Ricin chain A. This vaccination is effective for several months due to the body's production of antibodies to the foreign protein. In 1978 Bulgarian defector Vladimir Kostov survived a ricin attack similar to the one on Georgi Markov, probably due to his body's production of antibodies. When a ricin-laced pellet was removed from the small of his back it was found that some of the original wax coating was still attached. For this reason only small amounts of ricin had leaked out of the pellet, producing some symptoms but allowing his body to develop immunity to further poisoning. The seeds of
2003 ricin letters 2003 ricin letters The 2003 ricin letters refer to two ricin-laden letters found on two separate occasions between October and November 2003. One letter was mailed to the White House and intercepted at a processing facility; another was discovered with no address in South Carolina. A February 2004 ricin incident at the Dirksen Senate Office Building was initially connected to the 2003 letters as well. The letters were sent by an individual calling him- or herself "Fallen Angel". The sender, who claimed to own a trucking company, expressed anger over changes in federal trucking regulations. As of 2008, no connection