B. thuringiensis Cry1Ac

Cry1Ac protoxin is a crystal protein produced by the bacterium Bacillus thuringiensis during sporulation. Cry1Ac is one of the delta endotoxins produced by this bacterium which have insecticidal properties. Because of this, it has been introduced into commercially important crops (eg cotton and tomato by Monsanto) and by genetic engineering in order to confer pest resistance on those plants. Cry1Ac is used as a mucosal adjuvant (an immune-response enhancer). It has been used in the ongoing research into the use of a vaccine against the amoeba Naegleria fowleri. This amoeba can invade and attack the human nervous system and brain, causing primary amoebic meningoencephalitis which is nearly always fatal.