Papain-derived fragment IIc of tetanus toxin: its binding to isolated synaptic membranes and retrograde axonal transport.

The papain-derived fragment IIc of tetanus toxin, which is immunologically identical to the B-IIb fragment, has previously been shown to bind gangliosides. As could be expected from its analogy with the B-IIb fragment, the IIc fragment was also found to bind to isolated synaptic membranes and to be transported retrogradely from the axonal endings within muscle to the motoneuronal perikarya. It is concluded that the IIc fragment--like the B-IIb fragment--might also serve as a specific carrier for chemical and chemotherapeutical agents into the central nervous system.