VMC 221: Veterinary Immunology and Serology (1+1)

CONCENTRATION OF IMMUNOGLOBINS BY DIALYSIS

• This is used for concentration of proteins with high molecular weights.

Procedure 

• The dialyzed ammonium precipitate in the dialysis bag can be concentrated with sucrose. 
• It is placed in a beaker on one side and covered with finely powdered sucrose or polyvinyl pyrrolidone (PVP).
• The beaker is tilted to keep the bag on higher side and to allow the fluid coming out of the bag to flow down.
• Water and other low molecular weight products ooze out of the bag and form viscous solution of sucrose or PVP.
• To maintain the initial rapid rate of flow of fluid, the dialysis bag should be squeezed by twisting from one end and tied from time to time.
• Concentrated Ig from the bag is recovered after washing it well with distilled water from out side.
• Inside of the bag may be rinsed with small volume of PBS.