Cholera Toxin B Subunit Shows More Intense Affinity to Schwann Cells than Neurons : In Situ and In Vivo Staining

Conjugates of horseradish peroxidase (HRP) with cholera toxin (CT) are known to be more effective as a probe for studies of neuronal connectivity than HRP only, because of the affinity of CT for GM1 ganglioside which may be richly expressed on neuronal plasma membranes. The present in situ and in vivo staining using CT-fluorescein isothiocyanate (CT-FITC) and CT-HRP demonstrated their intense binding to Schwann cells rather than neurons. Exogenous GM1 successfully competed for the CT binding sites on Schwann cells. This finding suggests the rich existence of GM1 on the Schwann cell surface