Immunoabsorbents prepared from cell membrane antigens: efficiency of incorporation and shedding of protein during use

Abstract

Immunoabsorbents for the removal of antibodies against cell membrane antigens have been prepared by a variety of techniques in common use. Cells were surface-labelled by lactoperoxidase-catalysed radioiodination, and the different immunoabsorbent preparations were compared in terms of efficiency of incorporation and shedding of membrane material during use. Whole cells, either unfixed or fixed with glutaraldehyde, shed substantial amounts of material during absorption. Detergent extracts of surface-labelled cells were coupled covalently to agarose beads by cyanogen bromide activation, periodate oxidation, or epoxy activation of the gel. Although these immunoadsorbents were much more stable than whole cells, shedding could not be eliminated entirely. Minimal shedding was achieved using freshly washed epoxy-based immunoadsorbents. The possible consequences of shed protein in immunoabsorbed sera are emphasised.