Preparation of antibody fragments: conditions for proteolysis compared by SDS slab-gel electrophoresis and quantitation of antibody yield.

Monovalent antibody fragments are now recognized to have major advantages over intact immunoglobulin G in immunohistochemistry, but the methods commonly used for their preparation do not necessarily give a maximal yield of active antibody fragments and take little account of species differences. Sodium dodecyl sulphate (SDS) slab-gel electrophoresis demonstrated large differences in the susceptibility to digestion of antibodies of different species and was found to be valuable in the selection of optimal digestion conditions. Promising results were obtained with sheep antibodies by use of low concentrations of trypsin, and an immunoadsorbent technique showed a high yield of antibody fragments.