Affinity Purified Antibodies (APA)
AfAB to human Ig and animal Ig are obtained from rabbit or goat antiserum using highly purified proteins as immunogens. AfAB are purified from antiserum using antigens immobilized on Sepharose CL-4B.
Cross-reacting antibodies are removed by solid-phase immunoabsorption. Some AfAB preparations are additionally fractionated by affinity: they contain only the fraction of high-affinity or low-affinity antibodies. The products are supplied in 0.02 M phosphate-buffered saline, pH 7.3, preservative - sodium azide.