If nervous impulses cannot be checked by normal inhibitory mechanisms, it produces the generalized muscular spasms characteristic of tetanus. Tetanospasmin appears to act by selective cleavage of a protein component of synaptic vesicles, synaptobrevin II , and this prevents the release of neurotransmitters by the cells. Binding appears to depend on the number and position of sialic acid residues on the ganglioside. Isolated B fragments, but not A fragments will bind to the ganglioside. Binding appears to be an irreversible event.
Recovery depends on sprouting a new axon terminal.
Immunity Unlike other diseases, such as diphtheria, recovery from the natural disease usually does not confer immunity, since even a lethal dose of tetanospasmin is insufficient to provoke an immune response. Three injections are given in the first year of life, and a booster is given about a year later, and again on the entrance into elementary school. Whenever a previously-immunized individual sustains a potentially dangerous wound, a booster of toxoid should be injected. Wherever employed, intensive programs of immunization with toxoid have led to a striking reduction in the incidence of the disease. Clostridium botulinum C. botulinum is a large anaerobic bacillus that forms subterminal endospores.