title: Detection of anthrax toxin in the serum of animals infected with Bacillus anthracis by using engineered immunoassays.
abstract: Several strategies that target anthrax toxin are being developed as therapies for infection by Bacillus anthracis. Although the action of the tripartite anthrax toxin has been extensively studied in vitro, relatively little is known about the presence of toxins during an infection in vivo. We developed a series of sensitive sandwich enzyme-linked immunosorbent assays (ELISAs) for detection of both the protective antigen (PA) and lethal factor (LF) components of the anthrax exotoxin in serum. The assays utilize as capture agents an engineered high-affinity antibody to PA, a soluble form of the extracellular domain of the anthrax toxin receptor (ANTXR2/CMG2), or PA itself. Sandwich immunoassays were used to detect and quantify PA and LF in animals infected with the Ames or Vollum strains of anthrax spores. PA and LF were detected before and after signs of toxemia were observed, with increasing levels reported in the late stages of the infection. These results represent the detection of free PA and LF by ELISA in the systemic circulation of two animal models exposed to either of the two fully virulent strains of anthrax. Simple anthrax toxin detection ELISAs could prove useful in the evaluation of potential therapies and possibly as a clinical diagnostic to complement other strategies for the rapid identification of B. anthracis infection.
authors.affiliation: Institute for Cellular and Molecular Biology, University of Texas at Austin, 1 University Station, 78712, USA.
authors.forename: Robert
authors.initials: R
authors.lastname: Mabry
authors.forename: Kathleen
authors.initials: K
authors.lastname: Brasky
authors.forename: Robert
authors.initials: R
authors.lastname: Geiger
authors.forename: Ricardo
authors.initials: R
authors.lastname: Carrion
authors.forename: Gene B
authors.initials: GB
authors.lastname: Hubbard
authors.forename: Stephen
authors.initials: S
authors.lastname: Leppla
authors.forename: Jean L
authors.initials: JL
authors.lastname: Patterson
authors.forename: George
authors.initials: G
authors.lastname: Georgiou
authors.forename: B L
authors.initials: BL
authors.lastname: Iverson
mesh_terms: D000818:Animals; D000881:Anthrax / Q000097:blood* / Q000382:microbiology / Q000662:veterinary; D000907:Antibodies, Bacterial / Q000097:blood*; D001408:Bacillus anthracis; D001427:Bacterial Toxins / Q000097:blood* / Q000276:immunology; D004797:Enzyme-Linked Immunosorbent Assay / Q000379:methods; D005260:Female; D006168:Guinea Pigs; D007106:Immune Sera / Q000097:blood; D015151:Immunoblotting / Q000379:methods; D008297:Male; D011817:Rabbits; D018000:Receptors, Peptide / Q000737:chemistry / Q000276:immunology; D013171:Spores, Bacterial / Q000472:pathogenicity
chemical_list: D000907:Antibodies, Bacterial; D001427:Bacterial Toxins; D007106:Immune Sera; D018000:Receptors, Peptide; C070309:anthrax toxin receptors