Specific removal of antibody by extracorporeal circulation over antigen immobilized in collodion-charcoal

Studies were undertaken to determine whether BSA immobilized in collodion membranes adherent to activated charcoal particles, would be capable of specifically removing circulating BSA antibody in vitro and in vivo in an extracorporeal system in dogs. Up to 59-8 mg of BSA were retained in collodion membranes adherent to small particles. In vitro studies demonstrated that immobilized BSA could specifically reduce BSA binding activity from circulating antisera. For in vivo studies, an extracorporeal circulation system was established and arterial blood was circualted through a continuous flow celltrifuge in which plasma was separated from formed elements of the blood. Only plasma was circulated over the BSA collodion-charcoal immunoadsorbent. Anti-BSA and anti-HSA atibodies were passively infused into dogs and, after an equlibration period of 12 or 15 min, plasma was passed over the BSA collodion-charcoal immunoadsorben. Plasma exhibited a sharp reduction in BSA binding over the next 30-60 min with only slight reduction in anti-HSA binding the same period. Dogs, actively immunized to BSA and HSA, were also treated by extracorporeal plasma perfusion over BSA collodion-charcoal. A specific decline in BSA binding of sera, was again observed with minimal changes in HSA binding. A post-perfusion rebound of BSA binding was observed which reached pre-perfusion levels after 6-8 days. A second treatment during the rebound period also resulted in a specific decline in BSA binding with a similar pattern of antibody rebound. There were no significant changes in I-labelled BSA recorded on the charcoal before and after in vivo procedures and no signifcant alterations in haematocrit, serum sodium, potassium, calcium, magnesium or creatinine levels before and after the procedures. These data suggests that antigen-coated charcoal may specifically withdraw circulating antibodies in vivo with minimal release of the entrapped antigen and little alteration in the host's haematological and biochemical status.