Fragment A-B of tetanus toxin does not block neuromuscular transmission in the goldfish.

ABSTRACT

While 4 micrograms of Fragment A-B of tetanus toxin (which lacks the binding site for nervous tissue) causes flaccid paralysis and death in mice, 26 micrograms has no toxic effect in goldfish. Antibodies to either A-B or to fragment C (which contains the binding site) block the paralytic effect of whole toxin in goldfish. It is concluded that binding is necessary for the neuromuscular blocking action of the toxin in goldfish.