Tetanus toxin heavy chain fragment (TetC) (TetC)

The Tetanus toxin heavy chain fragment, specifically the C-terminal domain known as Fragment C (TetC), is a 50 kDa non-toxic portion of the neurotoxin produced by Clostridium tetani (UniProt P04958). It serves as the primary binding domain, mediating high-affinity interactions with polysialogangliosides like GT1b and GD1b on the surface of motor neurons (StatPearls, NBK459217). This binding is essential for the toxin's internalization and subsequent retrograde axonal transport to the central nervous system, where the light chain eventually inhibits neurotransmitter release (PubMed, 11544348). In clinical practice, this fragment is a critical component of tetanus toxoid vaccines, acting as a potent immunogen that elicits neutralizing antibodies to prevent the disease (CDC, Pink Book). These antibodies function by sterically hindering the fragment's ability to bind to neuronal receptors. Furthermore, due to its specific neuronal targeting, the fragment is extensively researched as a carrier for delivering therapeutic molecules across the blood-brain barrier or directly into neurons (PubMed, 25668253).

Other names

Fragment CTTCTetCHc fragmentC-fragment of tetanus toxinTetanus toxoid fragment C

The fragment acts as an antigen to stimulate the production of neutralizing IgG antibodies that bind to the heavy chain, thereby blocking the toxin's ability to attach to neuronal ganglioside receptors and preventing its entry into the nervous system (CDC, Pink Book; StatPearls, NBK459217).