Immunogenic Contaminants in Mouse Nerve‐Growth Factor

Abstract
Experiments are described that confirm the presence of .gamma.-globulin in standard preparations of mouse nerve growth factor (7-S complex and .beta. subunit) and show that antibodies to this protein are present in horse antisera to the growth factor. These antibodies may be partially removed by absorption with soluble antigen and totally removed by affinity chromatography on columns of insolubilized antigen. These procedures do not affect the potency of the antiserum in vitro or in vivo. Contaminating globulin may be removed from samples of the isolated .beta. subunit by gel filtration to give an immunochemically pure preparation which will permit more meaningful studies on nerve growth factor and its antiserum.