Tetanus toxin antigen

Tetanus toxin (TeNT) is a potent neurotoxin and protein antigen produced by the bacterium *Clostridium tetani*. It is responsible for the clinical disease tetanus, characterized by spastic paralysis. The toxin is a heterodimeric protein composed of a light chain (L, ~52.4 kDa) and a heavy chain (H, ~98.3 kDa), linked by a disulfide bond. The light chain is a zinc-dependent endopeptidase that cleaves synaptobrevin/VAMP-2 or cellubrevin, disrupting neurotransmitter release. The heavy chain mediates membrane translocation and neuronal binding. TeNT binds specifically to peripheral motor neuron terminals and undergoes retrograde axonal transport to spinal cord inhibitory interneurons, ultimately blocking inhibitory neurotransmission.

Cleavage of VAMP/synaptobrevin, blocking inhibitory neurotransmission and causing spastic paralysis.