Immunoassay for Capsular Antigen of Bacillus anthracis Enables Rapid Diagnosis in a Rabbit Model of Inhalational Anthrax

There is no author summary for this article yet. Authors can add summaries to their articles on ScienceOpen to make them more accessible to a non-specialist audience.

Abstract

Inhalational anthrax is a serious biothreat. Effective antibiotic treatment of inhalational anthrax requires early diagnosis; the further the disease has progressed, the less the likelihood for cure. Current means for diagnosis such as blood culture require several days to a result and require advanced laboratory infrastructure. An alternative approach to diagnosis is detection of a Bacillus anthracis antigen that is shed into blood and can be detected by rapid immunoassay. The goal of the study was to evaluate detection of poly-γ-D-glutamic acid (PGA), the capsular antigen of B. anthracis, as a biomarker surrogate for blood culture in a rabbit model of inhalational anthrax. The mean time to a positive blood culture was 26 ± 5.7 h (mean ± standard deviation), whereas the mean time to a positive ELISA was 22 ± 4.2 h; P = 0.005 in comparison with blood culture. A lateral flow immunoassay was constructed for detection of PGA in plasma at concentrations of less than 1 ng PGA/ml. Use of the lateral flow immunoassay for detection of PGA in the rabbit model found that antigen was detected somewhat earlier than the earliest time point at which the blood culture became positive. The low cost, ease of use, and rapid time to result of the lateral flow immunoassay format make an immunoassay for PGA a viable surrogate for blood culture for detection of infection in individuals who have a likelihood of exposure to B. anthracis.

Related collections

Most cited references 11

Record: found
Abstract: found
Article: not found

The pathology of experimental anthrax in rabbits exposed by inhalation and subcutaneous inoculation.

G Zaucha, L M Pitt, J. Estep … (1998)

Although rhesus monkeys are considered to be an appropriate model for inhalational anthrax in humans, an alternative for vaccine and therapeutic efficacy studies is desirable. This study characterized the pathology of lethal anthrax in rabbits challenged by subcutaneous inoculation and aerosol exposure. New Zealand white rabbits were exposed by subcutaneous inoculation or aerosol to lethal doses of Bacillus anthracis spores. The pathology of anthrax in rabbits exposed by either route was similar, with principal findings occurring in the spleen, lymph nodes, lungs, gastrointestinal tract, and adrenal glands. The cardinal changes were hemorrhage, edema, and necrosis, with bacilli and limited leukocytic infiltration. Features that depended on the route of exposure included mediastinitis in aerosol-exposed rabbits, a primary dermal lesion after subcutaneous inoculation, and differences in the pattern of lymph node involvement. Lesions observed in rabbits were comparable to those of inhalational anthrax in humans and rhesus monkeys. Noteworthy differences included the lack of leukocytic infiltration in brain and meningeal lesions, the relatively mild mediastinal lesions, and a lower incidence of anthrax-related pneumonia in rabbits compared with humans. These differences may be attributed to the greater susceptibility of rabbits to anthrax. Increased susceptibility is associated with both reduced leukocytic response to the bacilli and a more rapid progression to death, which further limits development of leukocytic infiltrates in response to the basic lesions of hemorrhage and necrosis. Primary pneumonic foci of inhalational anthrax, which may be influenced by preexisting pulmonary lesions in humans, were not observed in our rabbits, which were free of preexisting pulmonary disease. Anthrax in rabbits may provide a useful model for evaluating prophylaxis and therapy against inhalational anthrax in humans.

0 comments Cited 32 times – based on 0 reviews      Review now

Bookmark

Record: found
Abstract: found
Article: not found

Pathology of inhalation anthrax in cynomolgus monkeys (Macaca fascicularis).

James Estep, Simao D. Vasconcelos, Steven Babin … (2003)

Anthrax is considered a serious biowarfare and bioterrorism threat because of its high lethality, especially by the inhalation route. Rhesus macaques (Macaca mulatta) are the most commonly used nonhuman primate model of human inhalation anthrax exposure. The nonavailability of rhesus macaques necessitated development of an alternate model for vaccine testing and immunologic studies. This report describes the median lethal dose (LD(50)) and pathology of inhalation anthrax in cynomolgus macaques (Macaca fascicularis). Gross and microscopic tissue changes were reviewed in 14 cynomolgus monkeys that died or were killed after aerosol exposure of spores of Bacillus anthracis (Ames strain). The LD(50) and 95% confidence intervals were 61800 (34000 to 110000) colony-forming units. The most common gross lesions were mild splenomegaly, lymph node enlargement, and hemorrhages in various organs, particularly involving the meninges and the lungs. Mediastinitis, manifested as hemorrhage or edema, affected 29% of the monkeys. Microscopically, lymphocytolysis occurred in the intrathoracic lymph nodes and spleens of all animals, and was particularly severe in the spleen and in germinal centers of lymph nodes. Hemorrhages were common in lungs, bronchial lymph nodes, meninges, gastrointestinal tract, and mediastinum. These results demonstrate that the Ames strain of B. anthracis is lethal by the inhalation route in the cynomolgus macaque. The LD(50) of the Ames strain of B. anthracis was within the expected experimental range of previously reported values in the rhesus monkey in an aerosol challenge. The gross and microscopic pathology of inhalation anthrax in the cynomolgus monkey is remarkably similar to that reported in rhesus monkeys and humans. The results of this study are important for the establishment of an alternative nonhuman primate model for evaluation of medical countermeasures against inhalational anthrax.

0 comments Cited 30 times – based on 0 reviews      Review now

Bookmark

Record: found
Abstract: found
Article: not found

mAbs to Bacillus anthracis capsular antigen for immunoprotection in anthrax and detection of antigenemia.

T R Kozel, W Murphy, S. Brandt … (2004)

Bacillus anthracis is surrounded by an antiphagocytic polypeptide capsule composed of poly gamma-D-glutamic acid (gammaDPGA). gammaDPGA has been identified recently as a potential target for vaccine development. Studies of the role of gammaDPGA in disease have been hampered by the poor Ab response to this antigen and the lack of immunochemical reagents. As a consequence, neither the extent of gammaDPGA production during anthrax nor the protective activity of gammaDPGA Abs in inhalation anthrax are known. Here we report production of IgG Abs to gammaDPGA in mice following an immunization regimen using gammaDPGA in combination with agonist mAbs to CD40. mAbs were produced that are specific for gammaDPGA. Passive immunization with gammaDPGA mAbs protected >90% of mice in a pulmonary model of anthrax that was lethal in control mice (P < 0.0001). Use of gammaDPGA mAb in an antigen detection immunoassay found that the appearance of gammaDPGA in serum coincided with the emergence of bacteremia. These studies identify CD40 stimulation as a means for production of Ab and generation of mAbs against a weakly immunogenic antigen and demonstrate that the capsule is an effective target for immunoprotection and for antigen detection in the diagnosis of anthrax.

0 comments Cited 24 times – based on 0 reviews      Review now

Bookmark

All references

Author and article information

Contributors

Ramin M. Hakami: Role: Academic Editor

Journal

Journal ID (nlm-ta): PLoS One

Journal ID (iso-abbrev): PLoS ONE

Journal ID (publisher-id): plos

Journal ID (pmc): plosone

Title: PLoS ONE

Publisher: Public Library of Science (San Francisco, CA USA )

ISSN (Electronic): 1932-6203

Publication date (Electronic): 5 May 2015

Publication date Collection: 2015

Volume: 10

Issue: 5

Electronic Location Identifier: e0126304

Affiliations

[1 ]University of Nevada School of Medicine, Reno, Nevada, United States of America

[2 ]Battelle Biomedical Research Center, Columbus, Ohio, United States of America

[3 ]InBios International, Inc., Seattle, Washington, United States of America

George Mason University, UNITED STATES

Author notes

Competing Interests: TRK is a coinventor of a licensed patent, which has generated no revenue, for compositions and methods of detection, prevention and treatment of anthrax and other infectious diseases. Patent details: 'Detecting bacterial infection by a polyglutamic acid- (PGA-) producing pathogen; administration of a capsular polypeptide of a pathogen of interest and a CD40 agonist; immunization US 7682796 B2.' SR has ownership at InBios International, Inc. and HC, JN and RH are employees of InBios International, Inc. There are no further patents, products in development or marketed products to declare. This does not alter the authors' adherence to all the PLOS ONE policies on sharing data and materials, as detailed online in the guide for authors.

Conceived and designed the experiments: MAG MRP HC JN RLH SR MAH TRK. Performed the experiments: MAG MRP HC JN MAH. Analyzed the data: MAG MAH TRK. Contributed reagents/materials/analysis tools: SR TRK. Wrote the paper: MAG TRK.

* E-mail: tkozel@ 123456medicine.nevada.edu

Article

Publisher ID: PONE-D-14-34046

DOI: 10.1371/journal.pone.0126304

PMC ID: 4420260

PubMed ID: 25942409

SO-VID: d44345bd-9a6c-4416-b500-fd148cdbfc6d

License:

This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited

History

Date received : 30 July 2014

Date accepted : 31 March 2015

Page count

Figures: 3, Tables: 1, Pages: 9

Funding

This study was supported by Public Health Service grants AI059348, AI061200 and AI093365 from the National Institutes of Health ( www.nih.gov). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript. InBios International Inc. provided support in the form of salaries for authors HC, JN, RLH and SR, but did not have any additional role in the study design, data collection and analysis, decision to publish, or preparation of the manuscript. The specific roles of these authors are articulated in the ‘author contributions’ section.

Custom metadata

Data Availability All relevant data are within the paper.

ScienceOpen disciplines: Uncategorized

Data availability:

ScienceOpen disciplines: Uncategorized

Comments

Comment on this article

scite_

Cited by 6

See all cited by

Most referenced authors 85

See all reference authors

Immunoassay for Capsular Antigen of Bacillus anthracis Enables Rapid Diagnosis in a Rabbit Model of Inhalational Anthrax

Read this article at

Abstract

Related collections

PLOS Climate

Most cited references 11

The pathology of experimental anthrax in rabbits exposed by inhalation and subcutaneous inoculation.

Pathology of inhalation anthrax in cynomolgus monkeys (Macaca fascicularis).

mAbs to Bacillus anthracis capsular antigen for immunoprotection in anthrax and detection of antigenemia.

Author and article information

Contributors

Journal

Affiliations

Author notes

Article

History

Page count

Funding

Categories

Custom metadata

Comments

Comment on this article

Similar content 642

Cited by 6

Most referenced authors 85