In October of 2001, a letter containing spores of Bacillus anthracis, the bacterium that causes the deadly disease anthrax, was opened in Daschle's office at the Hart Senate Office Building in Washington, DC. Those in or near Daschle's office, judged likely to have been exposed to the spores, received antibiotics or a vaccine, as did others within or outside the building, and no deaths resulted from this act of bioterrorism. According to the new study of the event, however, people in areas assumed to be at minimal risk of exposure showed immune responses suggesting they had been exposed.
The researchers, Denise L. Doolan, PhD, MPH, Daniel A. Freilich, MD, and coworkers of the Naval Medical Research Center, Silver Spring, MD, and elsewhere, prospectively studied clinical outcomes and immune responses in 123 subjects including 83 people who were nearby when the letter containing the anthrax spores was opened; 20 who were outside the building and presumed to be unexposed; and, for comparison, six individuals vaccinated against B. anthracis, two confirmed to have had anthrax, and 12 with no known B. anthracis exposure.
The results: Immune responses occurred not only in subjects in or near the Daschle office but also in those elsewhere in the Hart building, or even outside the building; the extent of exposure was thus greater than predicted. No associations were seen between exposure levels and immune responses or symptoms, but the most-exposed subjects were the only ones to have high-magnitude responses. Low-level exposure did not appear to trigge r an antibody response, but did induce a response by cells of the immune system, Intermediate exposure induced both. Finally, cellular immune responses declined with post-exposure use of antibiotics, suggesting that the intervention impeded spore germination and implying that it may reduce the incidence of both subclinical and clinical B. anthracis infection.
In an accompanying editorial, James L. Hadler, MD, MPH, of the Infectious Diseases Section of the Connecticut Department of Public Health, commented that the study by Doolan and coworkers is "one of the few studies of the immune response to high-level, naturally occurring anthrax exposure in humans, and may be the first to describe cell-mediated responses to this pathogen." Dr. Hadler said that the study's data suggest that cell-mediated responses in B. anthracis infection may be more sensitive than antibody responses, and he recommended that future studies of anthrax vaccines investigate cellular immunity's role in inhibiting the pathogen.
Source:Infectious Diseases Society of America
Related biology news :
1. Study Models Impact Of Anthrax Vaccine
2. Anthrax test, developed by army and CDC, receives FDA approval
3. Anthrax inhibitors identified by Burnham team
4. Anthrax stops body from fighting back, study shows
5. Anthrax spores may survive water treatment
6. Anthrax inhibitor counteracts toxin, may lead to new therapeutics
7. Anthrax paralyzes immune cells with lethal toxin, UF research shows
8. Poplar trees redirect resources in response to simulated attack
9. Genetically modified natural killer immune cells attack, kill leukemia cells
10. Genetic defects give the immune system the green light to attack the pancreas
11. Columbia study shows widely used artery clearing device does not help patients during heart attack