Staphylococcal Enterotoxin B (SEB)
Staphylococcal Enterotoxin B (SEB) is one of seven toxins produced by the bacteria Straphylococcal aureus. As an exotoxin, SEB is secreted by the bacteria. An enterotoxin, SEB affects the ion and water transport system of the intestines and is typically associated with food poisoning. It also induces nonmenstrual toxic shock syndrome (TSS). SEB is a stable compound that is soluable in water and can be stored in freeze-dried condition for a year. The toxin is insensitive to temperature fluxuations and can resist boiling for several minutes. SEB is constructed of 239 amino acids residues.
As a possible biological weapons agent, SEB is stable, easily transformed into an aerosol, can produce multiorgan and system wide symptoms, and in extremely high doses, SEB induces shock and death. Symptoms of an aerosolized attack differ from ingestion; these symptoms consist of high fever, chills, headache, muscle ache, dry cough and inflammation of the eye lids. Aerosolized SEB may also cause trouble with breathing, chest pains, and the development of fluid in the lungs. Typically, SEB is considered an incapacitating agent that causes debilitation up to two weeks. Small amounts can debilitate large numbers of victims since only 1/4,000 of a microgram induces illness in 50% of the human population and 1/200 of a microgram to induce fatality in 50% of the population. The agent cannot be transmitted from person to person.
Ingested SEB generates symptoms through the release of histamine and leukotrienes. Aerosolized SEB fastens to the major histocompatability complex (MHC) class II proteins which stimulate the activation of T cells and cytokines. Often, Straphylococcal aureus is known as a superantigen because its toxin creates a powerful response from the immune system.
History of SEB as a Biological Weapons Agent
In the 1960s, the United States Bioweapons Programs studied and stockpiled Staphylococcal Enterotoxin B, code named PG, as an incapacitating biological agent.
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