Staphylococcal Enterotoxin B

Staphylococcal enterotoxin B (SEB) is an enterotoxin produced by the bacterium Staphylococcus aureus. It is a common cause of food poisoning, with severe diarrhea, nausea and intestinal cramping often starting within a few hours of ingestion. Being quite stable,. the toxin may remain active even after the contaminating bacteria are killed. It can withstand boiling at 100°C for a few minutes. Gastroenteritis occurs because SEB is a superantigen, causing the immune system to release a large amount of cytokines that lead to significant inflammation.

Biological Warfare
The US Army Chemical Warfare Service may have supplied a vial of SEB to OSS agents during the Second World War to incapacitate a Nazi agent in North Africa at the time of the D-day invasion to prevent effective handling of intelligence in the early hours of the invasion.

The United States weaponized SEB originally as agent PG, later UC, during the Cold War. It was anticipated to have a rate-of-action of several hours and a duration-of-action of 1 – 2 days. There was a crash program to deliver a usable weapon, and there was a plan to use it in the opening hours of an invasion of Cuba during the Cuban Missile Crisis, but the plan was later rejected.

Field trials with the A/B 45-4 dry agent spray tank demonstrated that a 95 kg payload of UC was capable of neutralizing a 1000 sqmi target.

The ICt50 of UC is 2 mg·min/m³, with a probit slope of 1. The is 5 mg·min/m³, and unlike the per oral route is known to have a neurotoxic effect when inhaled.