According to the World Health Organisation (WHO), cholera affects three to five million people worldwide and causes between 100,000 and 130,000 deaths per year.
We have prepared a recombinant form of Cholera toxin that can be used as a marker for neuronal cells, together with specific monoclonal antibodies for detection of the toxin.
Vibrio cholerae background
Vibrios are highly motile, curved shaped rods with a single polar flagellum that is used for self-propulsion. Vibrio cholerae is a non-spore-forming, gram-negative, facultative anaerobic bacterium of the family Vibrionaceae. V. cholerae is the causative agent of cholera, which is a diarrhoeal disease of the small intestine. Transmission of V.cholerae to humans occurs via the faecal-oral route and through the ingestion of contaminated water or food (WHO).
There are numerous serogroups of V. cholerae but until 1992 the only vibrios that caused epidemic cholera were of the serogroup O1. The O1 serogroup is classified as two biotypes, classical and El Tor, and is further classified into two major serotypes, Inaba (AC) and Ogawa (AB). In 1993, a new pathogenic serogroup emerged in Bangladesh that was designated O139 Bengal (Silva AJ).
Cholera is asymptomatic in many cases but does cause severe, watery diarrhoea and dehydration in some individuals, which if untreated can rapidly lead to death. Cholera is reported to be endemic in many countries and seven cholera pandemics have been reported globally. The current pandemic is characterized by the predominance of the O1 serogroup of the El Tor biotype, with sporadic emergence of serogroup O139 (WHO).
The two major virulence factors expressed by V. cholerae O1 and O139 are cholera toxin (CT) and the toxin-coregulated pilus (TCP). 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.
World Health Organization: Media centre; Cholera
Silva AJ, Benitez JA. (2016). Vibrio cholerae Biofilms and Cholera Pathogenesis. PLoS Negl Trop Dis.Feb 4;10(2):e0004330. PMID: 26845681
Vibrio cholerae Antigens
We offer recombinant Cholera toxin subunit B (CTXB) protein expressed in mammalian cells, which 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.
Vibrio Cholerae Antibodies
The Native Antigen Company offer a pair of monoclonal antibodies that are highly specific for the beta sub-unit of Cholera toxin, permitting the development of immunoassays and detection applications for the protein.
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