Abstract
Tetanus toxin has a molecular weight of 150,000 and is composed of three domains A, B and C. Two complementary non-toxic fragments, the light chain A (52,000) and the heavy chains B-C (98,000) were isolated from extracellular nicked toxin. Dissociation by mild enzyme treatment with Papain created another set of fragments, namely A-B and C. Of these fragments, fragment C is the most important in epitope studies. Fragment C is capable of eliciting antibodies which block neurotoxicity, though it is itself atoxic. It has been concluded that the binding site for gangliosides is located on the heavy chain portion of tetanus toxin, in the region comprised of Fragment C. The paper discuses how crude Tetanus Toxin and Toxoids, can be enzymatically digested using Papain to obtain a major polypeptide (C-Fragment), having a molecular weight of approximately 47,000 (±5%) and how the fragment can be isolated and purified using Sephadex G-100. The pure C Fragment was later collected after passing the same through a Tosoh TSK gel G3000SW Column. Comparative analysis with commercially available C fragment, indicated its purity by HPLC and Western Blot analysis. The purified C fragment was used to study the reactivity of Antibodies against Tetanus. Commercially available C fragment is very expensive and the method describes a simplified and cost effective method of isolating the same.
