Antibiotics are effective against anthrax only if given at a very early stage of infection when symptoms are non-specific and diagnosis is difficult. As a consequence, early diagnosis is central to medical countermeasures designed to treat treatment nascent infection. Bacillus anthracis is surrounded by a capsule composed of poly-?-D-glutamic acid (PGA). Preliminary studies found that PGA is shed into serum and urine during animal models of pulmonary anthrax and that immunoassay for PGA is an effective surrogate for the blood culture in diagnosis. PGA appears in blood at or before the time that a blood sample will yield a positive blood culture. However, unlike the blood culture which can take several days to produce positive results, immunoassay in rapid format can produce positive results in seconds to minutes. Additional studies found that the EIA can be successfully migrated to a lateral flow immunochromatographic (LFI) format. The LFI assay platform is rapid, highly sensitive, easy to use, highly adaptable, and cost effective. The overall hypothesis is that immunoassay for PGA in blood and urine is an effective surrogate for the blood culture in diagnosis of anthrax. The overall goal is to move the project from proof-of-concept to optimization of an immunoassay in LFI format and validation of the assay using human samples and models of inhalation anthrax in rabbits and Cynomolgus macaques.
The Specific Aims are to i) produce and optimize an immunoassay in LFI format, ii) evaluate and validate immunoassay performance in a laboratory setting and iii) validate immunoassay performance using animal models and samples from human anthrax. This is a mature project that has moved from i) an initial concept for a potential diagnostic target to ii) development a of research-grade immunoassay to iii) proof-of-concept target validation in animal models to iv) production of a prototype immunoassay in point-of-care format. If successful, the proposed diagnostic tool will significantly enhance readiness for a bioterrorism incident.
Immunoassay for detection of capsular antigen in blood or urine has great promise for rapid diagnosis of inhalational anthrax. The project goal is to produce a diagnostic test that will dramatically reduce the time to diagnosis of inhalational anthrax with a consequent increase in patient response to treatment.
|Kozel, Thomas R; Burnham-Marusich, Amanda R (2017) Point-of-Care Testing for Infectious Diseases: Past, Present, and Future. J Clin Microbiol 55:2313-2320|
|Ezeanolue, Echezona E; Nwizu, Chidi; Greene, Gregory S et al. (2016) Brief Report: Geographical Variation in Prevalence of Cryptococcal Antigenemia Among HIV-Infected, Treatment-Naive Patients in Nigeria: A Multicenter Cross-Sectional Study. J Acquir Immune Defic Syndr 73:117-21|
|Gates-Hollingsworth, Marcellene A; Perry, Mark R; Chen, Hongjing et al. (2015) Immunoassay for Capsular Antigen of Bacillus anthracis Enables Rapid Diagnosis in a Rabbit Model of Inhalational Anthrax. PLoS One 10:e0126304|
|Kozel, Thomas R (2014) The road to toxin-targeted therapeutic antibodies. MBio 5:e01477-14|
|Hansen, Jessica; Slechta, E Susan; Gates-Hollingsworth, Marcellene A et al. (2013) Large-scale evaluation of the immuno-mycologics lateral flow and enzyme-linked immunoassays for detection of cryptococcal antigen in serum and cerebrospinal fluid. Clin Vaccine Immunol 20:52-5|
|Hubbard, Mark A; Thorkildson, Peter; Kozel, Thomas R et al. (2013) Constant domains influence binding of mouse-human chimeric antibodies to the capsular polypeptide of Bacillus anthracis. Virulence 4:483-8|
|Hubbard, Mark A; Thorkildson, Peter; Welch, William H et al. (2013) Stereo-selective binding of monoclonal antibodies to the poly-?-D-glutamic acid capsular antigen of Bacillus anthracis. Mol Immunol 55:337-44|
|Hovenden, Maria; Hubbard, Mark A; Aucoin, David P et al. (2013) IgG subclass and heavy chain domains contribute to binding and protection by mAbs to the poly ?-D-glutamic acid capsular antigen of Bacillus anthracis. PLoS Pathog 9:e1003306|
|Gates-Hollingsworth, Marcellene A; Kozel, Thomas R (2013) Serotype sensitivity of a lateral flow immunoassay for cryptococcal antigen. Clin Vaccine Immunol 20:634-5|