Immunosorbent Chemistry: A Study of Agarose‐Based Column Sorbents for the Removal of Low‐Density Lipoprotein (LDL) from Blood

Abstract: Anti‐LDL antibody was covalently attached to agarose beads in order to prepare an immunosorbent for the removal of LDL from plasma or blood. Both the conditions of antibody coupling and the type of agarose matrix used were critical to the optimization of LDL binding capacity. Sorbents binding 6–8 mg lipoprotein cholesterol/ml column volume were obtained using cyanogen bromide or glutaraldehyde coupling procedures and crosslinked 2% agarose beads. The sorbent could be regenerated by washing with 1 M acetic acid, a reagent that was also an effective disinfectant. In vitro perfusions of whole blood over small columns of 212–300 μ beads showed excellent flow rates (2 ml/min/cm² under 50–100 cm saline pressure); recovery of leukocytes and platelets exceeded 90%, and complement was not activated. Leakage of antibody and bead matrix was negligible. The antibody‐agarose beads could not be sterilized by conventional techniques, but withstood treatment with 0.34% phosphoric acid in 80% ethanol at 37°C, a novel method of chemical sterilization.