A simplified procedure for the isolation of immunoglobulins from human serum using a novel type of thiophilic gel at low salt concentration.

By coupling 3-(2-mercaptoethyl)quinazoline-2,4(1H,3H)dione (MECH) to divinyl sulfone activated agarose, a novel thiophilic matrix was obtained which allows the binding of immunoglobulins from different sources. In contrast to other thiophilic gels, antibodies are bound at low ionic strength and can easily be desorbed in intact form by elution with dilute alkali. The potential of using the MECH-gel was demonstrated by the purification of antibodies from human and animal (goat, rabbit, mouse) sera. The functional integrity of the purified antibodies was established with cytoplasmic islet cell antibodies from the sera of patients with type I diabetes and autoantibodies against thyroid peroxidase from patients with Graves' and Hashimoto's disease.