Fina Biosolutions_Carrier Proteins_rTTHc and related

Recombinant Tetanus Toxin Heavy Chain Fragment C (rTTHc)

Tetanus toxoid (TT) is frequently used as a carrier protein for conjugate vaccines, in addition to being a component of the DPT vaccine. TT contains strong T cell epitopes. However, as a toxoided protein, many of the surface lysines are blocked by the toxoiding process. Furthermore, TT is not a uniform product, since each manufacturer has its own specific toxoiding and purification process. Tetanus toxoid also tends to aggregate with age and is not generally affordable in the quantities needed for research and early clinical work.

TT heavy chain fragment C (rTTHc) is the the C terminal fragment of the toxin1. rTTHc is devoid of the toxin’s enzymatic activity but contains the binding site necessary for uptake of the toxin by neurons2,3 and is the most immunogenic part of the toxin4. Fragment C contains the powerful T cell epitopes of tetanus toxin without the toxicity.

FinaBio offers recombinant TTHc (rTTHc), combining the advantages of the toxoid with the reproducibility of a recombinant protein. Our rTTHc is expressed as a properly-folded, soluble protein in E. coli cytoplasm.

rTTHc is currently available in research grade and is shipped on dry ice.


  1. Helting and Zwisler. Structure of Tetanus Toxin: I. Breakdown of the Toxin Molecule. J Biol. Chem. 252:137, 1977.
  2. Roux et al. C-terminal fragment of tetanus toxin: its use in neuronal network analysis and its potential as non-viral vector J Soc Biol. 199:35, 2005.
  3. Sinha et al. Analysis of mutants of tetanus toxin Hc fragment: ganglioside binding, cell binding and retrograde axonal transport properties. Mol Microbiol. 37:1041, 2000.
  4. Ramakrishnan et al., Utility of recombinant fragment C for assessment of anti-tetanus antibodies in plasma. Diagn Microbiol Infect Dis. 82:11, 2015.


Fina Biosolutions now offers rTTHc pre-labeled with maleimide, allowing for the easy conjugation of thiolated antigens. FinaBio’s rTTHc, is labeled with ~10 maleimides. The labeled protein is provided frozen, ready to thaw and conjugate to a thiol-containing antigen.

Examples of antigens that have been conjugated to rTTHc-maleimide include cysteine-peptides, thiol-labeled oligosaccharides, polysaccharides and proteins. Depending on the nature of the antigen, gel filtration or spin filters can be used to purify the conjugate.


  • ~10 Maleimide/rTTHc
  • 5 mg/ml
  • PBS + 10% sucrose, pH 6.8
  • Store at <-20°C

Note: Use within 1 hr after thawing. The buffer is a pH compromise as rTTHc will denature in acidic buffers while the maleimide linker will hydrolyze in basic buffers. Care should be taken to keep the conjugation pH between 6.8 and 7.8. We recommend familiarity with thiol-ether conjugation. See GT Hermanson, Bioconjugate Techniques.

rTTHc related product list

Product Size
rTTHc 1 mg, 5 mg, 10 mg, 25 mg, 50 mg
rTTHC-bromacetate 1 mg, 5 mg, 10 mg, 25 mg, 50 mg
rTTHC-maleimide 1 mg, 5 mg, 10 mg, 25 mg, 50 mg

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