Production of a High-Titred Sheep Antiserum Against Human Factor IX and Immunological Demonstration of Factor IX Aggregates

Abstract

Plasma factor IX was purified from a factor IX concentrate by a five step procedure including absorption onto aluminium hydroxide, affinity chromatography on heparin-coupled Sepharose 4B, preparative disc gel electrophoresis, affinity chromatography on an immunosorbent column with rabbit antiserum against factor X and chromatography on DE-52 cellulose. The pooled fractions had a specific activity of approximately 250 U/mg protein. A sheep was immunized with pooled and concentrated fractions. An antiserum was produced which gave one main precipitin band and occasionally an additional weak band against normal plasma in double immunodiffusion. At a dilution of 1/100-1/200 the antiserum neutralized 90% of the factor IX activity in an equal volume of normal plasma.Polyacrylamide disc gel electrophoresis of the fractions from DE-52 cellulose revealed one major and three minor bands with lower electrophoretic mobility and intensity. The three minor bands disappeared on disc gel electrophoresis in the presence of 10 M urea. When the disc electrophoresis gel was submitted to electrophoresis into anagarose gel containing the sheep antiserum or a previously characterized rabbit antiserum against factor IX, four precipitin arcs corresponding to the four bands were seen. A reaction of identity was seen between the four arcs. This study demonstrates that a highly potent antiserum may be produced against factor IX in sheep.