Preparation of Tetanus Toxoid

• Bacterial Growth:
  A highly toxigenic strain of Clostridium tetani is grown in a semi-synthetic medium.

• Toxin Production:
  During bacterial growth and lysis, the tetanus toxin is released into the supernatant.

• Toxoid Formation:
  The toxin is treated with formaldehyde, which:

  • Alters specific amino acids.

  • Induces minor molecular conformational changes.

  • Converts the active toxin into an inactive toxoid (non-toxigenic).

• Purification:
  Ultrafiltration is used to remove residual and unnecessary proteins from the culture.

• Final Product:

  • The toxoid is physico-chemically similar to the native toxin.

  • It induces cross-reacting antibodies.

  • It is non-toxic, making it safe for use in vaccines.

Selection of highly toxigenic strain of Clostridium tetani
        ↓
Growth in semi-synthetic medium under controlled conditions
        ↓
Bacterial growth and lysis → release of tetanus toxin into supernatant
        ↓
Treatment with formaldehyde
  → Alters specific amino acids
  → Induces minor conformational changes
  → Converts toxin to non-toxic toxoid
        ↓
Ultrafiltration
  → Removes residual and unnecessary proteins
        ↓
Final product: Tetanus toxoid
  → Non-toxic
  → Antigenically similar to native toxin
  → Capable of inducing protective antibodies