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Jones PJH, Shamloo M, MacKay DS, Rideout TC, Myrie SB, Plat J, Roullet JB, Baer DJ, Calkins KL, Davis HR, Barton Duell P, Ginsberg H, Gylling H, Jenkins D, Lütjohann D, Moghadasian M, Moreau RA, Mymin D, Ostlund RE, Ras RT, Ochoa Reparaz J, Trautwein EA, Turley S, Vanmierlo T, Weingärtner O. Progress and perspectives in plant sterol and plant stanol research. Nutr Rev 2019; 76:725-746. [PMID: 30101294 DOI: 10.1093/nutrit/nuy032] [Citation(s) in RCA: 38] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Current evidence indicates that foods with added plant sterols or stanols can lower serum levels of low-density lipoprotein cholesterol. This review summarizes the recent findings and deliberations of 31 experts in the field who participated in a scientific meeting in Winnipeg, Canada, on the health effects of plant sterols and stanols. Participants discussed issues including, but not limited to, the health benefits of plant sterols and stanols beyond cholesterol lowering, the role of plant sterols and stanols as adjuncts to diet and drugs, and the challenges involved in measuring plant sterols and stanols in biological samples. Variations in interindividual responses to plant sterols and stanols, as well as the personalization of lipid-lowering therapies, were addressed. Finally, the clinical aspects and treatment of sitosterolemia were reviewed. Although plant sterols and stanols continue to offer an efficacious and convenient dietary approach to cholesterol management, long-term clinical trials investigating the endpoints of cardiovascular disease are still lacking.
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Affiliation(s)
- Peter J H Jones
- Richardson Centre for Functional Foods and Nutraceuticals, University of Manitoba, Winnipeg, Manitoba, Canada.,Department of Food and Human Nutritional Sciences, University of Manitoba, Winnipeg, Manitoba, Canada
| | - Maryam Shamloo
- Department of Food and Human Nutritional Sciences, University of Manitoba, Winnipeg, Manitoba, Canada.,George and Fay Yee Centre for Healthcare Innovation, University of Manitoba, Winnipeg, Manitoba, Canada
| | - Dylan S MacKay
- George and Fay Yee Centre for Healthcare Innovation, University of Manitoba, Winnipeg, Manitoba, Canada
| | - Todd C Rideout
- Department of Exercise and Nutrition Sciences, University of Buffalo, Buffalo, New York, USA
| | - Semone B Myrie
- Richardson Centre for Functional Foods and Nutraceuticals, University of Manitoba, Winnipeg, Manitoba, Canada.,Department of Food and Human Nutritional Sciences, University of Manitoba, Winnipeg, Manitoba, Canada
| | - Jogchum Plat
- Department of Human Biology, Maastricht University, Maastricht, the Netherlands
| | - Jean-Baptiste Roullet
- Division of Metabolism, Child Development and Rehabilitation Center-Portland, Department of Pediatrics, Oregon Health & Science University, Portland, Oregon, USA
| | - David J Baer
- US Department of Agriculture, Agricultural Research Service, Beltsville Human Nutrition Research Center, Beltsville, Maryland, USA
| | - Kara L Calkins
- Department of Pediatrics, Division of Neonatology, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, California, USA; and the UCLA Mattel's Children's Hospital, Los Angeles, California, USA
| | | | - P Barton Duell
- Knight Cardiovascular Institute, Oregon Health & Science University, Portland, Oregon, USA
| | - Henry Ginsberg
- Institute of Human Nutrition, Columbia University Irving Medical Center, New York, New York, USA
| | - Helena Gylling
- University of Helsinki and the Helsinki University Central Hospital, Helsinki, Finland
| | - David Jenkins
- Department of Nutritional Sciences, University of Toronto, Toronto, Ontario, Canada; and the Clinical Nutrition and Risk Factor Modification Centre, St. Michael's Hospital, Toronto, Ontario, Canada
| | - Dieter Lütjohann
- Institute for Clinical Chemistry and Clinical Pharmacology, University of Bonn, Bonn, Germany
| | - Mohammad Moghadasian
- Department of Food and Human Nutritional Sciences, University of Manitoba, Winnipeg, Manitoba, Canada
| | - Robert A Moreau
- Eastern Regional Research Center, US Department of Agriculture, Agricultural Research Service, Wyndmoor, Pennsylvania, USA
| | - David Mymin
- Department of Internal Medicine, University of Manitoba, Winnipeg, Manitoba, Canada
| | - Richard E Ostlund
- Division of Endocrinology, Metabolism and Lipid Research, Washington University, St Louis, USA
| | - Rouyanne T Ras
- Unilever Research & Development Vlaardingen, Vlaardingen, the Netherlands
| | | | - Elke A Trautwein
- Unilever Research & Development Vlaardingen, Vlaardingen, the Netherlands
| | | | - Tim Vanmierlo
- Department of Immunology and Biochemistry, Biomedical Research Institute, Hasselt University, Hasselt, Belgium
| | - Oliver Weingärtner
- Klinik für Innere Medizin I, Universitätsklinikum Jena, Friedrich-Schiller-Universität Jena, Jena, Germany; Abteilung für Kardiologie, Klinikum Oldenburg, European Medical School Oldenburg-Groningen, Oldenburg, Germany
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Das S, Mohakud NK, Suar M, Sahu BR. Vaccine development for enteric bacterial pathogens: Where do we stand? Pathog Dis 2019; 76:5040763. [PMID: 30052916 DOI: 10.1093/femspd/fty057] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2018] [Accepted: 06/19/2018] [Indexed: 01/06/2023] Open
Abstract
Gut infections triggered by pathogenic bacteria lead to most frequently occurring diarrhea in humans accounting for million deaths annually. Currently, only a few licensed vaccines are available against these pathogens for mostly travelers moving to diarrheal endemic areas. Besides commercialized vaccines, there are many formulations that are either under clinical or pre-clinical stages of development and despite several efforts to improve safety, immunogenicity and efficacy, none of them can confer long-term protective immunity, for which repeated booster doses are always recommended. Further in many countries, financial, social and political constraints have jeopardized vaccine development program against these pathogens that enforce us to gather knowledge on safety, tolerability, immunogenicity and protective efficacy regarding the same. In this review, we analyze safety and efficacy issues of vaccines against five major gut bacteria causing enteric infections. The article also simultaneously describes several barriers for vaccine development and further discusses possible strategies to enhance immunogenicity and efficacy.
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Affiliation(s)
- Susmita Das
- Infection Biology Lab, KIIT School of Biotechnology, Campus XI, Bhubaneswar 751024, India
| | - Nirmal K Mohakud
- Department of Pediatrics, Kalinga Institute of Medical Sciences, Patia, Bhubaneswar 751024, India
| | - Mrutyunjay Suar
- Infection Biology Lab, KIIT School of Biotechnology, Campus XI, Bhubaneswar 751024, India
| | - Bikash R Sahu
- Infection Biology Lab, KIIT School of Biotechnology, Campus XI, Bhubaneswar 751024, India
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Abstract
This chapter reviews papers mostly written since 2005 that report results using live attenuated bacterial vectors to deliver after administration through mucosal surfaces, protective antigens, and DNA vaccines, encoding protective antigens to induce immune responses and/or protective immunity to pathogens that colonize on or invade through mucosal surfaces. Papers that report use of such vaccine vector systems for parenteral vaccination or to deal with nonmucosal pathogens or do not address induction of mucosal antibody and/or cellular immune responses are not reviewed.
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Mertensotto MJ, Drees JJ, Augustin LB, Schottel JL, Saltzman DA. Expression of periplasmic chaperones in Salmonella Typhimurium reduces its viability in vivo. Curr Microbiol 2014; 70:433-5. [PMID: 25432864 DOI: 10.1007/s00284-014-0739-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2014] [Accepted: 11/05/2014] [Indexed: 11/26/2022]
Abstract
The efficacy of live attenuated bacterial vectors is dependent upon the fine-tuning of a strain's immunogenicity and its virulence. Strains are often engineered to deliver heterologous antigens, but soluble expression of recombinant proteins can be troublesome. Therefore, secretion systems or chaperone proteins are routinely used to assist in attaining high levels of functional, soluble protein production. However, the effects of chaperone expression on the virulence of attenuated bacterial vectors have not been previously reported. In anticipation of utilizing periplasmic chaperone proteins to facilitate soluble production of immunomodulatory proteins in an attenuated strain of Salmonella Typhimurium, the production of the chaperones was tested for their effect on both culture growth and bacterial persistence in mouse tissues. Although no effect on growth of the bacteria was observed in vitro, the increased expression of the periplasmic chaperones resulted in over-attenuation of the Salmonella in vivo.
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Celikkol-Aydin S, Suo Z, Yang X, Ince B, Avci R. Sharp transition in the immunoimmobilization of E. coli O157:H7. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2014; 30:7755-7761. [PMID: 24911628 DOI: 10.1021/la501545n] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
This work focuses on immobilization of living enterohemorrhagic Escherichia coli O157:H7 on a gold surface as a function of the concentration of antibody tethered to the surface in the physiological environment of the organisms. Experiments are conducted using antibodies raised against bacterial surface lipopolysaccharides (LPS) tethered to gold-coated silicon wafers at surface concentrations spanning a range from submonolayers of antibodies to full coverage, an estimated 1 antibody per ∼100 nm(2). A careful optimization of surface chemistry is conducted to obtain the most efficient tethering of the antibodies to the surface. The mechanism of immobilizing the bacteria is antibody-antigen interactions between the tethered antibodies on the surface and the bacterial surface LPS firmly attached to the bacteria. This type of attachment is known as immunoimmobilization. The experiments suggest no noticeable bacterial attachment until the surface antibody concentration reaches ∼70% of a full monolayer of coverage. Above this critical antibody density, a sharp increase in immunoimmobilized bacteria is observed as they populate nearly 80% to 100% of the available surface area, reaching ∼1.2 cells/10 μm(2). This sharp increase in population is tentatively explained in terms of the minimum number of antibody-antigen interactions required per bacterium to immobilize the cell. This critical number is estimated to be ∼6000-8000 antibodies per bacterium (having a 1 μm(2) footprint on the surface) under the assumption that a full monolayer of antibodies is about 1 antibody per ∼100 nm(2). However, the large majority of the 6000-8000 antibodies are not expected to participate in antibody-antigen interactions, in that the loose LPS in solution will saturate many of these antibodies before bacteria have a chance to interact with them. Furthermore, the geometric considerations will further restrict the majority of the active antibodies from interacting with the surface antigens of the cell, reducing its effective contact area with the antibodies considerably.
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Affiliation(s)
- Sukriye Celikkol-Aydin
- Institute of Environmental Sciences, Bogazici University , Bebek, Istanbul 34342, Turkey
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Regulatory T-cell vaccination independent of auto-antigen. Exp Mol Med 2014; 46:e82. [PMID: 24626168 PMCID: PMC3972794 DOI: 10.1038/emm.2014.4] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2013] [Accepted: 12/06/2013] [Indexed: 12/21/2022] Open
Abstract
To date, efforts to treat autoimmune diseases have primarily focused on the disease symptoms rather than on the cause of the disease. In large part, this is attributed to not knowing the responsible auto-antigens (auto-Ags) for driving the self-reactivity coupled with the poor success of treating autoimmune diseases using oral tolerance methods. Nonetheless, if tolerogenic approaches or methods that stimulate regulatory T (Treg) cells can be devised, these could subdue autoimmune diseases. To forward such efforts, our approach with colonization factor antigen I (CFA/I) fimbriae is to establish bystander immunity to ultimately drive the development of auto-Ag-specific Treg cells. Using an attenuated Salmonella vaccine expressing CFA/I fimbriae, fimbriae-specific Treg cells were induced without compromising the vaccine's capacity to protect against travelers' diarrhea or salmonellosis. By adapting the vaccine's anti-inflammatory properties, it was found that it could also dampen experimental inflammatory diseases resembling multiple sclerosis (MS) and rheumatoid arthritis. Because of this bystander effect, disease-specific Treg cells are eventually induced to resolve disease. Interestingly, this same vaccine could elicit the required Treg cell subset for each disease. For MS-like disease, conventional CD25+ Treg cells are stimulated, but for arthritis CD39+ Treg cells are induced instead. This review article will examine the potential of treating autoimmune diseases without having previous knowledge of the auto-Ag using an innocuous antigen to stimulate Treg cells via the production of transforming growth factor-β and interleukin-10.
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Pascual DW, Suo Z, Cao L, Avci R, Yang X. Attenuating gene expression (AGE) for vaccine development. Virulence 2013; 4:384-90. [PMID: 23652809 PMCID: PMC3714130 DOI: 10.4161/viru.24886] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
Live attenuated vaccines are adept in stimulating protective immunity. Methods for generating such vaccines have largely adopted strategies used with Salmonella enterica. Yet, when similar strategies were tested in other gram-negative bacteria, the virulence factors or genes responsible to incapacitate Salmonella often failed in providing the desired outcome. Consequently, conventional live vaccines rely on prior knowledge of the pathogen's virulence factors to successfully attenuate them. This can be problematic since such bacterial pathogens normally harbor thousands of genes. To circumvent this problem, we found that overexpression of bacterial appendages, e.g., fimbriae, capsule, and flagella, could successfully attenuate wild-type (wt) Salmonella enterica serovar Typhimurium. Further analysis revealed these attenuated Salmonella strains conferred protection against wt S. Typhimurium challenge as effectively as genetically defined Salmonella vaccines. We refer to this strategy as attenuating gene expression (AGE), a simple efficient approach in attenuating bacterial pathogens, greatly facilitating the construction of live vaccines.
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Affiliation(s)
- David W Pascual
- Department of Infectious Diseases and Pathology, College of Veterinary Medicine, University of Florida, Gainesville, FL USA.
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Adhesion protein ApfA of Actinobacillus pleuropneumoniae is required for pathogenesis and is a potential target for vaccine development. CLINICAL AND VACCINE IMMUNOLOGY : CVI 2012; 20:287-94. [PMID: 23269417 DOI: 10.1128/cvi.00616-12] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Actinobacillus pleuropneumoniae is the etiologic agent of porcine pleuropneumonia, which causes serious economic losses in the pig farming industry worldwide. Due to a lack of knowledge of its virulence factors and a lack of effective vaccines able to confer cross-serotype protection, it is difficult to place this disease under control. By analyzing its genome sequences, we found that type IV fimbrial subunit protein ApfA is highly conserved among different serotypes of A. pleuropneumoniae. Our study shows that ApfA is an adhesin since its expression was greatly upregulated (135-fold) upon contact with host cells, while its deletion mutant attenuated its capability of adhesion. The inactivation of apfA dramatically reduced the ability of A. pleuropneumoniae to colonize mouse lung, suggesting that apfA is a virulence factor. Purified recombinant ApfA elicited an elevated humoral immune response and conferred robust protection against challenges with A. pleuropneumoniae serovar 1 strain 4074 and serovar 7 strain WF83 in mice. Importantly, the anti-ApfA serum conferred significant protection against both serovar 1 and serovar 7 in mice. These studies indicate that ApfA promotes virulence through attachment to host cells, and its immunogenicity renders it a promising novel subunit vaccine candidate against infection with A. pleuropneumoniae.
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Yang X, Thornburg T, Suo Z, Jun S, Robison A, Li J, Lim T, Cao L, Hoyt T, Avci R, Pascual DW. Flagella overexpression attenuates Salmonella pathogenesis. PLoS One 2012; 7:e46828. [PMID: 23056473 PMCID: PMC3463563 DOI: 10.1371/journal.pone.0046828] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2012] [Accepted: 09/05/2012] [Indexed: 11/18/2022] Open
Abstract
Flagella are cell surface appendages involved in a number of bacterial behaviors, such as motility, biofilm formation, and chemotaxis. Despite these important functions, flagella can pose a liability to a bacterium when serving as potent immunogens resulting in the stimulation of the innate and adaptive immune systems. Previous work showing appendage overexpression, referred to as attenuating gene expression (AGE), was found to enfeeble wild-type Salmonella. Thus, this approach was adapted to discern whether flagella overexpression could induce similar attenuation. To test its feasibility, flagellar filament subunit FliC and flagellar regulon master regulator FlhDC were overexpressed in Salmonella enterica serovar Typhimurium wild-type strain H71. The results show that the expression of either FliC or FlhDC alone, and co-expression of the two, significantly attenuates Salmonella. The flagellated bacilli were unable to replicate within macrophages and thus were not lethal to mice. In-depth investigation suggests that flagellum-mediated AGE was due to the disruptive effects of flagella on the bacterial membrane, resulting in heightened susceptibilities to hydrogen peroxide and bile. Furthermore, flagellum-attenuated Salmonella elicited elevated immune responses to Salmonella presumably via FliC's adjuvant effect and conferred robust protection against wild-type Salmonella challenge.
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Affiliation(s)
- Xinghong Yang
- Department of Immunology & Infectious Diseases, Montana State University, Bozeman, Montana, United States of America.
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Cao L, Suo Z, Lim T, Jun S, Deliorman M, Riccardi C, Kellerman L, Avci R, Yang X. Role of overexpressed CFA/I fimbriae in bacterial swimming. Phys Biol 2012; 9:036005. [PMID: 22562964 DOI: 10.1088/1478-3975/9/3/036005] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Enterotoxigenic Escherichia coli CFA/I is a protective antigen and has been overexpressed in bacterial vectors, such as Salmonella Typhimurium H683, to generate vaccines. Effects that overexpressed CFA/I may engender on the bacterial host remain largely unexplored. To investigate, we constructed a high CFA/I expression strain, H683-pC2, and compared it to a low CFA/I expression strain, H683-pC, and to a non-CFA/I expression strain, H683-pY. The results showed that H683-pC2 was less able to migrate into semisolid agar (0.35%) than either H683-pC or H683-pY. Bacteria that migrated showed motility halo sizes of H683-pC2 < H683-pC < H683-pY. In the liquid culture media, H683-pC2 cells precipitated to the bottom of the tube, while those of H683-pY did not. In situ imaging revealed that H683-pC2 bacilli tended to auto-agglutinate within the semisolid agar, while H683-pY bacilli did not. When the cfaBE fimbrial fiber encoding genes were deleted from pC2, the new plasmid, pC2(-), significantly recovered bacterial swimming capability. Our study highlights the negative impact of overexpressed CFA/I fimbriae on bacterial swimming motility.
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Affiliation(s)
- Ling Cao
- Immunology & Infectious Diseases, Montana State University, Bozeman, MT 59717-3610, USA
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Cao L, Lim T, Jun S, Thornburg T, Avci R, Yang X. Vulnerabilities in Yersinia pestis caf operon are unveiled by a Salmonella vector. PLoS One 2012; 7:e36283. [PMID: 22558420 PMCID: PMC3340336 DOI: 10.1371/journal.pone.0036283] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2011] [Accepted: 03/28/2012] [Indexed: 11/18/2022] Open
Abstract
During infection, Yersinia pestis uses its F1 capsule to enhance survival and cause virulence to mammalian host. Since F1 is produced in large quantities and secreted into the host tissues, it also serves as a major immune target. To hold this detrimental effect under proper control, Y. pestis expresses the caf operon (encoding the F1 capsule) in a temperature-dependent manner. However, additional properties of the caf operon limit its expression. By overexpressing the caf operon in wild-type Salmonella enterica serovar Typhimurium under a potent promoter, virulence of Salmonella was greatly attenuated both in vitro and in vivo. In contrast, expression of the caf operon under the regulation of its native promoter exhibited negligible impairment of Salmonellae virulence. In-depth investigation revealed all individual genes in the caf operon attenuated Salmonella when overexpressed. The deleterious effects of caf operon and the caf individual genes were further confirmed when they were overexpressed in Y. pestis KIM6+. This study suggests that by using a weak inducible promoter, the detrimental effects of the caf operon are minimally manifested in Y. pestis. Thus, through tight regulation of the caf operon, Y. pestis precisely balances its capsular anti-phagocytic properties with the detrimental effects of caf during interaction with mammalian host.
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Affiliation(s)
- Ling Cao
- Immunology and Infectious Diseases, Montana State University, Bozeman, Montana, United States of America
| | - Timothy Lim
- Immunology and Infectious Diseases, Montana State University, Bozeman, Montana, United States of America
| | - SangMu Jun
- Immunology and Infectious Diseases, Montana State University, Bozeman, Montana, United States of America
| | - Theresa Thornburg
- Immunology and Infectious Diseases, Montana State University, Bozeman, Montana, United States of America
| | - Recep Avci
- Imaging and Chemical Analysis Laboratory, Department of Physics, Montana State University, Bozeman, Montana, United States of America
| | - Xinghong Yang
- Immunology and Infectious Diseases, Montana State University, Bozeman, Montana, United States of America
- * E-mail:
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Goller CC, Seed PC. Coming of AGE. Virulence 2012; 3:12-4. [DOI: 10.4161/viru.3.1.19087] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
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