Cholera Toxin Subunit B
Cholera is an acute, diarrhoeal illness caused by infection of the intestine with the bacterium Vibrio cholerae. An estimated 3-5 million cases and over 100,000 deaths occur each year around the world. The infection is often mild or without symptoms, but can sometimes be severe. Approximately one in 10 (5-10%) infected persons will have severe disease characterized by profuse watery diarrhea, vomiting, and leg cramps. In these people, rapid loss of body fluids leads to dehydration and shock. Without treatment, death can occur within hours
Cholera toxin is an oligomeric complex made up of six protein subunits: a single copy of the A subunit and five copies of the B subunit. Subunit B binds to the cell surface via GM1 gangliosides on the surface of target cells. Once bound, the entire toxin complex is endocytosed by the cell and the cholera toxin A1 (CTA1) chain is released by the reduction of a disulfide bridge. Once inside the cell subunit A activates G protein which then activates adenylate cyclase, eventually leading to enhanced efflux of chloride ions from the intestinal cells, and rapid water loss via the intestine.
Cholera toxin subunit B (CTXB) has been used as a marker for neuronal cells due to its high affinity for the GM1 ganglioside cell surface receptor on these cells. CTXB has no toxic activity by itself, and can therefore be used in cell culture. This Cholera toxin subunit B comprises Thr 22 – Asn 124 (Accession # P01556) from serotype O1 of Vibrio cholerae, and is fused with a polyhistidine tag at the C-terminus. The total calculated MW is 13.5kDa. The protein is expressed in HEK293 cells, and reduced protein migrates as a band of 18-22kDa.
****SHIPPING AND STORAGE NOTIFICATION: This recombinant protein has been lyophilised to maximise stability. It is shipped at ambient temperature, and may be stored for up to 1 year at 4C prior to reconstitution. Following reconstitution it should be stored at -80C. Extensive stability tests have shown no negative effects on antigen performance for 7 days of shipping at ambient temperature.