Tetanus neurotoxin (TeNT) (TeNT)

Tetanus neurotoxin (TeNT), or tetanospasmin, is a highly potent AB-type protein toxin secreted by the anaerobic bacterium Clostridium tetani (UniProt: P04958). It is the primary etiologic agent of tetanus, a severe neurological condition marked by generalized muscle rigidity and painful spasms due to the loss of inhibitory control in the central nervous system (StatPearls: Tetanus, 2023). The toxin is composed of a 100 kDa heavy chain (H-chain) responsible for neuronal binding and a 50 kDa light chain (L-chain) that acts as a zinc-dependent metalloprotease. Following internalization and retrograde axonal transport to the spinal cord, the L-chain specifically cleaves synaptobrevin-2 (VAMP2), thereby blocking the release of inhibitory neurotransmitters such as glycine and GABA (NCBI: PMC3133546). Antigenic epitopes, particularly those located on the C-terminal domain of the heavy chain, are the critical targets for neutralizing antibodies. Vaccines utilize an inactivated form of the toxin, known as tetanus toxoid, to stimulate the immune system to recognize these epitopes and provide long-term protection, while tetanus immune globulin is used for immediate passive neutralization of the toxin (CDC: Tetanus Vaccination, 2022).

Other names

TetanospasminClostridium tetani neurotoxinTeNTTeLTetanus toxoidTetanus toxin antigenic epitopes

Tetanus toxoid vaccines induce active immunity by stimulating B-cells to produce neutralizing IgG antibodies that recognize and bind to specific antigenic epitopes on the tetanus toxin (CDC: Tetanus Vaccination, 2022). These antibodies prevent the toxin from binding to its receptors on neuronal membranes, thereby neutralizing its toxic effects. Tetanus immune globulin (TIG) provides passive immunity by delivering pre-formed antibodies that bind to circulating toxin epitopes, preventing further neuronal uptake (StatPearls: Tetanus, 2023).