. We confirmed these domain assignments by competition studies with an additional 8 RTB-specific mAbs along with a dozen a single chain antibodies (VHHs). Collectively, these results demonstrate that type I and type II mAbs segregate on the basis of domain specificity and suggest that RTB's two domains may contribute to distinct steps in the intoxication pathway.
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Affiliation(s)
- David J. Vance
- Division of Infectious Disease, New York State Department of Health,Wadsworth Center, Albany, NY, United States of America
| | - Amanda Y. Poon
- Department of Biomedical Sciences, University at Albany School of Public Health, Albany, NY, United States of America
| | - Nicholas J. Mantis
- Division of Infectious Disease, New York State Department of Health,Wadsworth Center, Albany, NY, United States of America
- Department of Biomedical Sciences, University at Albany School of Public Health, Albany, NY, United States of America
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10
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Slyke GV, Ehrbar DJ, Doering J, Yates JL, Vitetta ES, Donini O, Mantis NJ. Endpoint and epitope-specific antibody responses as correlates of vaccine-mediated protection of mice against ricin toxin. Vaccine 2020; 38:6721-6729. [PMID: 32891474 DOI: 10.1016/j.vaccine.2020.08.047] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2020] [Revised: 08/11/2020] [Accepted: 08/18/2020] [Indexed: 12/17/2022]
Abstract
The successful licensure of vaccines for biodefense is contingent upon the availability of well-established correlates of protection (CoP) in at least two animal species that can be applied to humans, without the need to assess efficacy in the clinic. In this report we describe a multivariate model that combines pre-challenge serum antibody endpoint titers (EPT) and values derived from an epitope profiling immune-competition capture (EPICC) assay as a predictor in mice of vaccine-mediated immunity against ricin toxin (RT), a Category B biothreat. EPICC is a modified competition ELISA in which serum samples from vaccinated mice were assessed for their ability to inhibit the capture of soluble, biotinylated (b)-RT by a panel of immobilized monoclonal antibodies (mAbs) directed against four immunodominant toxin-neutralizing regions on the enzymatic A chain (RTA) of RT. In a test cohort of mice (n = 40) vaccinated with suboptimal doses of the RTA subunit vaccine, RiVax®, we identified two mAbs, PB10 and SyH7, which had EPICC inhibition values in pre-challenge serum samples that correlated with survival following a challenge with 5 × LD50 of RT administered by intraperitoneal (IP) injection. Analysis of a larger cohort of mice (n = 645) revealed that a multivariate model combining endpoint titers and EPICC values for PB10 and SyH7 as predictive variables had significantly higher statistical power than any one of the independent variables alone. Establishing the correlates of vaccine-mediated protection in mice represents an important steppingstone in the development of RiVax® as a medical countermeasure under the United States Food and Drug Administration's "Animal Rule."
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Affiliation(s)
- Greta Van Slyke
- Division of Infectious Disease, Wadsworth Center, New York State Department of Health, Albany, NY 12208, United States
| | - Dylan J Ehrbar
- Division of Infectious Disease, Wadsworth Center, New York State Department of Health, Albany, NY 12208, United States
| | - Jennifer Doering
- Division of Infectious Disease, Wadsworth Center, New York State Department of Health, Albany, NY 12208, United States
| | - Jennifer L Yates
- Division of Infectious Disease, Wadsworth Center, New York State Department of Health, Albany, NY 12208, United States
| | - Ellen S Vitetta
- Department of Immunology and Microbiology, University of Texas Southwestern Medical School, Dallas, TX, United States
| | | | - Nicholas J Mantis
- Division of Infectious Disease, Wadsworth Center, New York State Department of Health, Albany, NY 12208, United States.
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