Tetanus neurotoxin (TeNT)

Tetanus neurotoxin (TeNT), also known as tetanospasmin, is an extremely potent protein toxin produced by the bacterium Clostridium tetani and is the causative agent of tetanus (StatPearls, 2023). The toxin is a 150 kDa protein composed of a heavy chain (100 kDa) responsible for receptor binding and translocation, and a light chain (50 kDa) that functions as a zinc-dependent metalloprotease (UniProt P04958). TeNT enters the peripheral nervous system and undergoes retrograde axonal transport to reach the central nervous system, where it specifically cleaves synaptobrevin-2 (VAMP2) in inhibitory interneurons (PubMed, PMC7076335). This cleavage prevents the release of inhibitory neurotransmitters like GABA and glycine, leading to the characteristic muscle rigidity and spasms associated with the disease. In clinical practice, the toxin is inactivated with formaldehyde to create tetanus toxoid, which is the primary antigenic component in vaccines used to elicit protective neutralizing antibodies (CDC, 2022). Therapeutic management involves both active immunization with the toxoid and passive immunization with tetanus immune globulin to neutralize the toxin before it can bind to neuronal membranes.

Other names

TetanospasminTetanus toxinTeLTetXTetanus toxoid

Tetanus toxoid serves as an antigen to induce active immunity by stimulating the production of neutralizing IgG antibodies that bind to the toxin's C-terminal binding domain, preventing neuronal entry. Tetanus immune globulin provides passive immunity by directly neutralizing circulating toxin before it can bind to nerve endings.