Inter-alpha-trypsin-inhibitor (ITI): use of immunoadsorbents for preparation of anti-ITI antiserum, ITI-free human serum and purified ITI

Immunoaffinity chromatography was used to prepare various reagents required for studies of inter-alpha-trypsin-inhibitor (ITI), a human protease inhibitor. To absorb an initially polyspecific anti-ITI antiserum, a mixture of all serum proteins except ITI was prepared as follows: normal human serum was gel filtered (Sephacryl S-300) and the part of peak II containing normal ITI was removed; another aliquot of serum was heated, gel filtered, and peak I which contained all ITI molecules in aggregated form was discarded. The remaining fractions from both gel filtrations were immobilized on gel and used as an immunoadsorbent. The monospecific anti-ITI antiserum thus obtained was immobilized on gel and could bind ITI from human serum. Under conditions chosen to weaken non-specific adsorptions and desorb ITI without denaturation, this immunoadsorbent made it possible to prepare ITI-free serum and purified ITI with biological activity.