Purification of rabbit anti-human fibrinogen antibodies cross reactivity of mammalian fibrinogen.

A simple isolation procedure of highly purified and unaltered rabbit antibodies to human fibrinogen is described. The method used is based upon the preferential adsorption of fibrinogen by barium sulfate at acid pH. After redissolution of the specific precipitate and dissociation of the antigen-antibody complexes at pH 2.4, the fibrinogen is removed by adsorption on barium sulfate, while the antibody protein stays in solution. BaSO4 is eliminated by centrifugation and the supernatant is neutralized and concentrated by ammonium sulfate fractionation (40% saturation). A concentrated solution of specific anti-fibrinogen antibodies is thus obtained; the latter can be used to prepare, by selective immunprecipitation, a fibrinogen free plasma, and to analyze precipitin patterns in cross reacting systems.