Targeting Tools: CTB-SAP

CTB-SAP (Cat. #IT-14) is a conjugate between the cell-binding component of cholera toxin (the B chain) and saporin. CTB binds to GM1 (monosialotetrahexosylganglioside), which is present on the surface of different neurons. It has been suggested to be involved in many problems (besides the most famous in the gut: cholera) of neuronal systems: Parkinson’s, motor neuron degeneration, spinal cord injury, and Alzheimer’s disease among others.

As seen in the figure, the cytotoxicity is dependent on the quantity of GM1 on the cell surface, from little effect at zero expression to pM ED50 at high expression. The use of this conjugate has recently been the subject of several studies, and is providing use to researchers in many fields.

The percent shift as determined by flow cytometry staining with CTB-FITC was plotted against the log concentration of the ED50 in moles/L of CTB-SAP for six cell lines. RIN 3B and RIN-m5F are rat insulinoma cell lines; T84 is a human colon carcinoma cell line; NG108-15 is a rat-mouse hybrid neuroblastoma/glioma cell line; RBL-2H3 is a rat basophilic leukemic cell line; HS294T is a human melanoma cell line. The plotted data show a distinct correlation between the number of CTB binding sites and the ED50 of CTB-SAP.
Data were analyzed by Prism (GraphPad).