Specific, Sensitive, and Quantitative Enzyme-Linked Immunosorbent Assay for Human Immunoglobulin G Antibodies to Anthrax Toxin Protective Antigen

Emerg Infect Dis. 2002 Oct;8(10):1103-10. doi: 10.3201/eid0810.020380.

Abstract

The bioterrorism-associated human anthrax epidemic in the fall of 2001 highlighted the need for a sensitive, reproducible, and specific laboratory test for the confirmatory diagnosis of human anthrax. The Centers for Disease Control and Prevention developed, optimized, and rapidly qualified an enzyme-linked immunosorbent assay (ELISA) for immunoglobulin G (IgG) antibodies to Bacillus anthracis protective antigen (PA) in human serum. The qualified ELISA had a minimum detection limit of 0.06 micro g/mL, a reliable lower limit of detection of 0.09 micro g/mL, and a lower limit of quantification in undiluted serum specimens of 3.0 micro g/mL anti-PA IgG. The diagnostic sensitivity of the assay was 97.8%, and the diagnostic specificity was 97.6%. A competitive inhibition anti-PA IgG ELISA was also developed to enhance diagnostic specificity to 100%. The anti-PA ELISAs proved valuable for the confirmation of cases of cutaneous and inhalational anthrax and evaluation of patients in whom the diagnosis of anthrax was being considered.

MeSH terms

  • Anthrax / diagnosis
  • Anthrax / immunology*
  • Antibodies, Bacterial / immunology*
  • Antigens, Bacterial / immunology*
  • Bacillus anthracis / immunology*
  • Bacterial Toxins / immunology*
  • Bioterrorism
  • Disease Outbreaks
  • Enzyme-Linked Immunosorbent Assay / methods*
  • Humans
  • Immunoglobulin G / immunology*
  • Sensitivity and Specificity

Substances

  • Antibodies, Bacterial
  • Antigens, Bacterial
  • Bacterial Toxins
  • Immunoglobulin G
  • anthrax toxin