Cholera Toxin B subunit

Cholera Toxin B (CTB) is secreted by Vibrio cholerae. CTB functions as an oral subunit vaccine for cholera, which is associated with acute watery diarrhoea. It acts as a mucosal immunogen. Cholera toxin (CT) stimulates cell surface molecules, such as antigen presenting cells (APCs), murine and human dendritic cells (DCs). CT also has immunomodulatory properties. It induces the secretion of interleukin 1 (IL-1) from macrophages and enhances their APC function.

Cholera Toxin B subunit has been used:

• in immunofluorescence
• in the analysis of major histocompatibility complex (MHC) class II lipid raft partitioning
• in live cell three-dimensional tracking of SH-SY5Y human neuroblastoma cells
• to assess the toll-like receptors (TLR) and FcRγ (Fc receptor γ chain) – CARD9 (caspase recruitment domain family member 9) activation by cholera Toxin B (CTB)

The cholera toxin B subunit is used for track tracing in neurological research, taking advantage of GM1 ganglioside binding and retrograde transport. Tissue culture cells treated with cholera toxin are not killed and tissues of animals do not become necrotic.

Biotin content ~1.0 mole/mole protein.

Lyophilized powder containing sodium phosphate buffer salts, sodium azide and sodium EDTA.

Activity measured by ELISA using ganglioside GM₁-coated multiwell plates, rabbit anti-Cholera toxin B subunit, and peroxidase-labeled goat anti-rabbit IgG as the secondary antibody. 50% saturation of binding is achieved with 0.02-1 μg of Cholera toxin B subunit-biotin conjugate per mL. The conjugated B subunit gives a similar value for 50% binding to that of unconjugated B subunit from which it is prepared.